From 1a38d2e54be3a6ea7ec6b2d24670d30bbd8e53e7 Mon Sep 17 00:00:00 2001
From: chunhtai <47866232+chunhtai@users.noreply.github.com>
Date: Fri, 19 Aug 2022 13:54:47 -0700
Subject: [PATCH] Updates accessible_navigation trigger in Android
 (flutter/engine#35478)

* Updates accessible_navigation trigger in Android

* update doc comments

* comment

* addressing comment
---
 .../io/flutter/view/AccessibilityBridge.java  | 34 ++++++++++++++---
 .../flutter/view/AccessibilityBridgeTest.java | 38 +++++++++++++++++++
 2 files changed, 66 insertions(+), 6 deletions(-)

diff --git a/engine/src/flutter/shell/platform/android/io/flutter/view/AccessibilityBridge.java b/engine/src/flutter/shell/platform/android/io/flutter/view/AccessibilityBridge.java
index 28b09507214..6168954f58b 100644
--- a/engine/src/flutter/shell/platform/android/io/flutter/view/AccessibilityBridge.java
+++ b/engine/src/flutter/shell/platform/android/io/flutter/view/AccessibilityBridge.java
@@ -257,6 +257,30 @@ public class AccessibilityBridge extends AccessibilityNodeProvider {
 
   @Nullable private OnAccessibilityChangeListener onAccessibilityChangeListener;
 
+  // Whether the users are using assistive technologies to interact with the devices.
+  //
+  // The getter returns true when at least one of the assistive technologies is running:
+  // TalkBack, SwitchAccess, or VoiceAccess.
+  @VisibleForTesting
+  public boolean getAccessibleNavigation() {
+    return accessibleNavigation;
+  }
+
+  private boolean accessibleNavigation = false;
+
+  private void setAccessibleNavigation(boolean value) {
+    if (accessibleNavigation == value) {
+      return;
+    }
+    accessibleNavigation = value;
+    if (accessibleNavigation) {
+      accessibilityFeatureFlags |= AccessibilityFeature.ACCESSIBLE_NAVIGATION.value;
+    } else {
+      accessibilityFeatureFlags &= ~AccessibilityFeature.ACCESSIBLE_NAVIGATION.value;
+    }
+    sendLatestAccessibilityFlagsToFlutter();
+  }
+
   // Set to true after {@code release} has been invoked.
   private boolean isReleased = false;
 
@@ -331,6 +355,7 @@ public class AccessibilityBridge extends AccessibilityNodeProvider {
                 accessibilityChannel.setAccessibilityMessageHandler(accessibilityMessageHandler);
                 accessibilityChannel.onAndroidAccessibilityEnabled();
               } else {
+                setAccessibleNavigation(false);
                 accessibilityChannel.setAccessibilityMessageHandler(null);
                 accessibilityChannel.onAndroidAccessibilityDisabled();
               }
@@ -409,7 +434,6 @@ public class AccessibilityBridge extends AccessibilityNodeProvider {
     this.contentResolver = contentResolver;
     this.accessibilityViewEmbedder = accessibilityViewEmbedder;
     this.platformViewsAccessibilityDelegate = platformViewsAccessibilityDelegate;
-
     // Tell Flutter whether accessibility is initially active or not. Then register a listener
     // to be notified of changes in the future.
     accessibilityStateChangeListener.onAccessibilityStateChanged(accessibilityManager.isEnabled());
@@ -425,13 +449,10 @@ public class AccessibilityBridge extends AccessibilityNodeProvider {
               if (isReleased) {
                 return;
               }
-              if (isTouchExplorationEnabled) {
-                accessibilityFeatureFlags |= AccessibilityFeature.ACCESSIBLE_NAVIGATION.value;
-              } else {
+              if (!isTouchExplorationEnabled) {
+                setAccessibleNavigation(false);
                 onTouchExplorationExit();
-                accessibilityFeatureFlags &= ~AccessibilityFeature.ACCESSIBLE_NAVIGATION.value;
               }
-              sendLatestAccessibilityFlagsToFlutter();
 
               if (onAccessibilityChangeListener != null) {
                 onAccessibilityChangeListener.onAccessibilityChanged(
@@ -551,6 +572,7 @@ public class AccessibilityBridge extends AccessibilityNodeProvider {
   // Suppressing Lint warning for new API, as we are version guarding all calls to newer APIs
   @SuppressLint("NewApi")
   public AccessibilityNodeInfo createAccessibilityNodeInfo(int virtualViewId) {
+    setAccessibleNavigation(true);
     if (virtualViewId >= MIN_ENGINE_GENERATED_NODE_ID) {
       // The node is in the engine generated range, and is provided by the accessibility view
       // embedder.
diff --git a/engine/src/flutter/shell/platform/android/test/io/flutter/view/AccessibilityBridgeTest.java b/engine/src/flutter/shell/platform/android/test/io/flutter/view/AccessibilityBridgeTest.java
index 324331d9d18..155401992df 100644
--- a/engine/src/flutter/shell/platform/android/test/io/flutter/view/AccessibilityBridgeTest.java
+++ b/engine/src/flutter/shell/platform/android/test/io/flutter/view/AccessibilityBridgeTest.java
@@ -124,6 +124,44 @@ public class AccessibilityBridgeTest {
     assertEquals(position, outBoundsInScreen.top);
   }
 
+  @Test
+  public void itSetsAccessibleNavigation() {
+    AccessibilityChannel mockChannel = mock(AccessibilityChannel.class);
+    AccessibilityViewEmbedder mockViewEmbedder = mock(AccessibilityViewEmbedder.class);
+    AccessibilityManager mockManager = mock(AccessibilityManager.class);
+    View mockRootView = mock(View.class);
+    Context context = mock(Context.class);
+    when(mockRootView.getContext()).thenReturn(context);
+    when(context.getPackageName()).thenReturn("test");
+    when(mockManager.isTouchExplorationEnabled()).thenReturn(false);
+    AccessibilityBridge accessibilityBridge =
+        setUpBridge(
+            /*rootAccessibilityView=*/ mockRootView,
+            /*accessibilityChannel=*/ mockChannel,
+            /*accessibilityManager=*/ mockManager,
+            /*contentResolver=*/ null,
+            /*accessibilityViewEmbedder=*/ mockViewEmbedder,
+            /*platformViewsAccessibilityDelegate=*/ null);
+    ArgumentCaptor<AccessibilityManager.TouchExplorationStateChangeListener> listenerCaptor =
+        ArgumentCaptor.forClass(AccessibilityManager.TouchExplorationStateChangeListener.class);
+    verify(mockManager).addTouchExplorationStateChangeListener(listenerCaptor.capture());
+
+    assertEquals(accessibilityBridge.getAccessibleNavigation(), false);
+    verify(mockChannel).setAccessibilityFeatures(0);
+    reset(mockChannel);
+
+    // Simulate assistive technology accessing accessibility tree.
+    accessibilityBridge.createAccessibilityNodeInfo(0);
+    verify(mockChannel).setAccessibilityFeatures(1);
+    assertEquals(accessibilityBridge.getAccessibleNavigation(), true);
+
+    // Simulate turning off TalkBack.
+    reset(mockChannel);
+    listenerCaptor.getValue().onTouchExplorationStateChanged(false);
+    verify(mockChannel).setAccessibilityFeatures(0);
+    assertEquals(accessibilityBridge.getAccessibleNavigation(), false);
+  }
+
   @Test
   public void itDoesNotContainADescriptionIfScopesRoute() {
     AccessibilityBridge accessibilityBridge = setUpBridge();