Add predictive back animation for all fragments

app/src/main/java/dev/brahmkshatriya/echo/offline/OfflineExtension.kt

@@ -357,8 +357,8 @@ class OfflineExtension(
     override suspend fun searchTabs(query: String) =
         listOf("All", "Tracks", "Albums", "Artists").map { Tab(it, it) }
 
-    override fun searchFeed(query: String?, tab: Tab?) = run {
-        query ?: return@run emptyList()
+    override fun searchFeed(query: String, tab: Tab?) = run {
+        query.ifBlank { return@run emptyList() }
         saveInHistory(query)
         val tracks = library.songList.map { it }.searchBy(query) {
             listOf(it.title, it.album?.title) + it.artists.map { artist -> artist.name }

app/src/main/java/dev/brahmkshatriya/echo/ui/paging/ContinuationSource.kt

@@ -4,13 +4,13 @@ import androidx.paging.PagingConfig
 import androidx.paging.PagingState
 import dev.brahmkshatriya.echo.common.helpers.Page
 
-class ContinuationSource<C : Any, P : Any>(
-    private val load: suspend (token: P?) -> Page<C, P?>,
-    private val invalidate: (token: P?) -> Unit
-) : ErrorPagingSource<P, C>() {
+class ContinuationSource<C : Any>(
+    private val load: suspend (token: String?) -> Page<C>,
+    private val invalidate: (token: String?) -> Unit
+) : ErrorPagingSource<String, C>() {
 
     override val config = PagingConfig(pageSize = 10, enablePlaceholders = false)
-    override suspend fun loadData(params: LoadParams<P>): LoadResult.Page<P, C> {
+    override suspend fun loadData(params: LoadParams<String>): LoadResult.Page<String, C> {
         val token = params.key
         val page = load(token)
         return LoadResult.Page(
@@ -20,8 +20,8 @@ class ContinuationSource<C : Any, P : Any>(
         )
     }
 
-    override fun getRefreshKey(state: PagingState<P, C>) = state.anchorPosition?.let { position ->
-        state.closestPageToPosition(position)?.nextKey?.let { key ->
+    override fun getRefreshKey(state: PagingState<String, C>) = state.anchorPosition?.let { pos ->
+        state.closestPageToPosition(pos)?.nextKey?.let { key ->
             invalidate(key)
             key
         }

app/src/main/java/dev/brahmkshatriya/echo/ui/paging/ErrorPagingSource.kt

@@ -10,6 +10,8 @@ abstract class ErrorPagingSource<Key : Any, Value : Any> : PagingSource<Key, Val
         pagingSourceFactory = { this }
     ).flow
 
+    override val keyReuseSupported = true
+
     abstract val config: PagingConfig
 
     override suspend fun load(params: LoadParams<Key>): LoadResult<Key, Value> {

app/src/main/java/dev/brahmkshatriya/echo/ui/paging/PagedDataExt.kt

@@ -5,7 +5,7 @@ import dev.brahmkshatriya.echo.common.helpers.PagedData
 fun <T : Any> PagedData<T>.toFlow() = when (this) {
     is PagedData.Single -> SingleSource({ loadList() }, { clear() }).toFlow()
     is PagedData.Continuous ->
-        ContinuationSource<T, String>({ loadList(it) }, { invalidate(it) }).toFlow()
+        ContinuationSource({ loadList(it) }, { invalidate(it) }).toFlow()
     is PagedData.Concat ->
-        ContinuationSource<T, String>({ loadList(it) }, { invalidate(it) }).toFlow()
+        ContinuationSource({ loadList(it) }, { invalidate(it) }).toFlow()
 }

app/src/main/java/dev/brahmkshatriya/echo/utils/AnimationUtils.kt

@@ -3,19 +3,22 @@ package dev.brahmkshatriya.echo.utils
 import android.content.Context.MODE_PRIVATE
 import android.view.View
 import android.view.ViewPropertyAnimator
+import androidx.activity.BackEventCompat
+import androidx.activity.OnBackPressedCallback
+import androidx.core.view.animation.PathInterpolatorCompat
 import androidx.core.view.doOnPreDraw
 import androidx.core.view.forEach
 import androidx.core.view.forEachIndexed
 import androidx.core.view.isVisible
 import androidx.fragment.app.Fragment
 import androidx.interpolator.view.animation.FastOutSlowInInterpolator
-import com.google.android.material.R
 import com.google.android.material.color.MaterialColors
 import com.google.android.material.motion.MotionUtils
 import com.google.android.material.navigation.NavigationBarView
 import com.google.android.material.transition.MaterialArcMotion
 import com.google.android.material.transition.MaterialContainerTransform
 import com.google.android.material.transition.MaterialSharedAxis
+import dev.brahmkshatriya.echo.R
 import dev.brahmkshatriya.echo.ui.settings.LookFragment.Companion.ANIMATIONS_KEY
 import dev.brahmkshatriya.echo.ui.settings.LookFragment.Companion.SHARED_ELEMENT_KEY
 
@@ -24,7 +27,8 @@ fun startAnimation(
 ) = view.run {
     clearAnimation()
     val interpolator = MotionUtils.resolveThemeInterpolator(
-        context, R.attr.motionEasingStandardInterpolator, FastOutSlowInInterpolator()
+        context, com.google.android.material.R.attr.motionEasingStandardInterpolator,
+        FastOutSlowInInterpolator()
     )
     val duration = animationDuration * durationMultiplier
     animation.setInterpolator(interpolator).setDuration(duration.toLong()).start()
@@ -93,7 +97,7 @@ fun animateTranslation(view: View, old: Int, newHeight: Int) = view.run {
 private val View.animationDuration: Long
     get() = context.applicationContext.run {
         MotionUtils.resolveThemeDuration(
-            this, R.attr.motionDurationMedium1, 350
+            this, com.google.android.material.R.attr.motionDurationMedium1, 350
         ).toLong()
     }
 private val View.animations
@@ -106,10 +110,10 @@ private val View.sharedElementTransitions
         getSharedPreferences(packageName, MODE_PRIVATE).getBoolean(SHARED_ELEMENT_KEY, true)
     }
 
+private val GestureInterpolator = PathInterpolatorCompat.create(0f, 0f, 0f, 1f)
+
 fun Fragment.setupTransition(view: View) {
-    val color = MaterialColors.getColor(
-        view, dev.brahmkshatriya.echo.R.attr.echoBackground, 0
-    )
+    val color = MaterialColors.getColor(view, R.attr.echoBackground, 0)
     view.setBackgroundColor(color)
 
     if (view.animations) {
@@ -132,5 +136,45 @@ fun Fragment.setupTransition(view: View) {
 
         postponeEnterTransition()
         view.doOnPreDraw { startPostponedEnterTransition() }
+        if(parentFragmentManager.backStackEntryCount < 1) return
+        val predictiveBackMargin = resources.getDimensionPixelSize(R.dimen.predictive_back_margin)
+        var initialTouchY = -1f
+        requireActivity().onBackPressedDispatcher.addCallback(
+            viewLifecycleOwner,
+            object : OnBackPressedCallback(true) {
+                override fun handleOnBackPressed() {
+                    parentFragmentManager.popBackStack()
+                }
+
+                override fun handleOnBackProgressed(backEvent: BackEventCompat) {
+                    val progress = GestureInterpolator.getInterpolation(backEvent.progress)
+                    if(transitionName == null)
+                        view.alpha = 1 - progress
+                    if (initialTouchY < 0f)
+                        initialTouchY = backEvent.touchY
+                    val progressY = GestureInterpolator.getInterpolation(
+                        (backEvent.touchY - initialTouchY) / view.height
+                    )
+                    val maxTranslationX = (view.width / 20) - predictiveBackMargin
+                    view.translationX = progress * maxTranslationX *
+                            (if (backEvent.swipeEdge == BackEventCompat.EDGE_LEFT) -1 else 1)
+                    val maxTranslationY = (view.height / 20) - predictiveBackMargin
+                    view.translationY = progressY * maxTranslationY * -1
+                    val scale = 1f - (0.1f * progress)
+                    view.scaleX = scale
+                    view.scaleY = scale
+                }
+
+                override fun handleOnBackCancelled() {
+                    initialTouchY = -1f
+                    view.run {
+                        translationX = 0f
+                        translationY = 0f
+                        scaleX = 1f
+                        scaleY = 1f
+                    }
+                }
+            }
+        )
     }
 }

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

@@ -6,4 +6,5 @@
     <dimen name="nav_width">@dimen/collapsed_cover_size</dimen>
     <dimen name="nav_height">@dimen/collapsed_cover_size</dimen>
     <dimen name="player_info_peek_height">@dimen/nav_height</dimen>
+    <dimen name="predictive_back_margin">56dp</dimen>
 </resources>

common/src/main/java/dev/brahmkshatriya/echo/common/clients/SearchFeedClient.kt

@@ -17,7 +17,7 @@ interface SearchFeedClient {
     /**
      * Searches for quick search items.
      *
-     * @param query the query to search for.
+     * @param query the query to search for, will be empty if the user hasn't typed anything.
      * @return the quick search items.
      *
      * @see QuickSearchItem
@@ -34,7 +34,7 @@ interface SearchFeedClient {
     /**
      * Searches for tabs.
      *
-     * @param query the query to search for.
+     * @param query the query to search for, will be empty if the user hasn't typed anything.
      * @return the tabs.
      *
      * @see Tab
@@ -44,13 +44,13 @@ interface SearchFeedClient {
     /**
      * Searches for shelves.
      *
-     * @param query the query to search for.
+     * @param query the query to search for, will be empty if the user hasn't typed anything.
      * @param tab the tab to search in.
      * @return the paged shelves.
      *
      * @see Tab
      * @see Shelf
      * @see PagedData
      */
-    fun searchFeed(query: String?, tab: Tab?): PagedData<Shelf>
+    fun searchFeed(query: String, tab: Tab?): PagedData<Shelf>
 }