Fixes inset padding in android accessibility bridge (flutter#27083)

Author: chunhtai

ci/licenses_golden/licenses_flutter

@@ -898,6 +898,7 @@ FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/platform/Virtual
 FILE: ../../../flutter/shell/platform/android/io/flutter/util/PathUtils.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/util/Preconditions.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/util/Predicate.java
+FILE: ../../../flutter/shell/platform/android/io/flutter/util/ViewUtils.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/view/AccessibilityBridge.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/view/AccessibilityViewEmbedder.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/view/FlutterCallbackInformation.java

shell/platform/android/BUILD.gn

@@ -241,6 +241,7 @@ android_java_sources = [
   "io/flutter/util/PathUtils.java",
   "io/flutter/util/Preconditions.java",
   "io/flutter/util/Predicate.java",
+  "io/flutter/util/ViewUtils.java",
   "io/flutter/view/AccessibilityBridge.java",
   "io/flutter/view/AccessibilityViewEmbedder.java",
   "io/flutter/view/FlutterCallbackInformation.java",
@@ -504,6 +505,7 @@ action("robolectric_tests") {
     "test/io/flutter/plugins/GeneratedPluginRegistrant.java",
     "test/io/flutter/util/FakeKeyEvent.java",
     "test/io/flutter/util/PreconditionsTest.java",
+    "test/io/flutter/util/ViewUtilsTest.java",
     "test/io/flutter/view/AccessibilityBridgeTest.java",
   ]
 

shell/platform/android/io/flutter/util/ViewUtils.java

@@ -0,0 +1,31 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.util;
+
+import android.app.Activity;
+import android.content.Context;
+import android.content.ContextWrapper;
+
+public final class ViewUtils {
+  /**
+   * Retrieves the {@link Activity} from a given {@link Context}.
+   *
+   * <p>This method will recursively traverse up the context chain if it is a {@link ContextWrapper}
+   * until it finds the first instance of the base context that is an {@link Activity}.
+   */
+  public static Activity getActivity(Context context) {
+    if (context == null) {
+      return null;
+    }
+    if (context instanceof Activity) {
+      return (Activity) context;
+    }
+    if (context instanceof ContextWrapper) {
+      // Recurse up chain of base contexts until we find an Activity.
+      return getActivity(((ContextWrapper) context).getBaseContext());
+    }
+    return null;
+  }
+}

shell/platform/android/io/flutter/view/AccessibilityBridge.java

@@ -6,7 +6,9 @@
 
 import android.annotation.SuppressLint;
 import android.annotation.TargetApi;
+import android.app.Activity;
 import android.content.ContentResolver;
+import android.content.Context;
 import android.database.ContentObserver;
 import android.graphics.Rect;
 import android.net.Uri;
@@ -22,6 +24,7 @@
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.WindowInsets;
+import android.view.WindowManager;
 import android.view.accessibility.AccessibilityEvent;
 import android.view.accessibility.AccessibilityManager;
 import android.view.accessibility.AccessibilityNodeInfo;
@@ -35,6 +38,7 @@
 import io.flutter.embedding.engine.systemchannels.AccessibilityChannel;
 import io.flutter.plugin.platform.PlatformViewsAccessibilityDelegate;
 import io.flutter.util.Predicate;
+import io.flutter.util.ViewUtils;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.nio.charset.Charset;
@@ -1507,18 +1511,29 @@ void updateSemantics(
     if (rootObject != null) {
       final float[] identity = new float[16];
       Matrix.setIdentityM(identity, 0);
-      // in android devices API 23 and above, the system nav bar can be placed on the left side
+      // In Android devices API 23 and above, the system nav bar can be placed on the left side
       // of the screen in landscape mode. We must handle the translation ourselves for the
       // a11y nodes.
       if (Build.VERSION.SDK_INT >= 23) {
-        WindowInsets insets = rootAccessibilityView.getRootWindowInsets();
-        if (insets != null) {
-          if (!lastLeftFrameInset.equals(insets.getSystemWindowInsetLeft())) {
-            rootObject.globalGeometryDirty = true;
-            rootObject.inverseTransformDirty = true;
+        boolean needsToApplyLeftCutoutInset = true;
+        // In Android devices API 28 and above, the `layoutInDisplayCutoutMode` window attribute
+        // can be set to allow overlapping content within the cutout area. Query the attribute
+        // to figure out whether the content overlaps with the cutout and decide whether to
+        // apply cutout inset.
+        if (Build.VERSION.SDK_INT >= 28) {
+          needsToApplyLeftCutoutInset = doesLayoutInDisplayCutoutModeRequireLeftInset();
+        }
+
+        if (needsToApplyLeftCutoutInset) {
+          WindowInsets insets = rootAccessibilityView.getRootWindowInsets();
+          if (insets != null) {
+            if (!lastLeftFrameInset.equals(insets.getSystemWindowInsetLeft())) {
+              rootObject.globalGeometryDirty = true;
+              rootObject.inverseTransformDirty = true;
+            }
+            lastLeftFrameInset = insets.getSystemWindowInsetLeft();
+            Matrix.translateM(identity, 0, lastLeftFrameInset, 0, 0);
           }
-          lastLeftFrameInset = insets.getSystemWindowInsetLeft();
-          Matrix.translateM(identity, 0, lastLeftFrameInset, 0, 0);
         }
       }
       rootObject.updateRecursively(identity, visitedObjects, false);
@@ -1822,6 +1837,29 @@ private AccessibilityEvent obtainAccessibilityEvent(int virtualViewId, int event
     return event;
   }
 
+  /**
+   * Reads the {@code layoutInDisplayCutoutMode} value from the window attribute and returns whether
+   * a left cutout inset is required.
+   *
+   * <p>The {@code layoutInDisplayCutoutMode} is added after API level 28.
+   */
+  @TargetApi(28)
+  @RequiresApi(28)
+  private boolean doesLayoutInDisplayCutoutModeRequireLeftInset() {
+    Context context = rootAccessibilityView.getContext();
+    Activity activity = ViewUtils.getActivity(context);
+    if (activity == null || activity.getWindow() == null) {
+      // The activity is not visible, it does not matter whether to apply left inset
+      // or not.
+      return false;
+    }
+    int layoutInDisplayCutoutMode = activity.getWindow().getAttributes().layoutInDisplayCutoutMode;
+    return layoutInDisplayCutoutMode
+            == WindowManager.LayoutParams.LAYOUT_IN_DISPLAY_CUTOUT_MODE_NEVER
+        || layoutInDisplayCutoutMode
+            == WindowManager.LayoutParams.LAYOUT_IN_DISPLAY_CUTOUT_MODE_DEFAULT;
+  }
+
   /**
    * Hook called just before a {@link SemanticsNode} is removed from the Android cache of Flutter's
    * semantics tree.

shell/platform/android/io/flutter/view/FlutterView.java

@@ -8,7 +8,6 @@
 import android.annotation.TargetApi;
 import android.app.Activity;
 import android.content.Context;
-import android.content.ContextWrapper;
 import android.content.res.Configuration;
 import android.graphics.Bitmap;
 import android.graphics.Insets;
@@ -65,6 +64,7 @@
 import io.flutter.plugin.mouse.MouseCursorPlugin;
 import io.flutter.plugin.platform.PlatformPlugin;
 import io.flutter.plugin.platform.PlatformViewsController;
+import io.flutter.util.ViewUtils;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.List;
@@ -162,7 +162,7 @@ public FlutterView(Context context, AttributeSet attrs) {
   public FlutterView(Context context, AttributeSet attrs, FlutterNativeView nativeView) {
     super(context, attrs);
 
-    Activity activity = getActivity(getContext());
+    Activity activity = ViewUtils.getActivity(getContext());
     if (activity == null) {
       throw new IllegalArgumentException("Bad context");
     }
@@ -257,20 +257,6 @@ public void onPostResume() {
     sendUserPlatformSettingsToDart();
   }
 
-  private static Activity getActivity(Context context) {
-    if (context == null) {
-      return null;
-    }
-    if (context instanceof Activity) {
-      return (Activity) context;
-    }
-    if (context instanceof ContextWrapper) {
-      // Recurse up chain of base contexts until we find an Activity.
-      return getActivity(((ContextWrapper) context).getBaseContext());
-    }
-    return null;
-  }
-
   @NonNull
   public DartExecutor getDartExecutor() {
     return dartExecutor;

shell/platform/android/test/io/flutter/util/ViewUtilsTest.java

@@ -0,0 +1,33 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.util;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.mock;
+
+import android.app.Activity;
+import android.content.Context;
+import android.content.ContextWrapper;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.annotation.Config;
+
+@Config(manifest = Config.NONE)
+@RunWith(RobolectricTestRunner.class)
+public class ViewUtilsTest {
+  @Test
+  public void canGetActivity() {
+    // Non activity context returns null
+    Context nonActivityContext = mock(Context.class);
+    assertEquals(null, ViewUtils.getActivity(nonActivityContext));
+
+    Activity activity = mock(Activity.class);
+    assertEquals(activity, ViewUtils.getActivity(activity));
+
+    ContextWrapper wrapper = new ContextWrapper(new ContextWrapper(activity));
+    assertEquals(activity, ViewUtils.getActivity(wrapper));
+  }
+}