Fix A11y tools focus on blocked component 2/2

 - Add a callback to BottomActionBar, let the registrant receive BottomActionBar's state and disable the a11y param when expended
 video: https://drive.google.com/file/d/1T1w1bnAoQYvgpdSa7eYsFPOspjWV4hEP/view?usp=sharing

 Bug: 157871987
 Test: manually

Change-Id: I59666dde616c86d176d10bee0d1081358bb18959
diff --git a/src/com/android/wallpaper/picker/ImagePreviewFragment.java b/src/com/android/wallpaper/picker/ImagePreviewFragment.java
index 566cbaa..84bc95b 100755
--- a/src/com/android/wallpaper/picker/ImagePreviewFragment.java
+++ b/src/com/android/wallpaper/picker/ImagePreviewFragment.java
@@ -59,6 +59,7 @@
 import com.android.wallpaper.util.SizeCalculator;
 import com.android.wallpaper.util.WallpaperCropUtils;
 import com.android.wallpaper.widget.BottomActionBar;
+import com.android.wallpaper.widget.BottomActionBar.AccessibilityCallback;
 import com.android.wallpaper.widget.LockScreenOverlayUpdater;
 import com.android.wallpaper.widget.WallpaperColorsLoader;
 import com.android.wallpaper.widget.WallpaperInfoView;
@@ -244,6 +245,22 @@
         );
         mBottomActionBar.setActionSelectedListener(EDIT, this::setEditingEnabled);
         mBottomActionBar.setActionClickListener(APPLY, this::onSetWallpaperClicked);
+
+        // Update target view's accessibility param since it will be blocked by the bottom sheet
+        // when expanded.
+        mBottomActionBar.setAccessibilityCallback(new AccessibilityCallback() {
+            @Override
+            public void onBottomSheetCollapsed() {
+                mTabs.setImportantForAccessibility(View.IMPORTANT_FOR_ACCESSIBILITY_YES);
+            }
+
+            @Override
+            public void onBottomSheetExpanded() {
+                mTabs.setImportantForAccessibility(
+                        View.IMPORTANT_FOR_ACCESSIBILITY_NO_HIDE_DESCENDANTS);
+            }
+        });
+
         // Will trigger onActionSelected callback to update the editing state.
         mBottomActionBar.setDefaultSelectedButton(EDIT);
         mBottomActionBar.show();