Fix scrolling for code blocks and clean up warnings

app/src/main/java/com/wbrawner/simplemarkdown/MarkdownApplication.java

@@ -4,10 +4,6 @@ import android.app.Application;
 import com.crashlytics.android.Crashlytics;
 import io.fabric.sdk.android.Fabric;
 
-/**
- * Created by billy on 8/22/17.
- */
-
 public class MarkdownApplication extends Application {
 
     private AppComponent component;

app/src/main/java/com/wbrawner/simplemarkdown/Utils.java

@@ -7,8 +7,10 @@ import android.preference.PreferenceManager;
 
 import com.wbrawner.simplemarkdown.view.activity.SettingsActivity;
 
+import java.io.Closeable;
 import java.io.File;
 import java.io.FilenameFilter;
+import java.io.IOException;
 import java.util.Locale;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -75,4 +77,13 @@ public class Utils {
         );
     }
 
+    public static void closeQuietly(Closeable closeable) {
+        if (closeable != null) {
+            try {
+                closeable.close();
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }
+    }
 }

app/src/main/java/com/wbrawner/simplemarkdown/model/MarkdownFile.java

@@ -1,39 +1,23 @@
 package com.wbrawner.simplemarkdown.model;
 
-import java.io.BufferedReader;
 import java.io.File;
+import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
-import java.io.FileReader;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStreamWriter;
-import java.util.Locale;
 import java.util.Scanner;
 
-import static android.content.ContentValues.TAG;
-
 /**
  * This class serves as a wrapper to manage the manage the file input and output operations, as well
  * as to keep track of the data itself in memory.
  */
 public class MarkdownFile {
-    public static final int SUCCESS = 0;
-    public static final int FILE_EXISTS = 1;
-    public static final int FILE_NOT_EXISTS = 2;
-    public static final int READ_ERROR = 3;
-    public static final int WRITE_ERROR = 4;
-    public static final int PARAMETERS_MISSING = 5;
-
-    public static void setDefaultRootDir(String defaultRootDir) {
-        MarkdownFile.defaultRootDir = defaultRootDir;
-    }
-
     private static String defaultRootDir = "";
     private String name;
     private String path;
     private String content;
-
     public MarkdownFile(String name, String path, String content) {
         this.name = name;
         if (path == null || path.isEmpty()) {
@@ -44,8 +28,7 @@ public class MarkdownFile {
     }
 
     public MarkdownFile(String path) {
-        int code = load(path);
+        if (load(path)) {
-        if (code != SUCCESS) {
             this.name = path.substring(
                     path.lastIndexOf("/") + 1
             );
@@ -63,6 +46,10 @@ public class MarkdownFile {
         this.content = "";
     }
 
+    public static void setDefaultRootDir(String defaultRootDir) {
+        MarkdownFile.defaultRootDir = defaultRootDir;
+    }
+
     public String getName() {
         return name;
     }
@@ -75,6 +62,10 @@ public class MarkdownFile {
         return path;
     }
 
+    public void setPath(String path) {
+        this.path = path;
+    }
+
     public String getFullPath() {
         String fullPath;
 
@@ -95,10 +86,6 @@ public class MarkdownFile {
         return fullPath + this.name;
     }
 
-    public void setPath(String path) {
-        this.path = path;
-    }
-
     public String getContent() {
         return content;
     }
@@ -107,61 +94,46 @@ public class MarkdownFile {
         this.content = content;
     }
 
-    public int load(InputStream in) {
+    public boolean load(InputStream in) {
         StringBuilder sb = new StringBuilder();
         Scanner s = new java.util.Scanner(in).useDelimiter("\\n");
+        if (s == null) {
+            return false;
+        }
         while (s.hasNext()) {
-            sb.append(s.next() + "\n");
+            sb.append(s.next()).append("\n");
         }
         this.content = sb.toString();
-        return SUCCESS;
+        try {
+            in.close();
+        } catch (Exception ignored) {
+        }
+        return true;
     }
 
-    public int load(String path) {
+    private boolean load(String path) {
         return load(new File(path));
     }
 
-    public int load(File markdownFile) {
+    private boolean load(File markdownFile) {
-        int code;
+        if (!markdownFile.exists() || !markdownFile.canRead()) {
-        if (markdownFile.exists() && markdownFile.canRead()) {
+            return false;
-            BufferedReader reader = null;
+        }
-            try {
+
-                this.name = markdownFile.getName();
+        try {
-                this.path = markdownFile.getParentFile().getAbsolutePath();
+            this.name = markdownFile.getName();
-
+            this.path = markdownFile.getParentFile().getAbsolutePath();
-                StringBuilder sb = new StringBuilder();
+            return load(new FileInputStream(markdownFile));
-                String line;
+        } catch (FileNotFoundException e) {
-                reader = new BufferedReader(new FileReader(markdownFile));
+            return false;
-                while ((line = reader.readLine()) != null)
-                    sb.append(line + "\n");
-                this.content = sb.toString();
-                code = SUCCESS;
-            } catch (FileNotFoundException e) {
-                code = FILE_NOT_EXISTS;
-            } catch (IOException e) {
-                code = READ_ERROR;
-            }
-            if (reader != null) {
-                try {
-                    reader.close();
-                } catch (IOException e) {
-                    // closing the reader failed
-                }
-            }
-        } else {
-            code = READ_ERROR;
         }
-        return code;
     }
 
-    public int load() {
+    public boolean load() {
-        if (this.name.isEmpty())
+        return !this.name.isEmpty() && load(getFullPath());
-            return PARAMETERS_MISSING;
-        return load(getFullPath());
     }
 
-    public int save(String path) {
+    public boolean save(String path) {
-        int code;
         if (path == null) {
             path = this.getFullPath();
         }
@@ -169,23 +141,28 @@ public class MarkdownFile {
         File markdownFile = new File(path);
         if (!markdownFile.exists()) {
             try {
-                markdownFile.createNewFile();
+                if (!markdownFile.createNewFile()) {
+                    return false;
+                }
             } catch (IOException e) {
                 e.printStackTrace();
-                return WRITE_ERROR;
+                return false;
             }
         }
-        if (markdownFile.canWrite()) {
+
-            OutputStreamWriter writer = null;
+        if (!markdownFile.canWrite()) {
-            try {
+            return false;
-                writer = new OutputStreamWriter(
+        }
-                        new FileOutputStream(markdownFile)
+
-                );
+        OutputStreamWriter writer = null;
-                writer.write(this.content);
+        try {
-                code = SUCCESS;
+            writer = new OutputStreamWriter(
-            } catch (IOException e) {
+                    new FileOutputStream(markdownFile)
-                code = WRITE_ERROR;
+            );
-            }
+            writer.write(this.content);
+        } catch (IOException e) {
+            return false;
+        } finally {
             if (writer != null) {
                 try {
                     writer.close();
@@ -193,11 +170,10 @@ public class MarkdownFile {
                     // closing the reader failed
                 }
             }
-        } else {
-            code = WRITE_ERROR;
         }
+
         this.name = markdownFile.getName();
         this.path = markdownFile.getParentFile().getAbsolutePath();
-        return code;
+        return true;
     }
 }

app/src/main/java/com/wbrawner/simplemarkdown/presentation/MarkdownPresenter.java

@@ -16,7 +16,8 @@ public interface MarkdownPresenter {
     void loadMarkdown(InputStream in);
     void loadMarkdown(File file);
     void loadFromUri(Context context, Uri fileUri);
-    void loadTempMarkdown(InputStream in, OnTempFileLoadedListener listener);
+
+    void loadMarkdown(InputStream in, OnTempFileLoadedListener listener);
     void newFile(String path);
     void setEditView(MarkdownEditView editView);
     void setPreviewView(MarkdownPreviewView previewView);
@@ -31,12 +32,13 @@ public interface MarkdownPresenter {
     String getMarkdown();
     void setMarkdown(String markdown);
 
-    abstract class OnTempFileLoadedListener {
+    interface OnTempFileLoadedListener {
-        public abstract void onSuccess(String markdown);
+        void onSuccess(String markdown);
-        public abstract void onError(int code);
+
+        void onError();
     }
 
     interface MarkdownSavedListener {
-        void saveComplete();
+        void saveComplete(boolean success);
     }
 }

app/src/main/java/com/wbrawner/simplemarkdown/presentation/MarkdownPresenterImpl.java

@@ -5,25 +5,22 @@ import android.database.Cursor;
 import android.net.Uri;
 import android.os.Handler;
 import android.provider.OpenableColumns;
-import android.util.Log;
 
 import com.commonsware.cwac.anddown.AndDown;
+import com.wbrawner.simplemarkdown.Utils;
 import com.wbrawner.simplemarkdown.model.MarkdownFile;
 import com.wbrawner.simplemarkdown.view.MarkdownEditView;
 import com.wbrawner.simplemarkdown.view.MarkdownPreviewView;
 
 import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
 import java.io.InputStream;
 
 public class MarkdownPresenterImpl implements MarkdownPresenter {
     private MarkdownFile file;
     private MarkdownEditView editView;
     private MarkdownPreviewView previewView;
-    private String TAG = MarkdownPresenterImpl.class.getSimpleName();
-    private int HOEDOWN_FLAGS =
-            AndDown.HOEDOWN_EXT_STRIKETHROUGH | AndDown.HOEDOWN_EXT_TABLES |
-                    AndDown.HOEDOWN_EXT_UNDERLINE | AndDown.HOEDOWN_EXT_SUPERSCRIPT |
-                    AndDown.HOEDOWN_EXT_FENCED_CODE;
     private Handler fileHandler = new Handler();
 
     public MarkdownPresenterImpl(MarkdownFile file) {
@@ -44,14 +41,12 @@ public class MarkdownPresenterImpl implements MarkdownPresenter {
     @Override
     public void loadMarkdown() {
         Runnable fileLoader = () -> {
-            int result = this.file.load();
+            boolean result = this.file.load();
+
             if (editView != null) {
-                if (result == MarkdownFile.SUCCESS) {
+                editView.onFileLoaded(result);
-                    editView.setMarkdown(getMarkdown());
+                editView.setMarkdown(getMarkdown());
-                    onMarkdownEdited();
+                onMarkdownEdited();
-                } else {
-                    editView.showFileLoadeddError(result);
-                }
             }
         };
         fileHandler.post(fileLoader);
@@ -59,47 +54,36 @@ public class MarkdownPresenterImpl implements MarkdownPresenter {
 
     @Override
     public void loadMarkdown(File file) {
-        Runnable fileLoader = () -> {
+        InputStream in = null;
-            int result = this.file.load(file);
+        try {
-            if (editView != null) {
+            in = new FileInputStream(file);
-                if (result == MarkdownFile.SUCCESS) {
+            loadMarkdown(in);
-                    editView.setTitle(this.file.getName());
+        } catch (FileNotFoundException e) {
-                    editView.setMarkdown(getMarkdown());
+            System.err.println(e.getLocalizedMessage());
-                    onMarkdownEdited();
+            e.printStackTrace();
-                } else {
+        } finally {
-                    editView.showFileLoadeddError(result);
+            Utils.closeQuietly(in);
-                }
+        }
-            }
-        };
-        fileHandler.post(fileLoader);
     }
 
     @Override
     public void loadMarkdown(InputStream in) {
-        Runnable fileLoader = () -> {
+        this.loadMarkdown(in, null);
-            int result = file.load(in);
-            if (result == MarkdownFile.SUCCESS) {
-                if (editView != null)
-                    editView.setMarkdown(getMarkdown());
-                onMarkdownEdited();
-            } else {
-                if (editView != null)
-                    editView.showFileLoadeddError(result);
-            }
-        };
-        fileHandler.post(fileLoader);
     }
 
     @Override
-    public void loadTempMarkdown(InputStream in, OnTempFileLoadedListener listener) {
+    public void loadMarkdown(final InputStream in, final OnTempFileLoadedListener listener) {
         Runnable fileLoader = () -> {
             MarkdownFile tmpFile = new MarkdownFile();
-            int result = tmpFile.load(in);
+            if (tmpFile.load(in)) {
-            if (result == MarkdownFile.SUCCESS) {
                 String html = generateHTML(tmpFile.getContent());
-                listener.onSuccess(html);
+                if (listener != null) {
+                    listener.onSuccess(html);
+                }
             } else {
-                listener.onError(result);
+                if (listener != null) {
+                    listener.onError();
+                }
             }
         };
         fileHandler.post(fileLoader);
@@ -128,19 +112,12 @@ public class MarkdownPresenterImpl implements MarkdownPresenter {
     @Override
     public void saveMarkdown(MarkdownSavedListener listener, String filePath) {
         Runnable fileSaver = () -> {
-            int code;
+            boolean result = file.save(filePath);
-            code = file.save(filePath);
-
             if (listener != null) {
-                listener.saveComplete();
+                listener.saveComplete(result);
             }
-
             if (editView != null) {
-                if (code == MarkdownFile.SUCCESS) {
+                editView.onFileSaved(result);
-                    editView.showFileSavedMessage();
-                } else {
-                    editView.showFileSavedError(code);
-                }
             }
         };
         fileHandler.post(fileSaver);
@@ -164,6 +141,9 @@ public class MarkdownPresenterImpl implements MarkdownPresenter {
     @Override
     public String generateHTML(String markdown) {
         AndDown andDown = new AndDown();
+        int HOEDOWN_FLAGS = AndDown.HOEDOWN_EXT_STRIKETHROUGH | AndDown.HOEDOWN_EXT_TABLES |
+                AndDown.HOEDOWN_EXT_UNDERLINE | AndDown.HOEDOWN_EXT_SUPERSCRIPT |
+                AndDown.HOEDOWN_EXT_FENCED_CODE;
         return andDown.markdownToHtml(markdown, HOEDOWN_FLAGS, 0);
     }
 
@@ -210,14 +190,16 @@ public class MarkdownPresenterImpl implements MarkdownPresenter {
                             .getColumnIndex(OpenableColumns.DISPLAY_NAME);
                     retCur.moveToFirst();
                     setFileName(retCur.getString(nameIndex));
+                    retCur.close();
                 }
             } else if (fileUri.getScheme().equals("file")) {
                 setFileName(fileUri.getLastPathSegment());
             }
             loadMarkdown(in);
         } catch (Exception e) {
-            if (editView != null)
+            if (editView != null) {
-                editView.showFileLoadeddError(MarkdownFile.READ_ERROR);
+                editView.onFileLoaded(false);
+            }
         }
     }
 }

app/src/main/java/com/wbrawner/simplemarkdown/view/DisableableViewPager.java

@@ -0,0 +1,36 @@
+package com.wbrawner.simplemarkdown.view;
+
+import android.annotation.SuppressLint;
+import android.content.Context;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.support.v4.view.ViewPager;
+import android.util.AttributeSet;
+import android.view.MotionEvent;
+
+public class DisableableViewPager extends ViewPager {
+    private boolean isSwipeLocked = false;
+
+    public DisableableViewPager(@NonNull Context context) {
+        super(context);
+    }
+
+    public DisableableViewPager(@NonNull Context context, @Nullable AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    @Override
+    public boolean onInterceptTouchEvent(MotionEvent ev) {
+        return !isSwipeLocked && super.onInterceptTouchEvent(ev);
+    }
+
+    @SuppressLint("ClickableViewAccessibility")
+    @Override
+    public boolean onTouchEvent(MotionEvent ev) {
+        return !isSwipeLocked && super.onTouchEvent(ev);
+    }
+
+    public void setSwipeLocked(boolean locked) {
+        this.isSwipeLocked = locked;
+    }
+}

app/src/main/java/com/wbrawner/simplemarkdown/view/MarkdownEditView.java

@@ -1,11 +1,13 @@
 package com.wbrawner.simplemarkdown.view;
 
+import java.io.File;
+
 public interface MarkdownEditView {
     String getMarkdown();
     void setMarkdown(String markdown);
     void setTitle(String title);
-    void showFileSavedMessage();
+
-    void showFileSavedError(int code);
+    void onFileSaved(boolean success);
-    void showFileLoadedMessage();
+
-    void showFileLoadeddError(int code);
+    void onFileLoaded(boolean success);
 }

app/src/main/java/com/wbrawner/simplemarkdown/view/activity/MainActivity.java

@@ -3,12 +3,13 @@ package com.wbrawner.simplemarkdown.view.activity;
 import android.Manifest;
 import android.content.Intent;
 import android.content.pm.PackageManager;
+import android.content.res.AssetManager;
 import android.content.res.Configuration;
 import android.os.Build;
+import android.support.annotation.NonNull;
 import android.support.design.widget.TabLayout;
 import android.support.v4.app.ActivityCompat;
 import android.support.v4.content.ContextCompat;
-import android.support.v4.view.ViewPager;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.view.Menu;
@@ -20,6 +21,7 @@ import com.wbrawner.simplemarkdown.MarkdownApplication;
 import com.wbrawner.simplemarkdown.R;
 import com.wbrawner.simplemarkdown.Utils;
 import com.wbrawner.simplemarkdown.presentation.MarkdownPresenter;
+import com.wbrawner.simplemarkdown.view.DisableableViewPager;
 import com.wbrawner.simplemarkdown.view.adapter.EditPagerAdapter;
 
 import java.io.File;
@@ -39,17 +41,15 @@ public class MainActivity extends AppCompatActivity
     static final String EXTRA_FILE = "EXTRA_FILE";
     static final String EXTRA_FILE_PATH = "EXTRA_FILE_PATH";
     static final String EXTRA_REQUEST_CODE = "EXTRA_REQUEST_CODE";
-    public static final String AUTHORITY = "com.wbrawner.simplemarkdown.fileprovider";
 
     @Inject
     MarkdownPresenter presenter;
 
     @BindView(R.id.pager)
-    ViewPager pager;
+    DisableableViewPager pager;
     @BindView(R.id.layout_tab)
     TabLayout tabLayout;
 
-    private static final String TAG = MainActivity.class.getSimpleName();
     private NewFileHandler newFileHandler;
 
     @Override
@@ -140,6 +140,10 @@ public class MainActivity extends AppCompatActivity
             case R.id.action_new:
                 presenter.saveMarkdown(newFileHandler, null);
                 break;
+            case R.id.action_lock_swipe:
+                item.setChecked(!item.isChecked());
+                pager.setSwipeLocked(item.isChecked());
+                break;
             case R.id.action_help:
                 showInfoActivity(R.id.action_help);
                 break;
@@ -171,8 +175,11 @@ public class MainActivity extends AppCompatActivity
         infoIntent.putExtra("title", title);
         InputStream in = null;
         try {
-            in = getAssets().open(fileName);
+            AssetManager assetManager = getAssets();
-            presenter.loadTempMarkdown(in, new MarkdownPresenter.OnTempFileLoadedListener() {
+            if (assetManager != null) {
+                in = assetManager.open(fileName);
+            }
+            presenter.loadMarkdown(in, new MarkdownPresenter.OnTempFileLoadedListener() {
                 @Override
                 public void onSuccess(String html) {
                     infoIntent.putExtra("html", html);
@@ -180,7 +187,7 @@ public class MainActivity extends AppCompatActivity
                 }
 
                 @Override
-                public void onError(int code) {
+                public void onError() {
                     Toast.makeText(MainActivity.this, R.string.file_load_error, Toast.LENGTH_SHORT)
                             .show();
                 }
@@ -188,17 +195,14 @@ public class MainActivity extends AppCompatActivity
         } catch (Exception e) {
             Toast.makeText(MainActivity.this, R.string.file_load_error, Toast.LENGTH_SHORT).show();
         }
-        if (in != null) {
-            try {
-                in.close();
-            } catch (Exception e) {
-            }
-        }
     }
 
     @Override
-    public void onRequestPermissionsResult(int requestCode,
+    public void onRequestPermissionsResult(
-                                           String permissions[], int[] grantResults) {
+            int requestCode,
+            @NonNull String permissions[],
+            @NonNull int[] grantResults
+    ) {
         switch (requestCode) {
             case WRITE_PERMISSION_REQUEST: {
                 // If request is cancelled, the result arrays are empty.
@@ -293,9 +297,17 @@ public class MainActivity extends AppCompatActivity
 
     private class NewFileHandler implements MarkdownPresenter.MarkdownSavedListener {
         @Override
-        public void saveComplete() {
+        public void saveComplete(boolean success) {
-            String newFile = Utils.getDefaultFileName(MainActivity.this);
+            if (success) {
-            presenter.newFile(newFile);
+                String newFile = Utils.getDefaultFileName(MainActivity.this);
+                presenter.newFile(newFile);
+            } else {
+                Toast.makeText(
+                        MainActivity.this,
+                        R.string.file_save_error,
+                        Toast.LENGTH_SHORT
+                ).show();
+            }
         }
     }
 }

app/src/main/java/com/wbrawner/simplemarkdown/view/activity/MarkdownInfoActivity.java

@@ -1,15 +1,13 @@
 package com.wbrawner.simplemarkdown.view.activity;
 
 import android.content.Intent;
-import android.graphics.drawable.ColorDrawable;
 import android.support.v7.app.ActionBar;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
-import android.view.View;
-import android.webkit.WebSettings;
 import android.webkit.WebView;
 
 import com.wbrawner.simplemarkdown.R;
+import com.wbrawner.simplemarkdown.view.fragment.PreviewFragment;
 
 import butterknife.BindView;
 import butterknife.ButterKnife;
@@ -24,15 +22,19 @@ public class MarkdownInfoActivity extends AppCompatActivity {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_markdown_info);
         ButterKnife.bind(this);
-        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
+        ActionBar supportActionBar = getSupportActionBar();
+        if (supportActionBar != null) {
+            supportActionBar.setDisplayHomeAsUpEnabled(true);
+        }
         Intent intent = getIntent();
-        if (intent == null || !intent.hasExtra("title") || !intent.hasExtra("html"))
+        if (intent == null || !intent.hasExtra("title") || !intent.hasExtra("html")) {
             finish();
+            return;
+        }
         setTitle(intent.getStringExtra("title"));
-        String style = "<style>pre {overflow:scroll;}</style>";
         infoWebview.loadDataWithBaseURL(
                 null,
-                style + intent.getStringExtra("html"),
+                PreviewFragment.style + intent.getStringExtra("html"),
                 "text/html",
                 "UTF-8",
                 null

app/src/main/java/com/wbrawner/simplemarkdown/view/fragment/EditFragment.java

@@ -1,7 +1,8 @@
 package com.wbrawner.simplemarkdown.view.fragment;
 
-import android.app.AlertDialog;
+import android.app.Activity;
 import android.os.Bundle;
+import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.v4.app.Fragment;
 import android.view.LayoutInflater;
@@ -14,7 +15,6 @@ import com.jakewharton.rxbinding2.widget.RxTextView;
 import com.wbrawner.simplemarkdown.MarkdownApplication;
 import com.wbrawner.simplemarkdown.R;
 import com.wbrawner.simplemarkdown.Utils;
-import com.wbrawner.simplemarkdown.model.MarkdownFile;
 import com.wbrawner.simplemarkdown.presentation.MarkdownPresenter;
 import com.wbrawner.simplemarkdown.view.MarkdownEditView;
 
@@ -30,40 +30,36 @@ import io.reactivex.android.schedulers.AndroidSchedulers;
 import io.reactivex.schedulers.Schedulers;
 
 public class EditFragment extends Fragment implements MarkdownEditView {
-    public static final String SAVE_ACTION = "com.wbrawner.simplemarkdown.ACTION_SAVE";
-    public static final String LOAD_ACTION = "com.wbrawner.simplemarkdown.ACTION_LOAD";
-    private String TAG = EditFragment.class.getSimpleName();
-    private Unbinder unbinder;
-
     @Inject
     MarkdownPresenter presenter;
-
     @BindView(R.id.markdown_edit)
     EditText markdownEditor;
+    private Unbinder unbinder;
 
     public EditFragment() {
         // Required empty public constructor
     }
 
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
         // Inflate the layout for this fragment
         View view = inflater.inflate(R.layout.fragment_edit, container, false);
         unbinder = ButterKnife.bind(this, view);
-        ((MarkdownApplication) getActivity().getApplication()).getComponent().inject(this);
+        Activity activity = getActivity();
+        if (activity != null) {
+            ((MarkdownApplication) activity.getApplication()).getComponent().inject(this);
+        }
         Observable<String> obs = RxTextView.textChanges(markdownEditor)
                 .debounce(50, TimeUnit.MILLISECONDS).map(CharSequence::toString);
         obs.subscribeOn(Schedulers.io());
         obs.observeOn(AndroidSchedulers.mainThread());
-        obs.subscribe(markdown -> {
+        obs.subscribe(markdown -> presenter.onMarkdownEdited(markdown));
-            presenter.onMarkdownEdited(markdown);
-        });
         return view;
     }
 
     @Override
-    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
         presenter.setEditView(EditFragment.this);
         presenter.loadMarkdown();
@@ -87,47 +83,37 @@ public class EditFragment extends Fragment implements MarkdownEditView {
         return markdownEditor.getText().toString();
     }
 
+    @Override
+    public void setMarkdown(String markdown) {
+        markdownEditor.setText(markdown);
+    }
+
     @Override
     public void setTitle(String title) {
-        getActivity().setTitle(title);
+        Activity activity = getActivity();
+        if (activity != null) {
+            activity.setTitle(title);
+        }
     }
 
     @Override
-    public void showFileSavedMessage() {
+    public void onFileSaved(boolean success) {
         String location = Utils.getDocsPath(getActivity()) + presenter.getFileName();
-        String message = getString(R.string.file_saved, location);
+        String message;
-        Toast.makeText(getActivity(), message, Toast.LENGTH_SHORT).show();
+        if (success) {
-    }
+            message = getString(R.string.file_saved, location);
-
+        } else {
-    @Override
+            message = getString(R.string.file_save_error);
-    public void showFileSavedError(int code) {
-        String message = "";
-        switch (code) {
-            case MarkdownFile.WRITE_ERROR:
-                message = getString(R.string.error_write);
-                break;
-            default:
-                message = getString(R.string.file_save_error);
         }
         Toast.makeText(getActivity(), message, Toast.LENGTH_SHORT).show();
     }
 
     @Override
-    public void showFileLoadedMessage() {
+    public void onFileLoaded(boolean success) {
-        Toast.makeText(getActivity(), R.string.file_loaded, Toast.LENGTH_SHORT).show();
+        int message = success ? R.string.file_loaded : R.string.file_load_error;
-    }
-
-    @Override
-    public void showFileLoadeddError(int code) {
-        String message = "";
         Toast.makeText(getActivity(), message, Toast.LENGTH_SHORT).show();
     }
 
-    @Override
-    public void setMarkdown(String markdown) {
-        markdownEditor.setText(markdown);
-    }
-
     @Override
     public void onDestroyView() {
         super.onDestroyView();

app/src/main/java/com/wbrawner/simplemarkdown/view/fragment/PreviewFragment.java

@@ -1,6 +1,8 @@
 package com.wbrawner.simplemarkdown.view.fragment;
 
+import android.app.Activity;
 import android.os.Bundle;
+import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.v4.app.Fragment;
 import android.view.LayoutInflater;
@@ -22,32 +24,39 @@ import butterknife.Unbinder;
 
 public class PreviewFragment extends Fragment implements MarkdownPreviewView {
     private static final String TAG = PreviewFragment.class.getSimpleName();
-    private Unbinder unbinder;
+    public static String style = "<style>" +
-
+            "pre {overflow:scroll; padding:15px; background: #F1F1F1;}" +
+            "</style>";
     @Inject
     MarkdownPresenter presenter;
-
     @BindView(R.id.markdown_view)
     WebView markdownPreview;
+    private Unbinder unbinder;
 
     public PreviewFragment() {
         // Required empty public constructor
     }
 
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public View onCreateView(
-                             Bundle savedInstanceState) {
+            @NonNull LayoutInflater inflater,
+            ViewGroup container,
+            Bundle savedInstanceState
+    ) {
         // Inflate the layout for this fragment
         View view = inflater.inflate(R.layout.fragment_preview, container, false);
         unbinder = ButterKnife.bind(this, view);
-        ((MarkdownApplication) getActivity().getApplication()).getComponent().inject(this);
+        Activity activity = getActivity();
+        if (activity != null) {
+            ((MarkdownApplication) activity.getApplication()).getComponent().inject(this);
+        }
         if (BuildConfig.DEBUG)
             WebView.setWebContentsDebuggingEnabled(true);
         return view;
     }
 
     @Override
-    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
     }
 
@@ -56,9 +65,13 @@ public class PreviewFragment extends Fragment implements MarkdownPreviewView {
     @Override
     public void updatePreview(String html) {
         if (markdownPreview != null) {
-            markdownPreview.post(() -> {
+            markdownPreview.post(() -> markdownPreview.loadDataWithBaseURL(
-                markdownPreview.loadDataWithBaseURL(null, html, "text/html", "UTF-8", null);
+                    null,
-            });
+                    style + html,
+                    "text/html",
+                    "UTF-8",
+                    null
+            ));
         }
     }
 

app/src/main/res/layout/activity_main.xml

@@ -3,26 +3,27 @@
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent">
-    <android.support.v4.view.ViewPager
+
+    <com.wbrawner.simplemarkdown.view.DisableableViewPager
         android:id="@+id/pager"
         android:layout_width="match_parent"
         android:layout_height="match_parent">
         <android.support.design.widget.TabLayout
+            android:id="@+id/layout_tab"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
-            android:id="@+id/layout_tab"
             android:layout_gravity="top">
             <android.support.design.widget.TabItem
+                android:id="@+id/tab_edit"
                 android:layout_width="0dp"
                 android:layout_height="wrap_content"
-                android:text="@string/action_edit"
+                android:text="@string/action_edit" />
-                android:id="@+id/tab_edit" />
             <android.support.design.widget.TabItem
+                android:id="@+id/tab_preview"
                 android:layout_width="0dp"
                 android:layout_height="wrap_content"
-                android:text="@string/action_preview"
+                android:text="@string/action_preview" />
-                android:id="@+id/tab_preview" />
         </android.support.design.widget.TabLayout>
-    </android.support.v4.view.ViewPager>
+    </com.wbrawner.simplemarkdown.view.DisableableViewPager>
 
 </LinearLayout>

app/src/main/res/menu/menu_edit.xml

@@ -2,38 +2,38 @@
 <menu xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto">
     <item
-        android:title="@string/action_share"
         android:id="@+id/action_share"
         android:icon="@drawable/ic_action_share"
+        android:title="@string/action_share"
         app:showAsAction="ifRoom" />
     <item
-        android:title="@string/action_save"
         android:id="@+id/action_save"
         android:icon="@drawable/ic_action_save"
+        android:title="@string/action_save"
         app:showAsAction="never" />
     <item
         android:id="@+id/action_load"
-        android:orderInCategory="100"
         android:title="@string/action_open"
         app:showAsAction="never" />
     <item
         android:id="@+id/action_new"
-        android:orderInCategory="150"
         android:title="@string/action_new"
         app:showAsAction="never" />
+    <item
+        android:id="@+id/action_lock_swipe"
+        android:checkable="true"
+        android:title="@string/action_lock_swipe"
+        app:showAsAction="never" />
     <item
         android:id="@+id/action_settings"
-        android:orderInCategory="200"
         android:title="@string/action_settings"
         app:showAsAction="never" />
     <item
         android:id="@+id/action_help"
-        android:orderInCategory="200"
         android:title="@string/action_help"
         app:showAsAction="never" />
     <item
         android:id="@+id/action_libraries"
-        android:orderInCategory="300"
         android:title="@string/action_libraries"
         app:showAsAction="never" />
 </menu>

app/src/main/res/values/strings.xml

@@ -32,4 +32,5 @@
     <string name="title_activity_settings">Settings</string>
     <string name="pref_title_autosave">Enable autosave</string>
     <string name="pref_description_autosave">Automatically save files when closing the app</string>
+    <string name="action_lock_swipe">Lock Swiping</string>
 </resources>