Make magnification mode switch accessible

To support accessibility of magnification mode switch,
We provide content description, state description and
click action.

Bug: 168278448
Test: Enable Talkback to do manually test
      atest MagnificationModeSwitchTest

Change-Id: I1b94f3849f85db4f6dc2b801d0dd6ff40d0c87ed

3 files changed, 92 insertions, 7 deletions

diff --git a/packages/SystemUI/res/values/strings.xml b/packages/SystemUI/res/values/strings.xml
index 2427d36076c5..b08ec130b760 100644
--- a/packages/SystemUI/res/values/strings.xml
+++ b/packages/SystemUI/res/values/strings.xml
@@ -2678,6 +2678,14 @@
     <string name="accessibility_control_move_left">Move left</string>
     <!-- Action in accessibility menu to move the magnification window right. [CHAR LIMIT=30] -->
     <string name="accessibility_control_move_right">Move right</string>
+    <!-- Content description for magnification mode switch. [CHAR LIMIT=NONE] -->
+    <string name="magnification_mode_switch_description">Magnification switch</string>
+    <!-- A11y state description for magnification mode switch that device is in full-screen mode. [CHAR LIMIT=NONE] -->
+    <string name="magnification_mode_switch_state_full_screen">Magnify entire screen</string>
+    <!-- A11y state description for magnification mode switch that device is in window mode. [CHAR LIMIT=NONE] -->
+    <string name="magnification_mode_switch_state_window">Magnify part of screen</string>
+    <!-- Click action label for magnification switch. [CHAR LIMIT=NONE] -->
+    <string name="magnification_mode_switch_click_label">Switch</string>
 
     <!-- Device Controls strings -->
     <!-- Device Controls empty state, title [CHAR LIMIT=30] -->
diff --git a/packages/SystemUI/src/com/android/systemui/accessibility/MagnificationModeSwitch.java b/packages/SystemUI/src/com/android/systemui/accessibility/MagnificationModeSwitch.java
index 68e404e36bba..1af38970ea4c 100644
--- a/packages/SystemUI/src/com/android/systemui/accessibility/MagnificationModeSwitch.java
+++ b/packages/SystemUI/src/com/android/systemui/accessibility/MagnificationModeSwitch.java
@@ -16,11 +16,14 @@
 
 package com.android.systemui.accessibility;
 
+import static android.provider.Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE_WINDOW;
+
 import android.annotation.NonNull;
 import android.content.Context;
 import android.content.pm.ActivityInfo;
 import android.graphics.PixelFormat;
 import android.graphics.PointF;
+import android.os.Bundle;
 import android.provider.Settings;
 import android.util.MathUtils;
 import android.view.Gravity;
@@ -28,6 +31,8 @@ import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewConfiguration;
 import android.view.WindowManager;
+import android.view.accessibility.AccessibilityNodeInfo;
+import android.view.accessibility.AccessibilityNodeInfo.AccessibilityAction;
 import android.widget.ImageView;
 
 import com.android.internal.annotations.VisibleForTesting;
@@ -71,6 +76,29 @@ class MagnificationModeSwitch {
         applyResourcesValues();
         mImageView.setImageResource(getIconResId(mMagnificationMode));
         mImageView.setOnTouchListener(this::onTouch);
+        mImageView.setAccessibilityDelegate(new View.AccessibilityDelegate() {
+            @Override
+            public void onInitializeAccessibilityNodeInfo(View host, AccessibilityNodeInfo info) {
+                super.onInitializeAccessibilityNodeInfo(host, info);
+                info.setStateDescription(formatStateDescription());
+                info.setContentDescription(mContext.getResources().getString(
+                        R.string.magnification_mode_switch_description));
+                final AccessibilityAction clickAction = new AccessibilityAction(
+                        AccessibilityAction.ACTION_CLICK.getId(), mContext.getResources().getString(
+                        R.string.magnification_mode_switch_click_label));
+                info.addAction(clickAction);
+                info.setClickable(true);
+            }
+
+            @Override
+            public boolean performAccessibilityAction(View host, int action, Bundle args) {
+                if (action == AccessibilityAction.ACTION_CLICK.getId()) {
+                    handleSingleTap();
+                    return true;
+                }
+                return super.performAccessibilityAction(host, action, args);
+            }
+        });
 
         mAnimationTask = () -> {
             mImageView.animate()
@@ -81,6 +109,13 @@ class MagnificationModeSwitch {
         };
     }
 
+    private CharSequence formatStateDescription() {
+        final int stringId = mMagnificationMode == ACCESSIBILITY_MAGNIFICATION_MODE_WINDOW
+                ? R.string.magnification_mode_switch_state_window
+                : R.string.magnification_mode_switch_state_full_screen;
+        return mContext.getResources().getString(stringId);
+    }
+
     private void applyResourcesValues() {
         final int padding = mContext.getResources().getDimensionPixelSize(
                 R.dimen.magnification_switch_button_padding);
diff --git a/packages/SystemUI/tests/src/com/android/systemui/accessibility/MagnificationModeSwitchTest.java b/packages/SystemUI/tests/src/com/android/systemui/accessibility/MagnificationModeSwitchTest.java
index 64e067396059..0a51b26f4a85 100644
--- a/packages/SystemUI/tests/src/com/android/systemui/accessibility/MagnificationModeSwitchTest.java
+++ b/packages/SystemUI/tests/src/com/android/systemui/accessibility/MagnificationModeSwitchTest.java
@@ -22,11 +22,14 @@ import static android.view.MotionEvent.ACTION_CANCEL;
 import static android.view.MotionEvent.ACTION_DOWN;
 import static android.view.MotionEvent.ACTION_MOVE;
 import static android.view.MotionEvent.ACTION_UP;
+import static android.view.accessibility.AccessibilityNodeInfo.AccessibilityAction.ACTION_CLICK;
 
 import static com.android.systemui.accessibility.MagnificationModeSwitch.getIconResId;
 
 import static junit.framework.Assert.assertEquals;
 
+import static org.hamcrest.CoreMatchers.hasItems;
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyFloat;
 import static org.mockito.ArgumentMatchers.anyLong;
@@ -45,10 +48,12 @@ import android.view.View;
 import android.view.ViewConfiguration;
 import android.view.ViewPropertyAnimator;
 import android.view.WindowManager;
+import android.view.accessibility.AccessibilityNodeInfo;
 import android.widget.ImageView;
 
 import androidx.test.filters.SmallTest;
 
+import com.android.systemui.R;
 import com.android.systemui.SysuiTestCase;
 
 import org.junit.Before;
@@ -142,13 +147,7 @@ public class MagnificationModeSwitchTest extends SysuiTestCase {
         resetMockImageViewAndAnimator();
         listener.onTouch(mSpyImageView, MotionEvent.obtain(
                 0, ViewConfiguration.getTapTimeout(), ACTION_UP, 100, 100, 0));
-        verify(mViewPropertyAnimator).cancel();
-        verify(mSpyImageView).setImageResource(
-                getIconResId(ACCESSIBILITY_MAGNIFICATION_MODE_WINDOW));
-        verify(mWindowManager).removeView(mSpyImageView);
-        final int actualMode = Settings.Secure.getInt(mContext.getContentResolver(),
-                Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE, 0);
-        assertEquals(ACCESSIBILITY_MAGNIFICATION_MODE_WINDOW, actualMode);
+        verifyTapAction(ACCESSIBILITY_MAGNIFICATION_MODE_WINDOW);
     }
 
     @Test
@@ -222,6 +221,34 @@ public class MagnificationModeSwitchTest extends SysuiTestCase {
         assertShowButtonAnimation();
     }
 
+    @Test
+    public void initializeA11yNode_showWindowModeButton_expectedValues() {
+        mMagnificationModeSwitch.showButton(ACCESSIBILITY_MAGNIFICATION_MODE_WINDOW);
+        final AccessibilityNodeInfo nodeInfo = new AccessibilityNodeInfo();
+
+        mSpyImageView.onInitializeAccessibilityNodeInfo(nodeInfo);
+
+        assertEquals(mContext.getString(R.string.magnification_mode_switch_description),
+                nodeInfo.getContentDescription());
+        assertEquals(mContext.getString(R.string.magnification_mode_switch_state_window),
+                nodeInfo.getStateDescription());
+        assertThat(nodeInfo.getActionList(),
+                hasItems(new AccessibilityNodeInfo.AccessibilityAction(
+                        ACTION_CLICK.getId(), mContext.getResources().getString(
+                        R.string.magnification_mode_switch_click_label))));
+    }
+
+    @Test
+    public void performA11yActions_showWindowModeButton_verifyTapAction() {
+        mMagnificationModeSwitch.showButton(ACCESSIBILITY_MAGNIFICATION_MODE_WINDOW);
+        resetMockImageViewAndAnimator();
+
+        mSpyImageView.performAccessibilityAction(
+                ACTION_CLICK.getId(), null);
+
+        verifyTapAction(ACCESSIBILITY_MAGNIFICATION_MODE_FULLSCREEN);
+    }
+
     private void assertModeUnchanged(int expectedMode) {
         final int actualMode = Settings.Secure.getInt(mContext.getContentResolver(),
                 Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE, 0);
@@ -254,4 +281,19 @@ public class MagnificationModeSwitchTest extends SysuiTestCase {
         Mockito.reset(mSpyImageView);
         initMockImageViewAndAnimator();
     }
+
+    /**
+     * Verifies the tap behaviour including the image of the button and the magnification mode.
+     *
+     * @param expectedMode the expected mode after tapping
+     */
+    private void verifyTapAction(int expectedMode) {
+        verify(mViewPropertyAnimator).cancel();
+        verify(mSpyImageView).setImageResource(
+                getIconResId(expectedMode));
+        verify(mWindowManager).removeView(mSpyImageView);
+        final int actualMode = Settings.Secure.getInt(mContext.getContentResolver(),
+                Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE, 0);
+        assertEquals(expectedMode, actualMode);
+    }
 }