Change unfold background color based on split screen state

After this cl, task background will have the same color of the split
divider when the fold/unfold animation happens while in splitscreen.

For all other cases, the behaviour is the same as before.

Before this cl, the task background and split divider had different
colors that didn't match.

Bug: 278071265
Test: 1. Folded while in split screen
2. checked the colors match
3. went to single app
4. checked the color was the original one

Change-Id: I6915ea0c249a2c1de15f59ed01f8290e0b8b02b8

libs/WindowManager/Shell/src/com/android/wm/shell/unfold/UnfoldBackgroundController.java

@@ -20,6 +20,7 @@ import static android.graphics.Color.blue;
 import static android.graphics.Color.green;
 import static android.graphics.Color.red;
 
+import android.annotation.ColorRes;
 import android.annotation.NonNull;
 import android.content.Context;
 import android.view.SurfaceControl;
@@ -33,10 +34,14 @@ public class UnfoldBackgroundController {
 
     private static final int BACKGROUND_LAYER_Z_INDEX = -1;
     private final float[] mBackgroundColor;
+    private final float[] mSplitScreenBackgroundColor;
+    private float[] mBackgroundColorSet;
     private SurfaceControl mBackgroundLayer;
+    private boolean mSplitScreenVisible = false;
 
     public UnfoldBackgroundController(@NonNull Context context) {
-        mBackgroundColor = getBackgroundColor(context);
+        mBackgroundColor = getRGBColorFromId(context, R.color.unfold_background);
+        mSplitScreenBackgroundColor = getRGBColorFromId(context, R.color.split_divider_background);
     }
 
     /**
@@ -44,7 +49,14 @@ public class UnfoldBackgroundController {
      * @param transaction where we should add the background if it is not added
      */
     public void ensureBackground(@NonNull SurfaceControl.Transaction transaction) {
-        if (mBackgroundLayer != null) return;
+        float[] expectedColor = getCurrentBackgroundColor();
+        if (mBackgroundLayer != null) {
+            if (mBackgroundColorSet != expectedColor) {
+                transaction.setColor(mBackgroundLayer, expectedColor);
+                mBackgroundColorSet = expectedColor;
+            }
+            return;
+        }
 
         SurfaceControl.Builder colorLayerBuilder = new SurfaceControl.Builder()
                 .setName("app-unfold-background")
@@ -53,9 +65,10 @@ public class UnfoldBackgroundController {
         mBackgroundLayer = colorLayerBuilder.build();
 
         transaction
-                .setColor(mBackgroundLayer, mBackgroundColor)
+                .setColor(mBackgroundLayer, expectedColor)
                 .show(mBackgroundLayer)
                 .setLayer(mBackgroundLayer, BACKGROUND_LAYER_Z_INDEX);
+        mBackgroundColorSet = expectedColor;
     }
 
     /**
@@ -70,8 +83,25 @@ public class UnfoldBackgroundController {
         mBackgroundLayer = null;
     }
 
-    private float[] getBackgroundColor(Context context) {
-        int colorInt = context.getResources().getColor(R.color.unfold_background);
+    /**
+     * Expected to be called whenever split screen visibility changes.
+     *
+     * @param visible True when split screen is visible
+     */
+    public void onSplitVisibilityChanged(boolean visible) {
+        mSplitScreenVisible = visible;
+    }
+
+    private float[] getCurrentBackgroundColor() {
+        if (mSplitScreenVisible) {
+            return mSplitScreenBackgroundColor;
+        } else {
+            return mBackgroundColor;
+        }
+    }
+
+    private float[] getRGBColorFromId(Context context, @ColorRes int id) {
+        int colorInt = context.getResources().getColor(id);
         return new float[]{
                 (float) red(colorInt) / 255.0F,
                 (float) green(colorInt) / 255.0F,

libs/WindowManager/Shell/src/com/android/wm/shell/unfold/animation/SplitTaskUnfoldAnimator.java

@@ -292,6 +292,11 @@ public class SplitTaskUnfoldAnimator implements UnfoldTaskAnimator,
                 .setCornerRadius(context.mLeash, 0.0F);
     }
 
+    @Override
+    public void onSplitVisibilityChanged(boolean visible) {
+        mUnfoldBackgroundController.onSplitVisibilityChanged(visible);
+    }
+
     private class AnimationContext {
         final SurfaceControl mLeash;