Do not allow draw on top for App notification settings

Fixes: 119115683
Test: manual
Change-Id: Ib7b878a23b4a99171c58b5de992fb87feca8a28a

src/com/android/settings/notification/AppNotificationSettings.java

@@ -16,6 +16,8 @@
 
 package com.android.settings.notification;
 
+import static android.view.WindowManager.LayoutParams.SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS;
+
 import android.app.NotificationChannel;
 import android.app.NotificationChannelGroup;
 import android.app.settings.SettingsEnums;
@@ -24,6 +26,8 @@ import android.os.AsyncTask;
 import android.os.Bundle;
 import android.text.TextUtils;
 import android.util.Log;
+import android.view.Window;
+import android.view.WindowManager;
 
 import androidx.preference.Preference;
 import androidx.preference.PreferenceCategory;
@@ -33,7 +37,6 @@ import androidx.preference.SwitchPreference;
 
 import com.android.internal.widget.LockPatternUtils;
 import com.android.settings.R;
-import com.android.settings.widget.MasterCheckBoxPreference;
 import com.android.settingslib.RestrictedSwitchPreference;
 import com.android.settingslib.core.AbstractPreferenceController;
 
@@ -85,6 +88,8 @@ public class AppNotificationSettings extends NotificationSettingsBase {
     public void onResume() {
         super.onResume();
 
+        getActivity().getWindow().addSystemFlags(SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS);
+
         if (mUid < 0 || TextUtils.isEmpty(mPkg) || mPkgInfo == null) {
             Log.w(TAG, "Missing package or uid or packageinfo");
             finish();
@@ -118,6 +123,15 @@ public class AppNotificationSettings extends NotificationSettingsBase {
         updatePreferenceStates();
     }
 
+    @Override
+    public void onPause() {
+        super.onPause();
+        final Window window = getActivity().getWindow();
+        final WindowManager.LayoutParams attrs = window.getAttributes();
+        attrs.privateFlags &= ~SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS;
+        window.setAttributes(attrs);
+    }
+
     @Override
     protected String getLogTag() {
         return TAG;

tests/robotests/src/com/android/settings/notification/AppNotificationSettingsTest.java

@@ -0,0 +1,93 @@
+package com.android.settings.notification;
+
+import static android.view.WindowManager.LayoutParams.SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.view.Window;
+import android.view.WindowManager;
+
+import androidx.fragment.app.FragmentActivity;
+import androidx.fragment.app.FragmentManager;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.Robolectric;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.annotation.Config;
+import org.robolectric.annotation.Implementation;
+import org.robolectric.annotation.Implements;
+
+@RunWith(RobolectricTestRunner.class)
+public class AppNotificationSettingsTest {
+
+    private WindowManager.LayoutParams mLayoutParams;
+    private AppNotificationSettings mFragment;
+    private FragmentActivity mActivity;
+    @Mock
+    private Window mWindow;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        mLayoutParams = new WindowManager.LayoutParams();
+        mActivity = spy(Robolectric.setupActivity(FragmentActivity.class));
+        mFragment = spy(new AppNotificationSettings());
+        when(mFragment.getActivity()).thenReturn(mActivity);
+        when(mFragment.getFragmentManager()).thenReturn(mock(FragmentManager.class));
+        when(mActivity.getWindow()).thenReturn(mWindow);
+        when(mWindow.getAttributes()).thenReturn(mLayoutParams);
+    }
+
+    @Test
+    @Config(shadows = {ShadowNotificationSettingsBase.class})
+    public void onResume_shouldHideSystemOverlay() {
+        mFragment.onResume();
+
+        verify(mWindow).addSystemFlags(SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS);
+    }
+
+    @Test
+    @Config(shadows = {ShadowNotificationSettingsBase.class})
+    public void onPause_shouldRemoveHideSystemOverlay() {
+        mFragment.onResume();
+
+        verify(mWindow).addSystemFlags(SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS);
+
+        mFragment.onPause();
+
+        // There's no Window.clearPrivateFlags() method, so the Window.attributes are updated.
+        ArgumentCaptor<WindowManager.LayoutParams> paramCaptor = ArgumentCaptor.forClass(
+                WindowManager.LayoutParams.class);
+        verify(mWindow).setAttributes(paramCaptor.capture());
+        assertEquals(0,
+                paramCaptor.getValue().privateFlags
+                        & SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS);
+    }
+
+    @Implements(NotificationSettingsBase.class)
+    public static class ShadowNotificationSettingsBase {
+
+        protected void __constructor__() {
+            // Do nothing
+        }
+
+        @Implementation
+        protected void onResume() {
+            // No-op.
+        }
+
+        @Implementation
+        protected void onPause() {
+            // No-op.
+        }
+    }
+}