Remove divider above device switcher in panel

Remove the divider above the media device switcher Slice per the request.

Do a little refactor in Panel View, to use DividerItemDecoration instead of adding
divider views in layout file as the recycler view items divider.

Since dividers should be shown in most cases, we are setting DividerCondition to
DIVIDER_CONDITION_BOTH and default true to allow divider.  For the slice we don't
need divider (media device switch in this case) we are setting the the target
direction of isDividerAllowed (above in this case) to false.  Since we have
DIVIDER_CONDITION_BOTH, if one of the item view set the divider not allow, the
divider won't be shown.

Test: Visual/Manual inspection
Fixes: 126205139
Change-Id: Ic857705c90819ef9375f877a44bb32987b5d4438

src/com/android/settings/panel/PanelSlicesAdapter.java

@@ -16,6 +16,8 @@
 
 package com.android.settings.panel;
 
+import static com.android.settings.slices.CustomSliceRegistry.MEDIA_OUTPUT_INDICATOR_SLICE_URI;
+
 import android.app.settings.SettingsEnums;
 import android.content.Context;
 import android.net.Uri;
@@ -33,6 +35,7 @@ import androidx.slice.widget.SliceView;
 
 import com.android.settings.R;
 import com.android.settings.overlay.FeatureFactory;
+import com.google.android.setupdesign.DividerItemDecoration;
 
 import java.util.List;
 
@@ -80,10 +83,13 @@ public class PanelSlicesAdapter
     /**
      * ViewHolder for binding Slices to SliceViews.
      */
-    public static class SliceRowViewHolder extends RecyclerView.ViewHolder {
+    public static class SliceRowViewHolder extends RecyclerView.ViewHolder
+            implements DividerItemDecoration.DividedViewHolder {
 
         private final PanelContent mPanelContent;
 
+        private boolean mDividerAllowedAbove = true;
+
         @VisibleForTesting
         LiveData<Slice> sliceLiveData;
 
@@ -103,6 +109,11 @@ public class PanelSlicesAdapter
             sliceLiveData = SliceLiveData.fromUri(context, sliceUri);
             sliceLiveData.observe(fragment.getViewLifecycleOwner(), sliceView);
 
+            // Do not show the divider above media devices switcher slice per request
+            if (sliceUri.equals(MEDIA_OUTPUT_INDICATOR_SLICE_URI)) {
+                mDividerAllowedAbove = false;
+            }
+
             // Log Panel interaction
             sliceView.setOnSliceActionListener(
                     ((eventInfo, sliceItem) -> {
@@ -116,5 +127,15 @@ public class PanelSlicesAdapter
                     })
             );
         }
+
+        @Override
+        public boolean isDividerAllowedAbove() {
+            return mDividerAllowedAbove;
+        }
+
+        @Override
+        public boolean isDividerAllowedBelow() {
+            return true;
+        }
     }
 }