style: enable drop shadows before api 28

Re-enable drop shadows on the playback bar and queue items on API 27
and lower. This is mostly to make Auxio line up with the M3 styles as
a whole.

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## dev [v2.2.2 or 2.3.0]
 
+#### Dev/Meta
+- Enabled elevation drop shadows below Android P for consistency
+
 ## v2.2.1
 #### What's Improved
 - Updated chinese translations [courtesy of cccClyde]

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

@@ -23,9 +23,11 @@ import org.oxycblt.auxio.BuildConfig
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.detail.DetailViewModel
 import org.oxycblt.auxio.music.Song
+import org.oxycblt.auxio.util.disableDropShadowCompat
 import org.oxycblt.auxio.util.getAttrColorSafe
-import org.oxycblt.auxio.util.getDimenSizeSafe
+import org.oxycblt.auxio.util.getDimenSafe
 import org.oxycblt.auxio.util.getDrawableSafe
+import org.oxycblt.auxio.util.pxOfDp
 import org.oxycblt.auxio.util.replaceSystemBarInsetsCompat
 import org.oxycblt.auxio.util.stateList
 import org.oxycblt.auxio.util.systemBarInsetsCompat
@@ -98,6 +100,8 @@ class PlaybackLayout @JvmOverloads constructor(
     private var initMotionY = 0f
     private val tRect = Rect()
 
+    private val elevationNormal = context.getDimenSafe(R.dimen.elevation_normal)
+
     /** See [isDragging] */
     private val dragStateField = ViewDragHelper::class.java.getDeclaredField("mDragState").apply {
         isAccessible = true
@@ -117,7 +121,7 @@ class PlaybackLayout @JvmOverloads constructor(
 
             playbackContainerBg = MaterialShapeDrawable.createWithElevationOverlay(context).apply {
                 fillColor = context.getAttrColorSafe(R.attr.colorSurface).stateList
-                elevation = context.getDimenSizeSafe(R.dimen.elevation_normal).toFloat()
+                elevation = context.pxOfDp(elevationNormal).toFloat()
             }
 
             // The way we fade out the elevation overlay is not by actually reducing the elevation
@@ -127,6 +131,8 @@ class PlaybackLayout @JvmOverloads constructor(
             background = (context.getDrawableSafe(R.drawable.ui_panel_bg) as LayerDrawable).apply {
                 setDrawableByLayerId(R.id.panel_overlay, playbackContainerBg)
             }
+
+            disableDropShadowCompat()
         }
 
         playbackBarView = PlaybackBarView(context).apply {
@@ -535,6 +541,7 @@ class PlaybackLayout @JvmOverloads constructor(
         // Slowly reduce the elevation of the container as we slide up, eventually resulting in a
         // neutral color instead of an elevated one when fully expanded.
         playbackContainerBg.alpha = (outRatio * 255).toInt()
+        playbackContainerView.translationZ = elevationNormal * outRatio
 
         // Fade out our bar view as we slide up
         playbackBarView.apply {

app/src/main/java/org/oxycblt/auxio/playback/queue/QueueAdapter.kt

@@ -37,6 +37,7 @@ import org.oxycblt.auxio.ui.ActionHeaderViewHolder
 import org.oxycblt.auxio.ui.BaseViewHolder
 import org.oxycblt.auxio.ui.DiffCallback
 import org.oxycblt.auxio.ui.HeaderViewHolder
+import org.oxycblt.auxio.util.disableDropShadowCompat
 import org.oxycblt.auxio.util.inflater
 import org.oxycblt.auxio.util.logE
 import org.oxycblt.auxio.util.stateList
@@ -132,6 +133,8 @@ class QueueAdapter(
             ).apply {
                 fillColor = (binding.body.background as ColorDrawable).color.stateList
             }
+
+            binding.root.disableDropShadowCompat()
         }
 
         @SuppressLint("ClickableViewAccessibility")

app/src/main/java/org/oxycblt/auxio/playback/queue/QueueDragCallback.kt

@@ -86,7 +86,6 @@ class QueueDragCallback(private val playbackModel: PlaybackViewModel) : ItemTouc
         // themselves when being dragged. Too bad google's implementation of this doesn't even
         // work! To emulate it on my own, I check if this child is in a drag state and then animate
         // an elevation change.
-
         val holder = viewHolder as QueueAdapter.QueueSongViewHolder
 
         if (shouldLift && isCurrentlyActive && actionState == ItemTouchHelper.ACTION_STATE_DRAG) {

app/src/main/java/org/oxycblt/auxio/util/ViewUtil.kt

@@ -22,6 +22,7 @@ import android.content.res.ColorStateList
 import android.graphics.Insets
 import android.graphics.Rect
 import android.os.Build
+import android.view.View
 import android.view.WindowInsets
 import androidx.annotation.ColorRes
 import androidx.recyclerview.widget.GridLayoutManager
@@ -62,6 +63,18 @@ fun RecyclerView.applySpans(shouldBeFullWidth: ((Int) -> Boolean)? = null) {
  */
 fun RecyclerView.canScroll(): Boolean = computeVerticalScrollRange() > height
 
+/**
+ * Disables drop shadows on a view programmatically in a version-compatible manner.
+ * This only works on Android 9 and above. Below that version, shadows will remain visible.
+ */
+fun View.disableDropShadowCompat() {
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
+        val transparent = context.getColorSafe(android.R.color.transparent)
+        outlineAmbientShadowColor = transparent
+        outlineSpotShadowColor = transparent
+    }
+}
+
 /**
  * Resolve system bar insets in a version-aware manner. This can be used to apply padding to
  * a view that properly follows all the frustrating changes that were made between 8-11.