playback: improve compact -> full transition

Improve the way the compact playback view transforms into the full
playback view by splitting their view animations in two. This makes
the transition more akin to the Android 12 notification menu, which
due to the nature of how I'm fading views really does make it more
user friendly. Also re-add the "Now Playing" title and a new subtitle
displaying the currently playing artist.

app/src/main/java/org/oxycblt/auxio/playback/PlaybackFragment.kt

@@ -109,6 +109,14 @@ class PlaybackFragment : Fragment() {
             }
         }
 
+        playbackModel.parent.observe(viewLifecycleOwner) { parent ->
+            if (parent != null) {
+                binding.playbackToolbar.subtitle = parent.resolvedName
+            } else {
+                binding.playbackToolbar.setSubtitle(R.string.lbl_all_songs)
+            }
+        }
+
         playbackModel.isShuffling.observe(viewLifecycleOwner) { isShuffling ->
             binding.playbackShuffle.isActivated = isShuffling
         }

app/src/main/java/org/oxycblt/auxio/playback/PlaybackLayout.kt

@@ -527,24 +527,28 @@ class PlaybackLayout @JvmOverloads constructor(
     }
 
     /**
-     * Update the view transitions done when the panel slides up.
+     * Do the nice view animations that occur whenever we slide up the playback panel.
+     * The way I transition is largely inspired by Android 12's notification panel, with the
+     * compact view fading out completely before the panel view fades in. We don't fade out the
+     * content though so we have cohesion between the other sliding transitions.
      */
     private fun updatePanelTransition() {
-        val outAlpha = min(1 - panelOffset, 1f)
+        val ratio = max(panelOffset, 0f)
-        val inAlpha = max(panelOffset, 0f)
 
-        contentView.apply {
+        val outRatio = 1 - ratio
-            alpha = outAlpha
+        val halfOutRatio = min(ratio / 0.5f, 1f)
-            isInvisible = alpha == 0f
+        val halfInRatio = max(ratio - 0.5f, 0f) / 0.5f
-        }
+
+        // Optimize out drawing for this view completely
+        contentView.isInvisible = outRatio == 0f
 
         // Slowly reduce the elevation as we slide up, eventually resulting in a neutral color
         // instead of an elevated one when fully expanded.
-        (playbackContainerView.background as MaterialShapeDrawable).alpha = (outAlpha * 255).toInt()
+        (playbackContainerView.background as MaterialShapeDrawable).alpha = (outRatio * 255).toInt()
 
         // Fade out our bar view as we slide up
         playbackBarView.apply {
-            alpha = outAlpha
+            alpha = min(1 - halfOutRatio, 1f)
             isInvisible = alpha == 0f
 
             // When edge-to-edge is enabled, the playback bar will not fade out into the
@@ -561,7 +565,7 @@ class PlaybackLayout @JvmOverloads constructor(
 
                 params.setMargins(
                     params.leftMargin,
-                    (bars.top * max(panelOffset, 0f)).toInt(),
+                    (bars.top * halfOutRatio).toInt(),
                     params.rightMargin,
                     params.bottomMargin
                 )
@@ -575,7 +579,7 @@ class PlaybackLayout @JvmOverloads constructor(
 
         // Fade in our panel as we slide up
         playbackPanelView.apply {
-            alpha = inAlpha
+            alpha = halfInRatio
             isInvisible = alpha == 0f
         }
     }
@@ -587,10 +591,11 @@ class PlaybackLayout @JvmOverloads constructor(
         (computePanelTopPosition(0f) - topPosition).toFloat() / panelRange
 
     private fun smoothSlideTo(offset: Float) {
-        // Find the new top position and animate the panel to that
+        val okay = dragHelper.smoothSlideViewTo(
-        val panelTop = computePanelTopPosition(offset)
+            playbackContainerView, playbackContainerView.left, computePanelTopPosition(offset)
+        )
 
-        if (dragHelper.smoothSlideViewTo(playbackContainerView, playbackContainerView.left, panelTop)) {
+        if (okay) {
             postInvalidateOnAnimation()
         }
     }

app/src/main/res/layout-land/fragment_playback.xml

@@ -26,11 +26,12 @@
         android:layout_height="match_parent"
         android:clipToPadding="false">
 
-        <androidx.appcompat.widget.Toolbar
+        <com.google.android.material.appbar.MaterialToolbar
             android:id="@+id/playback_toolbar"
             style="@style/Widget.Auxio.Toolbar.Icon.Down"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toTopOf="parent"
+            app:title="@string/info_widget_name"
             app:menu="@menu/menu_playback" />
 
         <ImageView

app/src/main/res/layout-sw600dp-land/fragment_playback.xml

@@ -26,10 +26,11 @@
         android:layout_height="match_parent"
         android:clipToPadding="false">
 
-        <androidx.appcompat.widget.Toolbar
+        <com.google.android.material.appbar.MaterialToolbar
             android:id="@+id/playback_toolbar"
             style="@style/Widget.Auxio.Toolbar.Icon.Down"
             app:layout_constraintStart_toStartOf="parent"
+            app:title="@string/info_widget_name"
             app:layout_constraintTop_toTopOf="parent"
             app:menu="@menu/menu_playback" />
 

app/src/main/res/layout-sw600dp/fragment_playback.xml

@@ -26,11 +26,12 @@
         android:layout_height="match_parent"
         android:clipToPadding="false">
 
-        <androidx.appcompat.widget.Toolbar
+        <com.google.android.material.appbar.MaterialToolbar
             android:id="@+id/playback_toolbar"
             style="@style/Widget.Auxio.Toolbar.Icon.Down"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toTopOf="parent"
+            app:title="@string/info_widget_name"
             app:menu="@menu/menu_playback" />
 
         <ImageView

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

@@ -25,11 +25,12 @@
         android:layout_height="match_parent"
         android:clipToPadding="false">
 
-        <androidx.appcompat.widget.Toolbar
+        <com.google.android.material.appbar.MaterialToolbar
             android:id="@+id/playback_toolbar"
             style="@style/Widget.Auxio.Toolbar.Icon.Down"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toTopOf="parent"
+            app:title="@string/info_widget_name"
             app:menu="@menu/menu_playback" />
 
         <ImageView