Merge pull request #104 from yschimke/simpler_scroll

Simpler implementation of Wear scrolling

wearApp/src/main/java/com/surrus/peopleinspace/MainActivity.kt

@@ -34,16 +34,11 @@ class MainActivity : ComponentActivity() {
         super.onCreate(savedInstanceState)
 
         setContent {
-            val rotaryEventDispatcher = RotaryEventDispatcher()
-
             CompositionLocalProvider(
                 LocalImageLoader provides imageLoader,
-                LocalRotaryEventDispatcher provides rotaryEventDispatcher,
             ) {
                 val navController = rememberSwipeDismissableNavController()
 
-                RotaryEventHandlerSetup(rotaryEventDispatcher)
-
                 SwipeDismissableNavHost(
                     navController = navController,
                     startDestination = Screen.PersonList.route

wearApp/src/main/java/com/surrus/peopleinspace/PersonDetailsScreen.kt

@@ -23,6 +23,7 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.platform.LocalConfiguration
+import androidx.compose.ui.platform.LocalView
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
@@ -50,7 +51,6 @@ fun PersonDetailsScreen(personName: String) {
     }
 
     val scrollState = rememberScrollState()
-    RotaryEventState(scrollState)
     PersonDetailsScreen(person, scrollState)
 }
 
@@ -60,6 +60,9 @@ private fun PersonDetailsScreen(
     person: Assignment?,
     scrollState: ScrollState = rememberScrollState(),
 ) {
+    // Activate scrolling
+    LocalView.current.requestFocus()
+
     MaterialTheme {
         Scaffold(
             vignette = {
@@ -71,6 +74,7 @@ private fun PersonDetailsScreen(
         ) {
             Column(
                 modifier = Modifier
+                    .scrollHandler(scrollState)
                     .fillMaxSize()
                     .padding(horizontal = if (LocalConfiguration.current.isScreenRound) 18.dp else 8.dp)
                     .verticalScroll(scrollState),

wearApp/src/main/java/com/surrus/peopleinspace/PersonListScreen.kt

@@ -16,6 +16,7 @@ import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.wrapContentSize
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.SideEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
@@ -23,8 +24,8 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.draw.scale
 import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.platform.LocalConfiguration
 import androidx.compose.ui.platform.LocalInspectionMode
+import androidx.compose.ui.platform.LocalView
 import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.semantics.contentDescription
@@ -55,9 +56,7 @@ fun PersonListScreen(
     peopleInSpaceViewModel: PeopleInSpaceViewModel = getViewModel()
 ) {
     val peopleState by peopleInSpaceViewModel.peopleInSpace.collectAsState()
-    val scrollState = rememberScalingLazyListState()
+    PersonListScreen(peopleState, personSelected, issMapClick)
-    RotaryEventState(scrollState)
-    PersonListScreen(peopleState, personSelected, issMapClick, scrollState)
 }
 
 @OptIn(ExperimentalAnimationApi::class)
@@ -66,7 +65,6 @@ fun PersonListScreen(
     people: List<Assignment>?,
     personSelected: (person: Assignment) -> Unit,
     issMapClick: () -> Unit,
-    scrollState: ScalingLazyListState = rememberScalingLazyListState(),
 ) {
     MaterialTheme {
         AnimatedVisibility(
@@ -75,7 +73,7 @@ fun PersonListScreen(
         ) {
             if (people != null) {
                 if (people.isNotEmpty()) {
-                    PersonList(people, personSelected, issMapClick, scrollState)
+                    PersonList(people, personSelected, issMapClick)
                 } else {
                     Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
                         Card(
@@ -98,15 +96,22 @@ fun PersonList(
     issMapClick: () -> Unit,
     scrollState: ScalingLazyListState = rememberScalingLazyListState(),
 ) {
+    // Activate scrolling
+    LocalView.current.requestFocus()
+
     ScalingLazyColumn(
+        modifier = Modifier
+            .testTag(PersonListTag)
+            .scrollHandler(scrollState),
         contentPadding = PaddingValues(8.dp),
-        modifier = Modifier.testTag(PersonListTag),
         state = scrollState,
     ) {
         item {
             Row(modifier = Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.Center) {
                 Button(
-                    modifier = Modifier.size(ButtonDefaults.SmallButtonSize).wrapContentSize(),
+                    modifier = Modifier
+                        .size(ButtonDefaults.SmallButtonSize)
+                        .wrapContentSize(),
                     onClick = issMapClick
                 ) {
                     // https://www.svgrepo.com/svg/170716/international-space-station

wearApp/src/main/java/com/surrus/peopleinspace/RotaryEventDispatcher.kt

@@ -4,72 +4,37 @@ import android.view.MotionEvent
 import android.view.ViewConfiguration
 import androidx.compose.foundation.gestures.ScrollableState
 import androidx.compose.foundation.gestures.scrollBy
-import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
-import androidx.compose.runtime.SideEffect
 import androidx.compose.runtime.rememberCoroutineScope
-import androidx.compose.runtime.staticCompositionLocalOf
+import androidx.compose.ui.ExperimentalComposeUiApi
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.composed
+import androidx.compose.ui.input.pointer.RequestDisallowInterceptTouchEvent
+import androidx.compose.ui.input.pointer.pointerInteropFilter
 import androidx.compose.ui.platform.LocalContext
-import androidx.compose.ui.platform.LocalView
 import androidx.core.view.InputDeviceCompat
 import androidx.core.view.MotionEventCompat
-import androidx.core.view.ViewConfigurationCompat
 import kotlinx.coroutines.launch
 
-val LocalRotaryEventDispatcher = staticCompositionLocalOf<RotaryEventDispatcher> {
+@OptIn(ExperimentalComposeUiApi::class)
-    noLocalProvidedFor("LocalRotaryEventDispatcher")
+fun Modifier.scrollHandler(scrollState: ScrollableState): Modifier = composed {
-}
-
-/**
- * Dispatcher to link rotary event to [ScrollableState].
- * The instance should be set up by calling [RotaryEventHandlerSetup] function.
- */
-class RotaryEventDispatcher(
-    var scrollState: ScrollableState? = null
-) {
-    suspend fun onRotate(delta: Float): Float? =
-        scrollState?.scrollBy(delta)
-}
-
-/**
- * Custom rotary event setup (Currently, Column / LazyColumn doesn't handle rotary event.)
- * Refer to https://developer.android.com/training/wearables/user-input/rotary-input
- */
-@Composable
-fun RotaryEventHandlerSetup(rotaryEventDispatcher: RotaryEventDispatcher) {
-    val view = LocalView.current
     val context = LocalContext.current
     val scope = rememberCoroutineScope()
+    val scaledVerticalScrollFactor =
+        remember { ViewConfiguration.get(context).getScaledVerticalScrollFactor() }
 
-    view.requestFocus()
+    this.pointerInteropFilter(RequestDisallowInterceptTouchEvent()) { event ->
-    view.setOnGenericMotionListener { _, event ->
+        if (event.action != MotionEvent.ACTION_SCROLL ||
-        if (event?.action != MotionEvent.ACTION_SCROLL ||
             !event.isFromSource(InputDeviceCompat.SOURCE_ROTARY_ENCODER)
         ) {
-            return@setOnGenericMotionListener false
+            false
+        } else {
+            val delta = -event.getAxisValue(MotionEventCompat.AXIS_SCROLL) *
+                    scaledVerticalScrollFactor
+            scope.launch {
+                scrollState.scrollBy(delta)
+            }
+            true
         }
-
-        val delta = -event.getAxisValue(MotionEventCompat.AXIS_SCROLL) *
-            ViewConfigurationCompat.getScaledVerticalScrollFactor(
-                ViewConfiguration.get(context), context
-            )
-        scope.launch {
-            rotaryEventDispatcher.onRotate(delta)
-        }
-        true
     }
 }
-
-/**
- * Register a [ScrollableState] to [LocalRotaryEventDispatcher]
- */
-@Composable
-fun RotaryEventState(scrollState: ScrollableState?) {
-    val dispatcher = LocalRotaryEventDispatcher.current
-    SideEffect {
-        dispatcher.scrollState = scrollState
-    }
-}
-
-private fun noLocalProvidedFor(name: String): Nothing {
-    error("CompositionLocal $name not present")
-}