home: expand appbar when selection starts

Expand the home AppBarLayout when a selection begins (Excluding
initialization)

app/src/main/java/org/oxycblt/auxio/detail/AlbumDetailFragment.kt

@@ -96,7 +96,11 @@ class AlbumDetailFragment :
 
     override fun onDestroyBinding(binding: FragmentDetailBinding) {
         super.onDestroyBinding(binding)
-        binding.detailToolbar.setOnMenuItemClickListener(null)
+        binding.detailToolbar.apply {
+            setNavigationOnClickListener(null)
+            setOnMenuItemClickListener(null)
+        }
+
         binding.detailRecycler.adapter = null
     }
 

app/src/main/java/org/oxycblt/auxio/detail/ArtistDetailFragment.kt

@@ -91,7 +91,11 @@ class ArtistDetailFragment :
 
     override fun onDestroyBinding(binding: FragmentDetailBinding) {
         super.onDestroyBinding(binding)
-        binding.detailToolbar.setOnMenuItemClickListener(null)
+        binding.detailToolbar.apply {
+            setNavigationOnClickListener(null)
+            setOnMenuItemClickListener(null)
+        }
+
         binding.detailRecycler.adapter = null
     }
 

app/src/main/java/org/oxycblt/auxio/detail/GenreDetailFragment.kt

@@ -92,7 +92,11 @@ class GenreDetailFragment :
 
     override fun onDestroyBinding(binding: FragmentDetailBinding) {
         super.onDestroyBinding(binding)
-        binding.detailToolbar.setOnMenuItemClickListener(null)
+        binding.detailToolbar.apply {
+            setNavigationOnClickListener(null)
+            setOnMenuItemClickListener(null)
+        }
+
         binding.detailRecycler.adapter = null
     }
 

app/src/main/java/org/oxycblt/auxio/home/HomeFragment.kt

@@ -29,6 +29,7 @@ import androidx.core.view.iterator
 import androidx.core.view.updatePadding
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.activityViewModels
+import androidx.fragment.app.viewModels
 import androidx.navigation.fragment.findNavController
 import androidx.recyclerview.widget.RecyclerView
 import androidx.viewpager2.adapter.FragmentStateAdapter
@@ -58,7 +59,7 @@ import org.oxycblt.auxio.music.system.Indexer
 import org.oxycblt.auxio.playback.PlaybackViewModel
 import org.oxycblt.auxio.ui.MainNavigationAction
 import org.oxycblt.auxio.ui.NavigationViewModel
-import org.oxycblt.auxio.ui.SelectionViewModel
+import org.oxycblt.auxio.ui.selection.SelectionViewModel
 import org.oxycblt.auxio.ui.fragment.ViewBindingFragment
 import org.oxycblt.auxio.util.*
 
@@ -69,10 +70,11 @@ import org.oxycblt.auxio.util.*
  */
 class HomeFragment : ViewBindingFragment<FragmentHomeBinding>(), Toolbar.OnMenuItemClickListener {
     private val playbackModel: PlaybackViewModel by androidActivityViewModels()
-    private val navModel: NavigationViewModel by activityViewModels()
     private val homeModel: HomeViewModel by androidActivityViewModels()
-    private val selectionModel: SelectionViewModel by activityViewModels()
     private val musicModel: MusicViewModel by activityViewModels()
+    private val navModel: NavigationViewModel by activityViewModels()
+    // Makes no sense to share selections across screens
+    private val selectionModel: SelectionViewModel by activityViewModels()
 
     // lifecycleObject builds this in the creation step, so doing this is okay.
     private val storagePermissionLauncher: ActivityResultLauncher<String> by lifecycleObject {
@@ -237,15 +239,12 @@ class HomeFragment : ViewBindingFragment<FragmentHomeBinding>(), Toolbar.OnMenuI
     private fun updateCurrentTab(tab: MusicMode) {
         // Make sure that we update the scrolling view and allowed menu items whenever
         // the tab changes.
-        val binding = requireBinding()
         when (tab) {
             MusicMode.SONGS -> {
                 updateSortMenu(tab) { id -> id != R.id.option_sort_count }
-                binding.homeAppbar.liftOnScrollTargetViewId = R.id.home_song_list
             }
             MusicMode.ALBUMS -> {
                 updateSortMenu(tab) { id -> id != R.id.option_sort_album }
-                binding.homeAppbar.liftOnScrollTargetViewId = R.id.home_album_list
             }
             MusicMode.ARTISTS -> {
                 updateSortMenu(tab) { id ->
@@ -254,7 +253,6 @@ class HomeFragment : ViewBindingFragment<FragmentHomeBinding>(), Toolbar.OnMenuI
                         id == R.id.option_sort_count ||
                         id == R.id.option_sort_duration
                 }
-                binding.homeAppbar.liftOnScrollTargetViewId = R.id.home_artist_list
             }
             MusicMode.GENRES -> {
                 updateSortMenu(tab) { id ->
@@ -263,9 +261,10 @@ class HomeFragment : ViewBindingFragment<FragmentHomeBinding>(), Toolbar.OnMenuI
                         id == R.id.option_sort_count ||
                         id == R.id.option_sort_duration
                 }
-                binding.homeAppbar.liftOnScrollTargetViewId = R.id.home_genre_list
             }
         }
+
+        requireBinding().homeAppbar.liftOnScrollTargetViewId = getRecyclerId(tab)
     }
 
     private fun updateSortMenu(mode: MusicMode, isVisible: (Int) -> Boolean) {
@@ -402,7 +401,15 @@ class HomeFragment : ViewBindingFragment<FragmentHomeBinding>(), Toolbar.OnMenuI
     }
 
     private fun updateSelection(selected: List<Music>) {
-        requireBinding().homeToolbarOverlay.updateSelectionAmount(selected.size)
+        val binding = requireBinding()
+        if (binding.homeToolbarOverlay.updateSelectionAmount(selected.size) && selected.isNotEmpty()) {
+            logD("Significant selection occurred, expanding AppBar")
+            // Significant enough change where we want to expand the RecyclerView
+            binding.homeAppbar.expandWithRecycler(
+                binding.homePager.findViewById(
+                    getRecyclerId(homeModel.currentTab.value))
+            )
+        }
     }
 
     private fun handleNavigation(item: Music?) {
@@ -449,6 +456,14 @@ class HomeFragment : ViewBindingFragment<FragmentHomeBinding>(), Toolbar.OnMenuI
         adapter = HomePagerAdapter()
     }
 
+    private fun getRecyclerId(tab: MusicMode) =
+        when (tab) {
+            MusicMode.SONGS -> R.id.home_song_recycler
+            MusicMode.ALBUMS -> R.id.home_album_recycler
+            MusicMode.ARTISTS -> R.id.home_artist_recycler
+            MusicMode.GENRES -> R.id.home_genre_recycler
+        }
+
     private inner class HomePagerAdapter :
         FragmentStateAdapter(childFragmentManager, viewLifecycleOwner.lifecycle) {
 

app/src/main/java/org/oxycblt/auxio/home/list/AlbumListFragment.kt

@@ -51,7 +51,7 @@ class AlbumListFragment : HomeListFragment<Album>() {
         super.onBindingCreated(binding, savedInstanceState)
 
         binding.homeRecycler.apply {
-            id = R.id.home_album_list
+            id = R.id.home_album_recycler
             adapter = homeAdapter
         }
 

app/src/main/java/org/oxycblt/auxio/home/list/ArtistListFragment.kt

@@ -47,7 +47,7 @@ class ArtistListFragment : HomeListFragment<Artist>() {
         super.onBindingCreated(binding, savedInstanceState)
 
         binding.homeRecycler.apply {
-            id = R.id.home_artist_list
+            id = R.id.home_artist_recycler
             adapter = homeAdapter
         }
 

app/src/main/java/org/oxycblt/auxio/home/list/GenreListFragment.kt

@@ -46,7 +46,7 @@ class GenreListFragment : HomeListFragment<Genre>() {
         super.onBindingCreated(binding, savedInstanceState)
 
         binding.homeRecycler.apply {
-            id = R.id.home_genre_list
+            id = R.id.home_genre_recycler
             adapter = homeAdapter
         }
 

app/src/main/java/org/oxycblt/auxio/home/list/HomeListFragment.kt

@@ -24,7 +24,7 @@ import androidx.fragment.app.activityViewModels
 import org.oxycblt.auxio.databinding.FragmentHomeListBinding
 import org.oxycblt.auxio.home.HomeViewModel
 import org.oxycblt.auxio.music.Music
-import org.oxycblt.auxio.ui.SelectionViewModel
+import org.oxycblt.auxio.ui.selection.SelectionViewModel
 import org.oxycblt.auxio.ui.fastscroll.FastScrollRecyclerView
 import org.oxycblt.auxio.ui.fragment.MenuFragment
 import org.oxycblt.auxio.ui.recycler.Item

app/src/main/java/org/oxycblt/auxio/home/list/SongListFragment.kt

@@ -54,7 +54,7 @@ class SongListFragment : HomeListFragment<Song>() {
         super.onBindingCreated(binding, savedInstanceState)
 
         binding.homeRecycler.apply {
-            id = R.id.home_song_list
+            id = R.id.home_song_recycler
             adapter = homeAdapter
         }
 

app/src/main/java/org/oxycblt/auxio/playback/state/PlaybackStateManager.kt

@@ -65,6 +65,9 @@ class PlaybackStateManager private constructor() {
         private set
     private var _queue = mutableListOf<Song>()
 
+    private val orderedQueue = listOf<Song>()
+    private val shuffledQueue = listOf<Song>()
+
     /** The current queue determined by [parent] */
     val queue
         get() = _queue

app/src/main/java/org/oxycblt/auxio/ui/AuxioAppBarLayout.kt

@@ -22,15 +22,18 @@ import android.util.AttributeSet
 import android.view.View
 import android.view.ViewGroup
 import android.view.ViewTreeObserver
+import android.view.animation.AnimationUtils
 import androidx.annotation.AttrRes
 import androidx.coordinatorlayout.widget.CoordinatorLayout
 import androidx.core.content.res.ResourcesCompat
+import androidx.recyclerview.widget.RecyclerView
 import com.google.android.material.appbar.AppBarLayout
 import org.oxycblt.auxio.util.coordinatorLayoutBehavior
+import org.oxycblt.auxio.util.logD
 
 /**
- * An [AppBarLayout] that fixes a bug with the default implementation where the lifted state will
+ * An [AppBarLayout] that fixes several bugs with the default implementation where the lifted
- * not properly respond to RecyclerView events.
+ * state will not properly respond to RecyclerView events.
  *
  * **Note:** This layout relies on [AppBarLayout.liftOnScrollTargetViewId] to figure out what
  * scrolling view to use. Failure to specify this will result in the layout not working.
@@ -60,6 +63,17 @@ constructor(context: Context, attrs: AttributeSet? = null, @AttrRes defStyleAttr
         viewTreeObserver.addOnPreDrawListener(onPreDraw)
     }
 
+    /**
+     * Expand this app bar layout with the given recyclerview, preventing it from
+     * jumping around.
+     */
+    fun expandWithRecycler(recycler: RecyclerView?) {
+        setExpanded(true)
+        recycler?.let {
+            addOnOffsetChangedListener(ExpansionHackListener(it))
+        }
+    }
+
     override fun onDetachedFromWindow() {
         super.onDetachedFromWindow()
         viewTreeObserver.removeOnPreDrawListener(onPreDraw)
@@ -88,4 +102,30 @@ constructor(context: Context, attrs: AttributeSet? = null, @AttrRes defStyleAttr
 
         return scrollingChild
     }
+
+    /**
+     * Hack to prevent RecyclerView jumping when the appbar expands.
+     * Adapted from Material Files:
+     * https://github.com/zhanghai/MaterialFiles/blob/master/app/src/main/java/me/zhanghai/android/files/ui/AppBarLayoutExpandHackListener.kt
+     */
+    private class ExpansionHackListener(private val recycler: RecyclerView) : OnOffsetChangedListener {
+        private val offsetAnimationMaxEndTime = (AnimationUtils.currentAnimationTimeMillis()
+            + 600)
+
+        private var lastVerticalOffset: Int? = null
+
+        override fun onOffsetChanged(appBarLayout: AppBarLayout, verticalOffset: Int) {
+            if (verticalOffset == 0
+                || AnimationUtils.currentAnimationTimeMillis() > offsetAnimationMaxEndTime) {
+                // AppBarLayout crashes with IndexOutOfBoundsException when a non-last listener removes
+                // itself, so we have to do the removal asynchronously.
+                appBarLayout.postOnAnimation { appBarLayout.removeOnOffsetChangedListener(this) }
+            }
+            val lastVerticalOffset = lastVerticalOffset
+            this.lastVerticalOffset = verticalOffset
+            if (lastVerticalOffset != null) {
+                recycler.scrollBy(0, verticalOffset - lastVerticalOffset)
+            }
+        }
+    }
 }

app/src/main/java/org/oxycblt/auxio/ui/fastscroll/FastScrollRecyclerView.kt

@@ -463,7 +463,6 @@ constructor(context: Context, attrs: AttributeSet? = null, @AttrRes defStyleAttr
     }
 
     private fun animateViewIn(view: View) {
-        logD(view.translationX)
         view
             .animate()
             .alpha(1f)

app/src/main/java/org/oxycblt/auxio/ui/selection/SelectionToolbarOverlay.kt

@@ -1,20 +1,15 @@
-package org.oxycblt.auxio.ui
+package org.oxycblt.auxio.ui.selection
 
 import android.animation.ValueAnimator
 import android.content.Context
 import android.util.AttributeSet
-import android.view.View
 import android.widget.FrameLayout
 import androidx.annotation.AttrRes
 import androidx.appcompat.widget.Toolbar
 import androidx.core.view.isInvisible
-import androidx.transition.TransitionManager
 import com.google.android.material.appbar.MaterialToolbar
-import com.google.android.material.transition.MaterialFadeThrough
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.util.logD
-import kotlin.math.max
-import kotlin.math.min
 
 /**
  * A wrapper around a Toolbar that enables an overlaid toolbar showing information about
@@ -31,8 +26,6 @@ constructor(context: Context, attrs: AttributeSet? = null, @AttrRes defStyleAttr
         setNavigationIcon(R.drawable.ic_close_24)
     }
 
-    private val selectionMenu = selectionToolbar.menu
-
     private var fadeThroughAnimator: ValueAnimator? = null
 
     override fun onFinishInflate() {
@@ -103,8 +96,10 @@ constructor(context: Context, attrs: AttributeSet? = null, @AttrRes defStyleAttr
         }
 
         if (!isLaidOut) {
+            // Not laid out, just change it immediately while are not shown to the user.
+            // This is an initialization, so we return false despite changing.
             changeToolbarAlpha(targetInnerAlpha)
-            return true
+            return false
         }
 
         if (fadeThroughAnimator != null) {

app/src/main/java/org/oxycblt/auxio/ui/selection/SelectionViewModel.kt

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.ui
+package org.oxycblt.auxio.ui.selection
 
 import androidx.lifecycle.ViewModel
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -23,6 +23,10 @@ import kotlinx.coroutines.flow.StateFlow
 import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.util.logD
 
+/**
+ * ViewModel that manages the current selection.
+ * @author OxygenCobalt
+ */
 class SelectionViewModel : ViewModel() {
     private val _selected = MutableStateFlow(listOf<Music>())
     val selected: StateFlow<List<Music>>
@@ -47,4 +51,9 @@ class SelectionViewModel : ViewModel() {
             _selected.value = listOf()
         }
     }
+
+    override fun onCleared() {
+        super.onCleared()
+        logD("Cleared")
+    }
 }

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

@@ -13,7 +13,7 @@
         style="@style/Widget.Auxio.AppBarLayout"
         android:fitsSystemWindows="true">
 
-        <org.oxycblt.auxio.ui.SelectionToolbarOverlay
+        <org.oxycblt.auxio.ui.selection.SelectionToolbarOverlay
             android:id="@+id/home_toolbar_overlay"
             android:layout_width="match_parent"
             android:layout_height="wrap_content">
@@ -26,7 +26,7 @@
                 app:menu="@menu/menu_home"
                 app:title="@string/info_app_name" />
 
-        </org.oxycblt.auxio.ui.SelectionToolbarOverlay>
+        </org.oxycblt.auxio.ui.selection.SelectionToolbarOverlay>
 
         <com.google.android.material.tabs.TabLayout
             android:id="@+id/home_tabs"

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

@@ -4,10 +4,11 @@
     <item
         android:id="@+id/action_play_next_selection"
         android:title="@string/lbl_play_next"
-        android:icon="@drawable/ic_play_next_24"
+        android:icon="@drawable/ic_play_next"
         app:showAsAction="ifRoom"/>
     <item
         android:id="@+id/action_queue_add_selection"
+        android:icon="@drawable/ic_play_next"
         android:title="@string/lbl_queue_add"
         app:showAsAction="never" />
     <!-- TOOD: Disabled until able to get queue system into shape -->

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

@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <!-- This is for HomeFragment's AppBarLayout. Explanations for these can be found there. -->
-    <item name="home_song_list" type="id" />
+    <item name="home_song_recycler" type="id" />
-    <item name="home_album_list" type="id" />
+    <item name="home_album_recycler" type="id" />
-    <item name="home_artist_list" type="id" />
+    <item name="home_artist_recycler" type="id" />
-    <item name="home_genre_list" type="id" />
+    <item name="home_genre_recycler" type="id" />
 
     <integer name="anim_fade_enter_duration">200</integer>
     <integer name="anim_fade_exit_duration">100</integer>