Convert FixedGridLayoutManager to kotlin
This commit is contained in:
Lucas Lima
parent
4b63e79631
commit
bf5422bc79
2 changed files with 627 additions and 927 deletions
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@ -1,927 +0,0 @@
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package dev.lucasnlm.antimine.common.level.widget;
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import android.content.Context;
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import android.graphics.PointF;
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import android.util.AttributeSet;
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import android.util.Log;
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import android.util.SparseArray;
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import android.util.SparseIntArray;
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import android.view.View;
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import android.view.ViewGroup;
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import androidx.recyclerview.widget.LinearSmoothScroller;
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import androidx.recyclerview.widget.RecyclerView;
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import java.util.HashSet;
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import java.util.List;
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public class FixedGridLayoutManager extends RecyclerView.LayoutManager {
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private static final String TAG = FixedGridLayoutManager.class.getSimpleName();
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public FixedGridLayoutManager(int columnCount, int horizontalPadding, int verticalPadding) {
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this.mTotalColumnCount = columnCount;
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this.horizontalPadding = horizontalPadding;
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this.verticalPadding = verticalPadding;
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}
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private final int verticalPadding;
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private final int horizontalPadding;
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private static final int DEFAULT_COUNT = 1;
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/* View Removal Constants */
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private static final int REMOVE_VISIBLE = 0;
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private static final int REMOVE_INVISIBLE = 1;
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/* Fill Direction Constants */
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private static final int DIRECTION_NONE = -1;
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private static final int DIRECTION_START = 0;
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private static final int DIRECTION_END = 1;
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private static final int DIRECTION_UP = 2;
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private static final int DIRECTION_DOWN = 3;
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/* First (top-left) position visible at any point */
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private int mFirstVisiblePosition;
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/* Consistent size applied to all child views */
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private int mDecoratedChildWidth;
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private int mDecoratedChildHeight;
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/* Number of columns that exist in the grid */
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private int mTotalColumnCount = DEFAULT_COUNT;
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/* Metrics for the visible window of our data */
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private int mVisibleColumnCount;
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private int mVisibleRowCount;
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/* Used for tracking off-screen change events */
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private int mFirstChangedPosition;
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private int mChangedPositionCount;
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/**
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* Set the number of columns the layout manager will use. This will
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* trigger a layout update.
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* @param count Number of columns.
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*/
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public void setTotalColumnCount(int count) {
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mTotalColumnCount = count;
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requestLayout();
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}
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/*
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* You must return true from this method if you want your
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* LayoutManager to support anything beyond "simple" item
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* animations. Enabling this causes onLayoutChildren() to
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* be called twice on each animated change; once for a
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* pre-layout, and again for the real layout.
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*/
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@Override
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public boolean supportsPredictiveItemAnimations() {
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return true;
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}
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/*
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* Called by RecyclerView when a view removal is triggered. This is called
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* before onLayoutChildren() in pre-layout if the views removed are not visible. We
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* use it in this case to inform pre-layout that a removal took place.
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*
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* This method is still called if the views removed were visible, but it will
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* happen AFTER pre-layout.
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*/
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@Override
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public void onItemsRemoved(RecyclerView recyclerView, int positionStart, int itemCount) {
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mFirstChangedPosition = positionStart;
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mChangedPositionCount = itemCount;
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}
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/*
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* This method is your initial call from the framework. You will receive it when you
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* need to start laying out the initial set of views. This method will not be called
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* repeatedly, so don't rely on it to continually process changes during user
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* interaction.
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*
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* This method will be called when the data set in the adapter changes, so it can be
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* used to update a layout based on a new item count.
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*
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* If predictive animations are enabled, you will see this called twice. First, with
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* state.isPreLayout() returning true to lay out children in their initial conditions.
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* Then again to lay out children in their final locations.
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*/
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@Override
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public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
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//We have nothing to show for an empty data set but clear any existing views
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if (getItemCount() == 0) {
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detachAndScrapAttachedViews(recycler);
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return;
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}
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if (getChildCount() == 0 && state.isPreLayout()) {
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//Nothing to do during prelayout when empty
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return;
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}
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//Clear change tracking state when a real layout occurs
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if (!state.isPreLayout()) {
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mFirstChangedPosition = mChangedPositionCount = 0;
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}
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if (getChildCount() == 0) { //First or empty layout
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//Scrap measure one child
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View scrap = recycler.getViewForPosition(0);
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addView(scrap);
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measureChildWithMargins(scrap, 0, 0);
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/*
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* We make some assumptions in this code based on every child
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* view being the same size (i.e. a uniform grid). This allows
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* us to compute the following values up front because they
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* won't change.
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*/
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mDecoratedChildWidth = getDecoratedMeasuredWidth(scrap);
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mDecoratedChildHeight = getDecoratedMeasuredHeight(scrap);
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detachAndScrapView(scrap, recycler);
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}
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//Always update the visible row/column counts
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updateWindowSizing();
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SparseIntArray removedCache = null;
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/*
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* During pre-layout, we need to take note of any views that are
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* being removed in order to handle predictive animations
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*/
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if (state.isPreLayout()) {
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removedCache = new SparseIntArray(getChildCount());
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for (int i=0; i < getChildCount(); i++) {
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final View view = getChildAt(i);
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LayoutParams lp = (LayoutParams) view.getLayoutParams();
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if (lp.isItemRemoved()) {
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//Track these view removals as visible
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removedCache.put(lp.getViewLayoutPosition(), REMOVE_VISIBLE);
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}
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}
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//Track view removals that happened out of bounds (i.e. off-screen)
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if (removedCache.size() == 0 && mChangedPositionCount > 0) {
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for (int i = mFirstChangedPosition; i < (mFirstChangedPosition + mChangedPositionCount); i++) {
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removedCache.put(i, REMOVE_INVISIBLE);
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}
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}
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}
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int childLeft;
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int childTop;
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if (getChildCount() == 0) { //First or empty layout
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//Reset the visible and scroll positions
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mFirstVisiblePosition = 0;
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childLeft = horizontalPadding;
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childTop = verticalPadding;
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} else if (!state.isPreLayout()
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&& getVisibleChildCount() >= state.getItemCount()) {
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//Data set is too small to scroll fully, just reset position
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mFirstVisiblePosition = 0;
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childLeft = horizontalPadding;
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childTop = verticalPadding;
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} else { //Adapter data set changes
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/*
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* Keep the existing initial position, and save off
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* the current scrolled offset.
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*/
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final View topChild = getChildAt(0);
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childLeft = getDecoratedLeft(topChild);
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childTop = getDecoratedTop(topChild);
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/*
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* When data set is too small to scroll vertically, adjust vertical offset
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* and shift position to the first row, preserving current column
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*/
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if (!state.isPreLayout() && getVerticalSpace() > (getTotalRowCount() * mDecoratedChildHeight)) {
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mFirstVisiblePosition = mFirstVisiblePosition % getTotalColumnCount();
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childTop = verticalPadding;
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//If the shift overscrolls the column max, back it off
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if ((mFirstVisiblePosition + mVisibleColumnCount) > state.getItemCount()) {
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mFirstVisiblePosition = Math.max(state.getItemCount() - mVisibleColumnCount, 0);
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childLeft = horizontalPadding;
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}
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}
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/*
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* Adjust the visible position if out of bounds in the
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* new layout. This occurs when the new item count in an adapter
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* is much smaller than it was before, and you are scrolled to
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* a location where no items would exist.
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*/
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int maxFirstRow = getTotalRowCount() - (mVisibleRowCount-1);
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int maxFirstCol = getTotalColumnCount() - (mVisibleColumnCount-1);
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boolean isOutOfRowBounds = getFirstVisibleRow() > maxFirstRow;
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boolean isOutOfColBounds = getFirstVisibleColumn() > maxFirstCol;
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if (isOutOfRowBounds || isOutOfColBounds) {
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int firstRow;
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if (isOutOfRowBounds) {
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firstRow = maxFirstRow;
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} else {
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firstRow = getFirstVisibleRow();
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}
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int firstCol;
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if (isOutOfColBounds) {
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firstCol = maxFirstCol;
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} else {
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firstCol = getFirstVisibleColumn();
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}
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mFirstVisiblePosition = firstRow * getTotalColumnCount() + firstCol;
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childLeft = getHorizontalSpace() - (mDecoratedChildWidth * mVisibleColumnCount);
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childTop = getVerticalSpace() - (mDecoratedChildHeight * mVisibleRowCount);
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//Correct cases where shifting to the bottom-right overscrolls the top-left
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// This happens on data sets too small to scroll in a direction.
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if (getFirstVisibleRow() == 0) {
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childTop = Math.min(childTop, verticalPadding);
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}
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if (getFirstVisibleColumn() == 0) {
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childLeft = Math.min(childLeft, horizontalPadding);
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}
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}
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}
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//Clear all attached views into the recycle bin
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detachAndScrapAttachedViews(recycler);
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//Fill the grid for the initial layout of views
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fillGrid(DIRECTION_NONE, childLeft, childTop, recycler, state, removedCache);
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//Evaluate any disappearing views that may exist
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if (!state.isPreLayout() && !recycler.getScrapList().isEmpty()) {
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final List<RecyclerView.ViewHolder> scrapList = recycler.getScrapList();
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final HashSet<View> disappearingViews = new HashSet<View>(scrapList.size());
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for (RecyclerView.ViewHolder holder : scrapList) {
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final View child = holder.itemView;
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final LayoutParams lp = (LayoutParams) child.getLayoutParams();
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if (!lp.isItemRemoved()) {
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disappearingViews.add(child);
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}
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}
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for (View child : disappearingViews) {
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layoutDisappearingView(child);
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}
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}
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}
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@Override
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public void onAdapterChanged(RecyclerView.Adapter oldAdapter, RecyclerView.Adapter newAdapter) {
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//Completely scrap the existing layout
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removeAllViews();
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}
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/*
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* Rather than continuously checking how many views we can fit
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* based on scroll offsets, we simplify the math by computing the
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* visible grid as what will initially fit on screen, plus one.
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*/
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private void updateWindowSizing() {
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mVisibleColumnCount = (getHorizontalSpace() / mDecoratedChildWidth) + 1;
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if (getHorizontalSpace() % mDecoratedChildWidth > 0) {
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mVisibleColumnCount++;
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}
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//Allow minimum value for small data sets
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if (mVisibleColumnCount > getTotalColumnCount()) {
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mVisibleColumnCount = getTotalColumnCount();
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}
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mVisibleRowCount = (getVerticalSpace()/ mDecoratedChildHeight) + 1;
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if (getVerticalSpace() % mDecoratedChildHeight > 0) {
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mVisibleRowCount++;
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}
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if (mVisibleRowCount > getTotalRowCount()) {
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mVisibleRowCount = getTotalRowCount();
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}
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}
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private void fillGrid(int direction, RecyclerView.Recycler recycler, RecyclerView.State state) {
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fillGrid(direction, 0, 0, recycler, state, null);
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}
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private void fillGrid(int direction, int emptyLeft, int emptyTop,
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RecyclerView.Recycler recycler,
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RecyclerView.State state,
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SparseIntArray removedPositions) {
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if (mFirstVisiblePosition < 0) mFirstVisiblePosition = 0;
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if (mFirstVisiblePosition >= getItemCount()) mFirstVisiblePosition = (getItemCount() - 1);
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/*
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* First, we will detach all existing views from the layout.
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* detachView() is a lightweight operation that we can use to
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* quickly reorder views without a full add/remove.
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*/
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SparseArray<View> viewCache = new SparseArray<View>(getChildCount());
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int startLeftOffset = emptyLeft;
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int startTopOffset = emptyTop;
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if (getChildCount() != 0) {
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final View topView = getChildAt(0);
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startLeftOffset = getDecoratedLeft(topView);
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startTopOffset = getDecoratedTop(topView);
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switch (direction) {
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case DIRECTION_START:
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startLeftOffset -= mDecoratedChildWidth;
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break;
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case DIRECTION_END:
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startLeftOffset += mDecoratedChildWidth;
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break;
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case DIRECTION_UP:
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startTopOffset -= mDecoratedChildHeight;
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break;
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case DIRECTION_DOWN:
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startTopOffset += mDecoratedChildHeight;
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break;
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}
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//Cache all views by their existing position, before updating counts
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for (int i=0; i < getChildCount(); i++) {
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int position = positionOfIndex(i);
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final View child = getChildAt(i);
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viewCache.put(position, child);
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}
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//Temporarily detach all views.
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// Views we still need will be added back at the proper index.
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for (int i=0; i < viewCache.size(); i++) {
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detachView(viewCache.valueAt(i));
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}
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}
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/*
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* Next, we advance the visible position based on the fill direction.
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* DIRECTION_NONE doesn't advance the position in any direction.
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*/
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switch (direction) {
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case DIRECTION_START:
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mFirstVisiblePosition--;
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break;
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case DIRECTION_END:
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mFirstVisiblePosition++;
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break;
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case DIRECTION_UP:
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mFirstVisiblePosition -= getTotalColumnCount();
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break;
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case DIRECTION_DOWN:
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mFirstVisiblePosition += getTotalColumnCount();
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break;
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}
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/*
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* Next, we supply the grid of items that are deemed visible.
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* If these items were previously there, they will simply be
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* re-attached. New views that must be created are obtained
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* from the Recycler and added.
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*/
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int leftOffset = startLeftOffset;
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int topOffset = startTopOffset;
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for (int i = 0; i < getVisibleChildCount(); i++) {
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int nextPosition = positionOfIndex(i);
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/*
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* When a removal happens out of bounds, the pre-layout positions of items
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* after the removal are shifted to their final positions ahead of schedule.
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* We have to track off-screen removals and shift those positions back
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* so we can properly lay out all current (and appearing) views in their
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* initial locations.
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*/
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int offsetPositionDelta = 0;
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if (state.isPreLayout()) {
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int offsetPosition = nextPosition;
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for (int offset = 0; offset < removedPositions.size(); offset++) {
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//Look for off-screen removals that are less-than this
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if (removedPositions.valueAt(offset) == REMOVE_INVISIBLE
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&& removedPositions.keyAt(offset) < nextPosition) {
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//Offset position to match
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offsetPosition--;
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}
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}
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offsetPositionDelta = nextPosition - offsetPosition;
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nextPosition = offsetPosition;
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}
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if (nextPosition < 0 || nextPosition >= state.getItemCount()) {
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//Item space beyond the data set, don't attempt to add a view
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continue;
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}
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//Layout this position
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View view = viewCache.get(nextPosition);
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if (view == null) {
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/*
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* The Recycler will give us either a newly constructed view,
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* or a recycled view it has on-hand. In either case, the
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* view will already be fully bound to the data by the
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* adapter for us.
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*/
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view = recycler.getViewForPosition(nextPosition);
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addView(view);
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/*
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* Update the new view's metadata, but only when this is a real
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* layout pass.
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*/
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if (!state.isPreLayout()) {
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LayoutParams lp = (LayoutParams) view.getLayoutParams();
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lp.row = getGlobalRowOfPosition(nextPosition);
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lp.column = getGlobalColumnOfPosition(nextPosition);
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}
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/*
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* It is prudent to measure/layout each new view we
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* receive from the Recycler. We don't have to do
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* this for views we are just re-arranging.
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*/
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measureChildWithMargins(view, 0, 0);
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layoutDecorated(view, leftOffset, topOffset,
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leftOffset + mDecoratedChildWidth,
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topOffset + mDecoratedChildHeight);
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} else {
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//Re-attach the cached view at its new index
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attachView(view);
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viewCache.remove(nextPosition);
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}
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if (i % mVisibleColumnCount == (mVisibleColumnCount - 1)) {
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leftOffset = startLeftOffset;
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topOffset += mDecoratedChildHeight;
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//During pre-layout, on each column end, apply any additional appearing views
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if (state.isPreLayout()) {
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layoutAppearingViews(recycler, view, nextPosition, removedPositions.size(), offsetPositionDelta);
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}
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} else {
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leftOffset += mDecoratedChildWidth;
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}
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}
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/*
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* Finally, we ask the Recycler to scrap and store any views
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* that we did not re-attach. These are views that are not currently
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* necessary because they are no longer visible.
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*/
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for (int i=0; i < viewCache.size(); i++) {
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final View removingView = viewCache.valueAt(i);
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recycler.recycleView(removingView);
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}
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}
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/*
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* You must override this method if you would like to support external calls
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* to shift the view to a given adapter position. In our implementation, this
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* is the same as doing a fresh layout with the given position as the top-left
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* (or first visible), so we simply set that value and trigger onLayoutChildren()
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*/
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@Override
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public void scrollToPosition(int position) {
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if (position >= getItemCount()) {
|
||||
Log.e(TAG, "Cannot scroll to "+position+", item count is "+getItemCount());
|
||||
return;
|
||||
}
|
||||
|
||||
//Set requested position as first visible
|
||||
mFirstVisiblePosition = position;
|
||||
//Toss all existing views away
|
||||
removeAllViews();
|
||||
//Trigger a new view layout
|
||||
requestLayout();
|
||||
}
|
||||
|
||||
/*
|
||||
* You must override this method if you would like to support external calls
|
||||
* to animate a change to a new adapter position. The framework provides a
|
||||
* helper scroller implementation (LinearSmoothScroller), which we leverage
|
||||
* to do the animation calculations.
|
||||
*/
|
||||
@Override
|
||||
public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state, final int position) {
|
||||
if (position >= getItemCount()) {
|
||||
Log.e(TAG, "Cannot scroll to "+position+", item count is "+getItemCount());
|
||||
return;
|
||||
}
|
||||
|
||||
/*
|
||||
* LinearSmoothScroller's default behavior is to scroll the contents until
|
||||
* the child is fully visible. It will snap to the top-left or bottom-right
|
||||
* of the parent depending on whether the direction of travel was positive
|
||||
* or negative.
|
||||
*/
|
||||
LinearSmoothScroller scroller = new LinearSmoothScroller(recyclerView.getContext()) {
|
||||
/*
|
||||
* LinearSmoothScroller, at a minimum, just need to know the vector
|
||||
* (x/y distance) to travel in order to get from the current positioning
|
||||
* to the target.
|
||||
*/
|
||||
@Override
|
||||
public PointF computeScrollVectorForPosition(int targetPosition) {
|
||||
final int rowOffset = getGlobalRowOfPosition(targetPosition)
|
||||
- getGlobalRowOfPosition(mFirstVisiblePosition);
|
||||
final int columnOffset = getGlobalColumnOfPosition(targetPosition)
|
||||
- getGlobalColumnOfPosition(mFirstVisiblePosition);
|
||||
|
||||
return new PointF(columnOffset * mDecoratedChildWidth, rowOffset * mDecoratedChildHeight);
|
||||
}
|
||||
};
|
||||
scroller.setTargetPosition(position);
|
||||
startSmoothScroll(scroller);
|
||||
}
|
||||
|
||||
/*
|
||||
* Use this method to tell the RecyclerView if scrolling is even possible
|
||||
* in the horizontal direction.
|
||||
*/
|
||||
@Override
|
||||
public boolean canScrollHorizontally() {
|
||||
//We do allow scrolling
|
||||
return true;
|
||||
}
|
||||
|
||||
/*
|
||||
* This method describes how far RecyclerView thinks the contents should scroll horizontally.
|
||||
* You are responsible for verifying edge boundaries, and determining if this scroll
|
||||
* event somehow requires that new views be added or old views get recycled.
|
||||
*/
|
||||
@Override
|
||||
public int scrollHorizontallyBy(int dx, RecyclerView.Recycler recycler, RecyclerView.State state) {
|
||||
if (getChildCount() == 0) {
|
||||
return 0;
|
||||
}
|
||||
|
||||
//Take leftmost measurements from the top-left child
|
||||
final View topView = getChildAt(0);
|
||||
//Take rightmost measurements from the top-right child
|
||||
final View bottomView = getChildAt(mVisibleColumnCount-1);
|
||||
|
||||
//Optimize the case where the entire data set is too small to scroll
|
||||
int viewSpan = getDecoratedRight(bottomView) - getDecoratedLeft(topView);
|
||||
if (viewSpan < getHorizontalSpace()) {
|
||||
//We cannot scroll in either direction
|
||||
return 0;
|
||||
}
|
||||
|
||||
int delta;
|
||||
boolean leftBoundReached = getFirstVisibleColumn() == 0;
|
||||
boolean rightBoundReached = getLastVisibleColumn() >= getTotalColumnCount();
|
||||
if (dx > 0) { // Contents are scrolling left
|
||||
//Check right bound
|
||||
if (rightBoundReached) {
|
||||
//If we've reached the last column, enforce limits
|
||||
int rightOffset = getHorizontalSpace() - getDecoratedRight(bottomView) + horizontalPadding;
|
||||
delta = Math.max(-dx, rightOffset);
|
||||
} else {
|
||||
//No limits while the last column isn't visible
|
||||
delta = -dx;
|
||||
}
|
||||
} else { // Contents are scrolling right
|
||||
//Check left bound
|
||||
if (leftBoundReached) {
|
||||
int leftOffset = -getDecoratedLeft(topView) + horizontalPadding;
|
||||
delta = Math.min(-dx, leftOffset);
|
||||
} else {
|
||||
delta = -dx;
|
||||
}
|
||||
}
|
||||
|
||||
offsetChildrenHorizontal(delta);
|
||||
|
||||
if (dx > 0) {
|
||||
if (getDecoratedRight(topView) < 0 && !rightBoundReached) {
|
||||
fillGrid(DIRECTION_END, recycler, state);
|
||||
} else if (!rightBoundReached) {
|
||||
fillGrid(DIRECTION_NONE, recycler, state);
|
||||
}
|
||||
} else {
|
||||
if (getDecoratedLeft(topView) > 0 && !leftBoundReached) {
|
||||
fillGrid(DIRECTION_START, recycler, state);
|
||||
} else if (!leftBoundReached) {
|
||||
fillGrid(DIRECTION_NONE, recycler, state);
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Return value determines if a boundary has been reached
|
||||
* (for edge effects and flings). If returned value does not
|
||||
* match original delta (passed in), RecyclerView will draw
|
||||
* an edge effect.
|
||||
*/
|
||||
return -delta;
|
||||
}
|
||||
|
||||
/*
|
||||
* Use this method to tell the RecyclerView if scrolling is even possible
|
||||
* in the vertical direction.
|
||||
*/
|
||||
@Override
|
||||
public boolean canScrollVertically() {
|
||||
//We do allow scrolling
|
||||
return true;
|
||||
}
|
||||
|
||||
/*
|
||||
* This method describes how far RecyclerView thinks the contents should scroll vertically.
|
||||
* You are responsible for verifying edge boundaries, and determining if this scroll
|
||||
* event somehow requires that new views be added or old views get recycled.
|
||||
*/
|
||||
@Override
|
||||
public int scrollVerticallyBy(int dy, RecyclerView.Recycler recycler, RecyclerView.State state) {
|
||||
if (getChildCount() == 0) {
|
||||
return 0;
|
||||
}
|
||||
|
||||
//Take top measurements from the top-left child
|
||||
final View topView = getChildAt(0);
|
||||
//Take bottom measurements from the bottom-right child.
|
||||
final View bottomView = getChildAt(getChildCount()-1);
|
||||
|
||||
//Optimize the case where the entire data set is too small to scroll
|
||||
int viewSpan = getDecoratedBottom(bottomView) - getDecoratedTop(topView);
|
||||
if (viewSpan < getVerticalSpace()) {
|
||||
//We cannot scroll in either direction
|
||||
return 0;
|
||||
}
|
||||
|
||||
int delta;
|
||||
int maxRowCount = getTotalRowCount();
|
||||
boolean topBoundReached = getFirstVisibleRow() == 0;
|
||||
boolean bottomBoundReached = getLastVisibleRow() >= maxRowCount;
|
||||
if (dy > 0) { // Contents are scrolling up
|
||||
//Check against bottom bound
|
||||
if (bottomBoundReached) {
|
||||
//If we've reached the last row, enforce limits
|
||||
int bottomOffset;
|
||||
if (rowOfIndex(getChildCount() - 1) >= (maxRowCount - 1)) {
|
||||
//We are truly at the bottom, determine how far
|
||||
bottomOffset = getVerticalSpace() - getDecoratedBottom(bottomView)
|
||||
+ verticalPadding;
|
||||
} else {
|
||||
/*
|
||||
* Extra space added to account for allowing bottom space in the grid.
|
||||
* This occurs when the overlap in the last row is not large enough to
|
||||
* ensure that at least one element in that row isn't fully recycled.
|
||||
*/
|
||||
bottomOffset = getVerticalSpace() - (getDecoratedBottom(bottomView)
|
||||
+ mDecoratedChildHeight) + verticalPadding;
|
||||
}
|
||||
|
||||
delta = Math.max(-dy, bottomOffset);
|
||||
} else {
|
||||
//No limits while the last row isn't visible
|
||||
delta = -dy;
|
||||
}
|
||||
} else { // Contents are scrolling down
|
||||
//Check against top bound
|
||||
if (topBoundReached) {
|
||||
int topOffset = -getDecoratedTop(topView) + verticalPadding;
|
||||
|
||||
delta = Math.min(-dy, topOffset);
|
||||
} else {
|
||||
delta = -dy;
|
||||
}
|
||||
}
|
||||
|
||||
offsetChildrenVertical(delta);
|
||||
|
||||
if (dy > 0) {
|
||||
if (getDecoratedBottom(topView) < 0 && !bottomBoundReached) {
|
||||
fillGrid(DIRECTION_DOWN, recycler, state);
|
||||
} else if (!bottomBoundReached) {
|
||||
fillGrid(DIRECTION_NONE, recycler, state);
|
||||
}
|
||||
} else {
|
||||
if (getDecoratedTop(topView) > 0 && !topBoundReached) {
|
||||
fillGrid(DIRECTION_UP, recycler, state);
|
||||
} else if (!topBoundReached) {
|
||||
fillGrid(DIRECTION_NONE, recycler, state);
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Return value determines if a boundary has been reached
|
||||
* (for edge effects and flings). If returned value does not
|
||||
* match original delta (passed in), RecyclerView will draw
|
||||
* an edge effect.
|
||||
*/
|
||||
return -delta;
|
||||
}
|
||||
|
||||
/*
|
||||
* This is a helper method used by RecyclerView to determine
|
||||
* if a specific child view can be returned.
|
||||
*/
|
||||
@Override
|
||||
public View findViewByPosition(int position) {
|
||||
for (int i=0; i < getChildCount(); i++) {
|
||||
if (positionOfIndex(i) == position) {
|
||||
return getChildAt(i);
|
||||
}
|
||||
}
|
||||
|
||||
return null;
|
||||
}
|
||||
|
||||
/** Boilerplate to extend LayoutParams for tracking row/column of attached views */
|
||||
|
||||
/*
|
||||
* Even without extending LayoutParams, we must override this method
|
||||
* to provide the default layout parameters that each child view
|
||||
* will receive when added.
|
||||
*/
|
||||
@Override
|
||||
public RecyclerView.LayoutParams generateDefaultLayoutParams() {
|
||||
return new LayoutParams(
|
||||
ViewGroup.LayoutParams.WRAP_CONTENT,
|
||||
ViewGroup.LayoutParams.WRAP_CONTENT);
|
||||
}
|
||||
@Override
|
||||
public RecyclerView.LayoutParams generateLayoutParams(Context c, AttributeSet attrs) {
|
||||
return new LayoutParams(c, attrs);
|
||||
}
|
||||
@Override
|
||||
public RecyclerView.LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp) {
|
||||
if (lp instanceof ViewGroup.MarginLayoutParams) {
|
||||
return new LayoutParams((ViewGroup.MarginLayoutParams) lp);
|
||||
} else {
|
||||
return new LayoutParams(lp);
|
||||
}
|
||||
}
|
||||
@Override
|
||||
public boolean checkLayoutParams(RecyclerView.LayoutParams lp) {
|
||||
return lp instanceof LayoutParams;
|
||||
}
|
||||
|
||||
public static class LayoutParams extends RecyclerView.LayoutParams {
|
||||
|
||||
//Current row in the grid
|
||||
public int row;
|
||||
//Current column in the grid
|
||||
public int column;
|
||||
|
||||
public LayoutParams(Context c, AttributeSet attrs) {
|
||||
super(c, attrs);
|
||||
}
|
||||
public LayoutParams(int width, int height) {
|
||||
super(width, height);
|
||||
}
|
||||
public LayoutParams(ViewGroup.MarginLayoutParams source) {
|
||||
super(source);
|
||||
}
|
||||
public LayoutParams(ViewGroup.LayoutParams source) {
|
||||
super(source);
|
||||
}
|
||||
public LayoutParams(RecyclerView.LayoutParams source) {
|
||||
super(source);
|
||||
}
|
||||
}
|
||||
|
||||
/** Animation Layout Helpers */
|
||||
|
||||
/* Helper to obtain and place extra appearing views */
|
||||
private void layoutAppearingViews(RecyclerView.Recycler recycler, View referenceView, int referencePosition, int extraCount, int offset) {
|
||||
//Nothing to do...
|
||||
if (extraCount < 1) return;
|
||||
|
||||
//FIXME: This code currently causes double layout of views that are still visible…
|
||||
for (int extra = 1; extra <= extraCount; extra++) {
|
||||
//Grab the next position after the reference
|
||||
final int extraPosition = referencePosition + extra;
|
||||
if (extraPosition < 0 || extraPosition >= getItemCount()) {
|
||||
//Can't do anything with this
|
||||
continue;
|
||||
}
|
||||
|
||||
/*
|
||||
* Obtain additional position views that we expect to appear
|
||||
* as part of the animation.
|
||||
*/
|
||||
View appearing = recycler.getViewForPosition(extraPosition);
|
||||
addView(appearing);
|
||||
|
||||
//Find layout delta from reference position
|
||||
final int newRow = getGlobalRowOfPosition(extraPosition + offset);
|
||||
final int rowDelta = newRow - getGlobalRowOfPosition(referencePosition + offset);
|
||||
final int newCol = getGlobalColumnOfPosition(extraPosition + offset);
|
||||
final int colDelta = newCol - getGlobalColumnOfPosition(referencePosition + offset);
|
||||
|
||||
layoutTempChildView(appearing, rowDelta, colDelta, referenceView);
|
||||
}
|
||||
}
|
||||
|
||||
/* Helper to place a disappearing view */
|
||||
private void layoutDisappearingView(View disappearingChild) {
|
||||
/*
|
||||
* LayoutManager has a special method for attaching views that
|
||||
* will only be around long enough to animate.
|
||||
*/
|
||||
addDisappearingView(disappearingChild);
|
||||
|
||||
//Adjust each disappearing view to its proper place
|
||||
final LayoutParams lp = (LayoutParams) disappearingChild.getLayoutParams();
|
||||
|
||||
final int newRow = getGlobalRowOfPosition(lp.getViewAdapterPosition());
|
||||
final int rowDelta = newRow - lp.row;
|
||||
final int newCol = getGlobalColumnOfPosition(lp.getViewAdapterPosition());
|
||||
final int colDelta = newCol - lp.column;
|
||||
|
||||
layoutTempChildView(disappearingChild, rowDelta, colDelta, disappearingChild);
|
||||
}
|
||||
|
||||
|
||||
/* Helper to lay out appearing/disappearing children */
|
||||
private void layoutTempChildView(View child, int rowDelta, int colDelta, View referenceView) {
|
||||
//Set the layout position to the global row/column difference from the reference view
|
||||
int layoutTop = getDecoratedTop(referenceView) + rowDelta * mDecoratedChildHeight;
|
||||
int layoutLeft = getDecoratedLeft(referenceView) + colDelta * mDecoratedChildWidth;
|
||||
|
||||
measureChildWithMargins(child, 0, 0);
|
||||
layoutDecorated(child, layoutLeft, layoutTop,
|
||||
layoutLeft + mDecoratedChildWidth,
|
||||
layoutTop + mDecoratedChildHeight);
|
||||
}
|
||||
|
||||
/** Private Helpers and Metrics Accessors */
|
||||
|
||||
/* Return the overall column index of this position in the global layout */
|
||||
private int getGlobalColumnOfPosition(int position) {
|
||||
return position % mTotalColumnCount;
|
||||
}
|
||||
/* Return the overall row index of this position in the global layout */
|
||||
private int getGlobalRowOfPosition(int position) {
|
||||
return position / mTotalColumnCount;
|
||||
}
|
||||
|
||||
/*
|
||||
* Mapping between child view indices and adapter data
|
||||
* positions helps fill the proper views during scrolling.
|
||||
*/
|
||||
private int positionOfIndex(int childIndex) {
|
||||
int row = childIndex / mVisibleColumnCount;
|
||||
int column = childIndex % mVisibleColumnCount;
|
||||
|
||||
return mFirstVisiblePosition + (row * getTotalColumnCount()) + column;
|
||||
}
|
||||
|
||||
private int rowOfIndex(int childIndex) {
|
||||
int position = positionOfIndex(childIndex);
|
||||
|
||||
return position / getTotalColumnCount();
|
||||
}
|
||||
|
||||
private int getFirstVisibleColumn() {
|
||||
return (mFirstVisiblePosition % getTotalColumnCount());
|
||||
}
|
||||
|
||||
private int getLastVisibleColumn() {
|
||||
return getFirstVisibleColumn() + mVisibleColumnCount;
|
||||
}
|
||||
|
||||
private int getFirstVisibleRow() {
|
||||
return (mFirstVisiblePosition / getTotalColumnCount());
|
||||
}
|
||||
|
||||
private int getLastVisibleRow() {
|
||||
return getFirstVisibleRow() + mVisibleRowCount;
|
||||
}
|
||||
|
||||
private int getVisibleChildCount() {
|
||||
return mVisibleColumnCount * mVisibleRowCount;
|
||||
}
|
||||
|
||||
private int getTotalColumnCount() {
|
||||
if (getItemCount() < mTotalColumnCount) {
|
||||
return getItemCount();
|
||||
}
|
||||
|
||||
return mTotalColumnCount;
|
||||
}
|
||||
|
||||
private int getTotalRowCount() {
|
||||
if (getItemCount() == 0 || mTotalColumnCount == 0) {
|
||||
return 0;
|
||||
}
|
||||
int maxRow = getItemCount() / mTotalColumnCount;
|
||||
//Bump the row count if it's not exactly even
|
||||
if (getItemCount() % mTotalColumnCount != 0) {
|
||||
maxRow++;
|
||||
}
|
||||
|
||||
return maxRow;
|
||||
}
|
||||
|
||||
private int getHorizontalSpace() {
|
||||
return getWidth();
|
||||
}
|
||||
|
||||
private int getVerticalSpace() {
|
||||
return getHeight();
|
||||
}
|
||||
}
|
||||
|
|
@ -0,0 +1,627 @@
|
|||
package dev.lucasnlm.antimine.common.level.widget
|
||||
|
||||
import android.content.Context
|
||||
import android.graphics.PointF
|
||||
import android.util.AttributeSet
|
||||
import android.util.Log
|
||||
import android.util.SparseArray
|
||||
import android.util.SparseIntArray
|
||||
import android.view.View
|
||||
import android.view.ViewGroup
|
||||
import android.view.ViewGroup.MarginLayoutParams
|
||||
import androidx.recyclerview.widget.LinearSmoothScroller
|
||||
import androidx.recyclerview.widget.RecyclerView
|
||||
import androidx.recyclerview.widget.RecyclerView.Recycler
|
||||
|
||||
class FixedGridLayoutManager(
|
||||
private var mTotalColumnCount: Int,
|
||||
private val horizontalPadding: Int,
|
||||
private val verticalPadding: Int
|
||||
) : RecyclerView.LayoutManager() {
|
||||
|
||||
private var mFirstVisiblePosition = 0
|
||||
|
||||
private var mDecoratedChildWidth = 0
|
||||
private var mDecoratedChildHeight = 0
|
||||
|
||||
private var mVisibleColumnCount = 0
|
||||
private var mVisibleRowCount = 0
|
||||
|
||||
private var mFirstChangedPosition = 0
|
||||
private var mChangedPositionCount = 0
|
||||
|
||||
override fun supportsPredictiveItemAnimations(): Boolean = true
|
||||
|
||||
override fun onItemsRemoved(recyclerView: RecyclerView, positionStart: Int, itemCount: Int) {
|
||||
mFirstChangedPosition = positionStart
|
||||
mChangedPositionCount = itemCount
|
||||
}
|
||||
|
||||
override fun onLayoutChildren(recycler: Recycler, state: RecyclerView.State) {
|
||||
if (itemCount == 0) {
|
||||
detachAndScrapAttachedViews(recycler)
|
||||
return
|
||||
}
|
||||
|
||||
if (childCount == 0 && state.isPreLayout) {
|
||||
return
|
||||
}
|
||||
|
||||
if (!state.isPreLayout) {
|
||||
mChangedPositionCount = 0
|
||||
mFirstChangedPosition = 0
|
||||
}
|
||||
|
||||
if (childCount == 0) {
|
||||
recycler.getViewForPosition(0).run {
|
||||
addView(this)
|
||||
measureChildWithMargins(this, 0, 0)
|
||||
|
||||
mDecoratedChildWidth = getDecoratedMeasuredWidth(this)
|
||||
mDecoratedChildHeight = getDecoratedMeasuredHeight(this)
|
||||
detachAndScrapView(this, recycler)
|
||||
}
|
||||
}
|
||||
|
||||
updateWindowSizing()
|
||||
var removedCache: SparseIntArray? = null
|
||||
|
||||
if (state.isPreLayout) {
|
||||
removedCache = SparseIntArray(childCount)
|
||||
|
||||
(0 until childCount)
|
||||
.mapNotNull { getChildAt(it) }
|
||||
.map { it.layoutParams as LayoutParams }
|
||||
.filter { it.isItemRemoved }
|
||||
.forEach { removedCache.put(it.viewLayoutPosition, REMOVE_VISIBLE) }
|
||||
|
||||
if (removedCache.size() == 0 && mChangedPositionCount > 0) {
|
||||
(mFirstChangedPosition until mFirstChangedPosition + mChangedPositionCount)
|
||||
.forEach { index ->
|
||||
removedCache.put(index, REMOVE_INVISIBLE)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
var childLeft: Int? = null
|
||||
var childTop: Int? = null
|
||||
|
||||
if (childCount == 0) {
|
||||
mFirstVisiblePosition = 0
|
||||
childLeft = horizontalPadding
|
||||
childTop = verticalPadding
|
||||
} else if (!state.isPreLayout && visibleChildCount >= state.itemCount) {
|
||||
//Data set is too small to scroll fully, just reset position
|
||||
mFirstVisiblePosition = 0
|
||||
childLeft = horizontalPadding
|
||||
childTop = verticalPadding
|
||||
} else {
|
||||
getChildAt(0)?.let { topChild ->
|
||||
childLeft = getDecoratedLeft(topChild)
|
||||
childTop = getDecoratedTop(topChild)
|
||||
}
|
||||
|
||||
if (!state.isPreLayout && verticalSpace > totalRowCount * mDecoratedChildHeight) {
|
||||
mFirstVisiblePosition %= totalColumnCount
|
||||
childTop = verticalPadding
|
||||
|
||||
if (mFirstVisiblePosition + mVisibleColumnCount > state.itemCount) {
|
||||
mFirstVisiblePosition = (state.itemCount - mVisibleColumnCount).coerceAtLeast(0)
|
||||
childLeft = horizontalPadding
|
||||
}
|
||||
}
|
||||
|
||||
val maxFirstRow = totalRowCount - (mVisibleRowCount - 1)
|
||||
val maxFirstCol = totalColumnCount - (mVisibleColumnCount - 1)
|
||||
val isOutOfRowBounds = firstVisibleRow > maxFirstRow
|
||||
val isOutOfColBounds = firstVisibleColumn > maxFirstCol
|
||||
|
||||
if (isOutOfRowBounds || isOutOfColBounds) {
|
||||
val firstRow: Int = if (isOutOfRowBounds) {
|
||||
maxFirstRow
|
||||
} else {
|
||||
firstVisibleRow
|
||||
}
|
||||
val firstCol: Int = if (isOutOfColBounds) {
|
||||
maxFirstCol
|
||||
} else {
|
||||
firstVisibleColumn
|
||||
}
|
||||
|
||||
mFirstVisiblePosition = firstRow * totalColumnCount + firstCol
|
||||
childLeft = horizontalSpace - mDecoratedChildWidth * mVisibleColumnCount
|
||||
childTop = verticalSpace - mDecoratedChildHeight * mVisibleRowCount
|
||||
|
||||
if (firstVisibleRow == 0) {
|
||||
childTop = childTop?.coerceAtMost(verticalPadding) ?: verticalSpace
|
||||
}
|
||||
if (firstVisibleColumn == 0) {
|
||||
childLeft = childLeft?.coerceAtMost(horizontalPadding) ?: horizontalSpace
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
//Clear all attached views into the recycle bin
|
||||
detachAndScrapAttachedViews(recycler)
|
||||
|
||||
//Fill the grid for the initial layout of views
|
||||
val finalChildLeft = childLeft
|
||||
val finalChildTop = childTop
|
||||
if (finalChildLeft != null && finalChildTop != null) {
|
||||
fillGrid(DIRECTION_NONE, finalChildLeft, finalChildTop, recycler, state, removedCache)
|
||||
}
|
||||
|
||||
//Evaluate any disappearing views that may exist
|
||||
if (!state.isPreLayout && recycler.scrapList.isNotEmpty()) {
|
||||
recycler.scrapList
|
||||
.map { it.itemView }
|
||||
.filterNot { (it.layoutParams as LayoutParams).isItemRemoved }
|
||||
.forEach { layoutDisappearingView(it) }
|
||||
}
|
||||
}
|
||||
|
||||
override fun onAdapterChanged(oldAdapter: RecyclerView.Adapter<*>?, newAdapter: RecyclerView.Adapter<*>?) {
|
||||
//Completely scrap the existing layout
|
||||
removeAllViews()
|
||||
}
|
||||
|
||||
private fun updateWindowSizing() {
|
||||
mVisibleColumnCount = horizontalSpace / mDecoratedChildWidth + 1
|
||||
if (horizontalSpace % mDecoratedChildWidth > 0) {
|
||||
mVisibleColumnCount++
|
||||
}
|
||||
|
||||
//Allow minimum value for small data sets
|
||||
mVisibleColumnCount = mVisibleColumnCount.coerceAtMost(totalColumnCount)
|
||||
|
||||
mVisibleRowCount = verticalSpace / mDecoratedChildHeight + 1
|
||||
if (verticalSpace % mDecoratedChildHeight > 0) {
|
||||
mVisibleRowCount++
|
||||
}
|
||||
|
||||
mVisibleRowCount.coerceAtMost(totalRowCount)
|
||||
}
|
||||
|
||||
private fun fillGrid(direction: Int, recycler: Recycler, state: RecyclerView.State) {
|
||||
fillGrid(direction, 0, 0, recycler, state, null)
|
||||
}
|
||||
|
||||
private fun fillGrid(
|
||||
direction: Int, emptyLeft: Int, emptyTop: Int,
|
||||
recycler: Recycler,
|
||||
state: RecyclerView.State,
|
||||
removedPositions: SparseIntArray?
|
||||
) {
|
||||
mFirstVisiblePosition = mFirstVisiblePosition.coerceIn(0, itemCount - 1)
|
||||
|
||||
var startLeftOffset = emptyLeft
|
||||
var startTopOffset = emptyTop
|
||||
val viewCache = SparseArray<View?>(childCount)
|
||||
|
||||
if (childCount != 0) {
|
||||
getChildAt(0)?.let { topView ->
|
||||
startLeftOffset = getDecoratedLeft(topView)
|
||||
startTopOffset = getDecoratedTop(topView)
|
||||
}
|
||||
|
||||
when (direction) {
|
||||
DIRECTION_START -> startLeftOffset -= mDecoratedChildWidth
|
||||
DIRECTION_END -> startLeftOffset += mDecoratedChildWidth
|
||||
DIRECTION_UP -> startTopOffset -= mDecoratedChildHeight
|
||||
DIRECTION_DOWN -> startTopOffset += mDecoratedChildHeight
|
||||
}
|
||||
|
||||
//Cache all views by their existing position, before updating counts
|
||||
(0 until childCount).forEach { index ->
|
||||
val position = positionOfIndex(index)
|
||||
val child = getChildAt(index)
|
||||
viewCache.put(position, child)
|
||||
}
|
||||
|
||||
//Temporarily detach all views.
|
||||
// Views we still need will be added back at the proper index.
|
||||
(0 until viewCache.size())
|
||||
.mapNotNull { index -> viewCache.valueAt(index) }
|
||||
.forEach(::detachView)
|
||||
}
|
||||
|
||||
when (direction) {
|
||||
DIRECTION_START -> mFirstVisiblePosition--
|
||||
DIRECTION_END -> mFirstVisiblePosition++
|
||||
DIRECTION_UP -> mFirstVisiblePosition -= totalColumnCount
|
||||
DIRECTION_DOWN -> mFirstVisiblePosition += totalColumnCount
|
||||
}
|
||||
|
||||
/*
|
||||
* Next, we supply the grid of items that are deemed visible.
|
||||
* If these items were previously there, they will simply be
|
||||
* re-attached. New views that must be created are obtained
|
||||
* from the Recycler and added.
|
||||
*/
|
||||
var leftOffset = startLeftOffset
|
||||
var topOffset = startTopOffset
|
||||
for (index in 0 until visibleChildCount) {
|
||||
var nextPosition = positionOfIndex(index)
|
||||
|
||||
var offsetPositionDelta = 0
|
||||
if (state.isPreLayout) {
|
||||
var offsetPosition = nextPosition
|
||||
|
||||
removedPositions?.let {
|
||||
for (offset in 0 until it.size()) {
|
||||
//Look for off-screen removals that are less-than this
|
||||
if (removedPositions.valueAt(offset) == REMOVE_INVISIBLE && removedPositions.keyAt(offset) < nextPosition) {
|
||||
//Offset position to match
|
||||
offsetPosition--
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
offsetPositionDelta = nextPosition - offsetPosition
|
||||
nextPosition = offsetPosition
|
||||
}
|
||||
|
||||
if (nextPosition < 0 || nextPosition >= state.itemCount) {
|
||||
//Item space beyond the data set, don't attempt to add a view
|
||||
continue
|
||||
}
|
||||
|
||||
//Layout this position
|
||||
var view = viewCache[nextPosition]
|
||||
if (view == null) {
|
||||
view = recycler.getViewForPosition(nextPosition)
|
||||
addView(view)
|
||||
|
||||
if (!state.isPreLayout) {
|
||||
val layoutParams = view.layoutParams as LayoutParams
|
||||
layoutParams.apply {
|
||||
row = getGlobalRowOfPosition(nextPosition)
|
||||
column = getGlobalColumnOfPosition(nextPosition)
|
||||
}
|
||||
}
|
||||
|
||||
measureChildWithMargins(view, 0, 0)
|
||||
layoutDecorated(
|
||||
view, leftOffset, topOffset,
|
||||
leftOffset + mDecoratedChildWidth,
|
||||
topOffset + mDecoratedChildHeight
|
||||
)
|
||||
} else {
|
||||
//Re-attach the cached view at its new index
|
||||
attachView(view)
|
||||
viewCache.remove(nextPosition)
|
||||
}
|
||||
|
||||
if (index % mVisibleColumnCount == mVisibleColumnCount - 1) {
|
||||
leftOffset = startLeftOffset
|
||||
topOffset += mDecoratedChildHeight
|
||||
|
||||
if (state.isPreLayout) {
|
||||
layoutAppearingViews(
|
||||
recycler,
|
||||
view,
|
||||
nextPosition,
|
||||
removedPositions?.size() ?: 0,
|
||||
offsetPositionDelta
|
||||
)
|
||||
}
|
||||
} else {
|
||||
leftOffset += mDecoratedChildWidth
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Finally, we ask the Recycler to scrap and store any views
|
||||
* that we did not re-attach. These are views that are not currently
|
||||
* necessary because they are no longer visible.
|
||||
*/for (i in 0 until viewCache.size()) {
|
||||
val removingView = viewCache.valueAt(i)
|
||||
recycler.recycleView(removingView!!)
|
||||
}
|
||||
}
|
||||
|
||||
override fun scrollToPosition(position: Int) {
|
||||
if (position >= itemCount) {
|
||||
Log.e(TAG, "Cannot scroll to $position, item count is $itemCount")
|
||||
return
|
||||
}
|
||||
|
||||
mFirstVisiblePosition = position
|
||||
removeAllViews()
|
||||
requestLayout()
|
||||
}
|
||||
|
||||
override fun smoothScrollToPosition(
|
||||
recyclerView: RecyclerView,
|
||||
state: RecyclerView.State,
|
||||
position: Int
|
||||
) {
|
||||
if (position >= itemCount) {
|
||||
Log.e(TAG, "Cannot scroll to $position, item count is $itemCount")
|
||||
return
|
||||
}
|
||||
|
||||
val scroller: LinearSmoothScroller = object : LinearSmoothScroller(recyclerView.context) {
|
||||
override fun computeScrollVectorForPosition(targetPosition: Int): PointF? {
|
||||
val rowOffset = (getGlobalRowOfPosition(targetPosition) - getGlobalRowOfPosition(mFirstVisiblePosition))
|
||||
val columnOffset = (getGlobalColumnOfPosition(targetPosition) - getGlobalColumnOfPosition(mFirstVisiblePosition))
|
||||
return PointF((columnOffset * mDecoratedChildWidth).toFloat(), (rowOffset * mDecoratedChildHeight).toFloat())
|
||||
}
|
||||
}
|
||||
scroller.targetPosition = position
|
||||
startSmoothScroll(scroller)
|
||||
}
|
||||
|
||||
override fun scrollHorizontallyBy(dx: Int, recycler: Recycler, state: RecyclerView.State): Int {
|
||||
if (childCount == 0) {
|
||||
return 0
|
||||
}
|
||||
|
||||
val topView = getChildAt(0)
|
||||
val bottomView = getChildAt(mVisibleColumnCount - 1)
|
||||
|
||||
val viewSpan = getDecoratedRight(bottomView!!) - getDecoratedLeft(topView!!)
|
||||
if (viewSpan < horizontalSpace) {
|
||||
return 0
|
||||
}
|
||||
|
||||
val leftBoundReached = firstVisibleColumn == 0
|
||||
val rightBoundReached = lastVisibleColumn >= totalColumnCount
|
||||
val delta: Int = if (dx > 0) {
|
||||
if (rightBoundReached) {
|
||||
val rightOffset = horizontalSpace - getDecoratedRight(bottomView) + horizontalPadding
|
||||
(-dx).coerceAtLeast(rightOffset)
|
||||
} else {
|
||||
-dx
|
||||
}
|
||||
} else {
|
||||
if (leftBoundReached) {
|
||||
val leftOffset = -getDecoratedLeft(topView) + horizontalPadding
|
||||
(-dx).coerceAtMost(leftOffset)
|
||||
} else {
|
||||
-dx
|
||||
}
|
||||
}
|
||||
|
||||
offsetChildrenHorizontal(delta)
|
||||
if (dx > 0) {
|
||||
if (getDecoratedRight(topView) < 0 && !rightBoundReached) {
|
||||
fillGrid(DIRECTION_END, recycler, state)
|
||||
} else if (!rightBoundReached) {
|
||||
fillGrid(DIRECTION_NONE, recycler, state)
|
||||
}
|
||||
} else {
|
||||
if (getDecoratedLeft(topView) > 0 && !leftBoundReached) {
|
||||
fillGrid(DIRECTION_START, recycler, state)
|
||||
} else if (!leftBoundReached) {
|
||||
fillGrid(DIRECTION_NONE, recycler, state)
|
||||
}
|
||||
}
|
||||
|
||||
return -delta
|
||||
}
|
||||
|
||||
override fun canScrollHorizontally(): Boolean = true
|
||||
|
||||
override fun canScrollVertically(): Boolean = true
|
||||
|
||||
override fun scrollVerticallyBy(dy: Int, recycler: Recycler, state: RecyclerView.State): Int {
|
||||
if (childCount == 0) {
|
||||
return 0
|
||||
}
|
||||
|
||||
val topView = getChildAt(0)
|
||||
val bottomView = getChildAt(childCount - 1)
|
||||
|
||||
val viewSpan = getDecoratedBottom(bottomView!!) - getDecoratedTop(topView!!)
|
||||
if (viewSpan < verticalSpace) {
|
||||
return 0
|
||||
}
|
||||
|
||||
val maxRowCount = totalRowCount
|
||||
val topBoundReached = firstVisibleRow == 0
|
||||
val bottomBoundReached = lastVisibleRow >= maxRowCount
|
||||
val delta: Int = if (dy > 0) {
|
||||
if (bottomBoundReached) {
|
||||
val bottomOffset: Int = if (rowOfIndex(childCount - 1) >= maxRowCount - 1) {
|
||||
(verticalSpace - getDecoratedBottom(bottomView) + verticalPadding)
|
||||
} else {
|
||||
verticalSpace - (getDecoratedBottom(bottomView) + mDecoratedChildHeight) + verticalPadding
|
||||
}
|
||||
(-dy).coerceAtLeast(bottomOffset)
|
||||
} else {
|
||||
-dy
|
||||
}
|
||||
} else {
|
||||
if (topBoundReached) {
|
||||
val topOffset = -getDecoratedTop(topView) + verticalPadding
|
||||
(-dy).coerceAtMost(topOffset)
|
||||
} else {
|
||||
-dy
|
||||
}
|
||||
}
|
||||
|
||||
offsetChildrenVertical(delta)
|
||||
|
||||
if (dy > 0) {
|
||||
if (getDecoratedBottom(topView) < 0 && !bottomBoundReached) {
|
||||
fillGrid(DIRECTION_DOWN, recycler, state)
|
||||
} else if (!bottomBoundReached) {
|
||||
fillGrid(DIRECTION_NONE, recycler, state)
|
||||
}
|
||||
} else {
|
||||
if (getDecoratedTop(topView) > 0 && !topBoundReached) {
|
||||
fillGrid(DIRECTION_UP, recycler, state)
|
||||
} else if (!topBoundReached) {
|
||||
fillGrid(DIRECTION_NONE, recycler, state)
|
||||
}
|
||||
}
|
||||
|
||||
return -delta
|
||||
}
|
||||
|
||||
override fun findViewByPosition(position: Int): View? =
|
||||
(0 until childCount).firstOrNull { positionOfIndex(it) == position }?.let { getChildAt(it) }
|
||||
|
||||
override fun generateDefaultLayoutParams(): RecyclerView.LayoutParams {
|
||||
return LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT)
|
||||
}
|
||||
|
||||
override fun generateLayoutParams(context: Context, attrs: AttributeSet): RecyclerView.LayoutParams {
|
||||
return LayoutParams(context, attrs)
|
||||
}
|
||||
|
||||
override fun generateLayoutParams(layoutParams: ViewGroup.LayoutParams): RecyclerView.LayoutParams {
|
||||
return if (layoutParams is MarginLayoutParams) {
|
||||
LayoutParams(layoutParams)
|
||||
} else {
|
||||
LayoutParams(layoutParams)
|
||||
}
|
||||
}
|
||||
|
||||
override fun checkLayoutParams(layoutParams: RecyclerView.LayoutParams): Boolean {
|
||||
return layoutParams is LayoutParams
|
||||
}
|
||||
|
||||
private fun layoutAppearingViews(
|
||||
recycler: Recycler,
|
||||
referenceView: View,
|
||||
referencePosition: Int,
|
||||
extraCount: Int,
|
||||
offset: Int
|
||||
) {
|
||||
if (extraCount > 1) {
|
||||
//FIXME: This code currently causes double layout of views that are still visible…
|
||||
(1..extraCount)
|
||||
.map { extra -> referencePosition + extra }
|
||||
.filterNot { extraPosition ->
|
||||
extraPosition < 0 || extraPosition >= itemCount
|
||||
}
|
||||
.forEach { extraPosition ->
|
||||
val appearing = recycler.getViewForPosition(extraPosition)
|
||||
addView(appearing)
|
||||
|
||||
val newRow = getGlobalRowOfPosition(extraPosition + offset)
|
||||
val rowDelta = newRow - getGlobalRowOfPosition(referencePosition + offset)
|
||||
val newCol = getGlobalColumnOfPosition(extraPosition + offset)
|
||||
val colDelta = newCol - getGlobalColumnOfPosition(referencePosition + offset)
|
||||
layoutTempChildView(appearing, rowDelta, colDelta, referenceView)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
private fun layoutDisappearingView(disappearingChild: View) {
|
||||
addDisappearingView(disappearingChild)
|
||||
|
||||
val layoutParams = disappearingChild.layoutParams as LayoutParams
|
||||
val newRow = getGlobalRowOfPosition(layoutParams.viewAdapterPosition)
|
||||
val rowDelta = newRow - layoutParams.row
|
||||
val newCol = getGlobalColumnOfPosition(layoutParams.viewAdapterPosition)
|
||||
val colDelta = newCol - layoutParams.column
|
||||
layoutTempChildView(disappearingChild, rowDelta, colDelta, disappearingChild)
|
||||
}
|
||||
|
||||
private fun layoutTempChildView(
|
||||
child: View,
|
||||
rowDelta: Int,
|
||||
colDelta: Int,
|
||||
referenceView: View
|
||||
) {
|
||||
val layoutTop = getDecoratedTop(referenceView) + rowDelta * mDecoratedChildHeight
|
||||
val layoutLeft = getDecoratedLeft(referenceView) + colDelta * mDecoratedChildWidth
|
||||
measureChildWithMargins(child, 0, 0)
|
||||
layoutDecorated(
|
||||
child, layoutLeft, layoutTop,
|
||||
layoutLeft + mDecoratedChildWidth,
|
||||
layoutTop + mDecoratedChildHeight
|
||||
)
|
||||
}
|
||||
|
||||
private fun getGlobalColumnOfPosition(position: Int): Int =
|
||||
position % mTotalColumnCount
|
||||
|
||||
private fun getGlobalRowOfPosition(position: Int): Int =
|
||||
position / mTotalColumnCount
|
||||
|
||||
private fun positionOfIndex(childIndex: Int): Int {
|
||||
val row = childIndex / mVisibleColumnCount
|
||||
val column = childIndex % mVisibleColumnCount
|
||||
return mFirstVisiblePosition + row * totalColumnCount + column
|
||||
}
|
||||
|
||||
private fun rowOfIndex(childIndex: Int): Int =
|
||||
positionOfIndex(childIndex) / totalColumnCount
|
||||
|
||||
private val firstVisibleColumn: Int
|
||||
get() = mFirstVisiblePosition % totalColumnCount
|
||||
|
||||
private val lastVisibleColumn: Int
|
||||
get() = firstVisibleColumn + mVisibleColumnCount
|
||||
|
||||
private val firstVisibleRow: Int
|
||||
get() = mFirstVisiblePosition / totalColumnCount
|
||||
|
||||
private val lastVisibleRow: Int
|
||||
get() = firstVisibleRow + mVisibleRowCount
|
||||
|
||||
private val visibleChildCount: Int
|
||||
get() = mVisibleColumnCount * mVisibleRowCount
|
||||
|
||||
private val totalColumnCount: Int
|
||||
get() = if (itemCount < mTotalColumnCount) {
|
||||
itemCount
|
||||
} else {
|
||||
mTotalColumnCount
|
||||
}
|
||||
|
||||
|
||||
private val totalRowCount: Int
|
||||
get() {
|
||||
return if (itemCount == 0 || mTotalColumnCount == 0) {
|
||||
0
|
||||
} else {
|
||||
val maxRow = itemCount / mTotalColumnCount
|
||||
|
||||
//Bump the row count if it's not exactly even
|
||||
if (itemCount % mTotalColumnCount != 0) {
|
||||
maxRow + 1
|
||||
} else {
|
||||
maxRow
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
private val horizontalSpace: Int
|
||||
get() = width
|
||||
|
||||
private val verticalSpace: Int
|
||||
get() = height
|
||||
|
||||
companion object {
|
||||
private val TAG = FixedGridLayoutManager::class.simpleName
|
||||
|
||||
// View Removal Constants
|
||||
private const val REMOVE_VISIBLE = 0
|
||||
private const val REMOVE_INVISIBLE = 1
|
||||
|
||||
// Fill Direction Constants
|
||||
private const val DIRECTION_NONE = -1
|
||||
private const val DIRECTION_START = 0
|
||||
private const val DIRECTION_END = 1
|
||||
private const val DIRECTION_UP = 2
|
||||
private const val DIRECTION_DOWN = 3
|
||||
}
|
||||
|
||||
class LayoutParams : RecyclerView.LayoutParams {
|
||||
//Current row in the grid
|
||||
var row = 0
|
||||
|
||||
//Current column in the grid
|
||||
var column = 0
|
||||
|
||||
constructor(c: Context?, attrs: AttributeSet?) : super(c, attrs) {}
|
||||
constructor(width: Int, height: Int) : super(width, height) {}
|
||||
constructor(source: MarginLayoutParams?) : super(source) {}
|
||||
constructor(source: ViewGroup.LayoutParams?) : super(source) {}
|
||||
}
|
||||
}
|
||||
Loading…
Reference in a new issue