Disable system alert window permissions on low ram devices

Bug: 63697002
Bug: 117832554
Test: adb am start-activity -a
android.settings.action.MANAGE_OVERLAY_PERMISSION
Change-Id: I44c64001cd07fd4934cdc55f455384cebd5c9cfb

res/layout/manage_applications_apps_unsupported.xml

@@ -0,0 +1,56 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2019 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+
+<androidx.coordinatorlayout.widget.CoordinatorLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:settings="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:gravity="center"
+        android:orientation="vertical">
+
+        <TextView
+            android:id="@+id/empty_header"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="@string/disabled_feature"
+            android:textAppearance="?android:attr/textAppearanceLarge"/>
+
+        <TextView
+            android:id="@+id/empty_body"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="@string/disabled_feature_reason_slow_down_phone"
+            android:textAppearance="?android:attr/textAppearanceSmall"/>
+
+        <com.google.android.material.appbar.AppBarLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content">
+            <FrameLayout
+                android:id="@+id/pinned_header"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                settings:layout_scrollFlags="scroll|enterAlways"/>
+        </com.google.android.material.appbar.AppBarLayout>
+
+    </LinearLayout>
+
+</androidx.coordinatorlayout.widget.CoordinatorLayout>

res/values/strings.xml

@@ -10183,6 +10183,10 @@
 
     <!-- Note displayed when certain features are not available on low ram devices. [CHAR LIMIT=NONE] -->
     <string name="disabled_low_ram_device">This feature is not available on this device</string>
+    <!-- Note displayed when certain features are not available. [CHAR LIMIT=NONE] -->
+    <string name="disabled_feature">This feature is not available</string>
+    <!-- Note displayed to explain that a feature is not available because it will slow down the phone. [CHAR LIMIT=NONE] -->
+    <string name="disabled_feature_reason_slow_down_phone">It will slow down this phone</string>
 
     <!-- UI debug setting: preference title - enforce full raw GNSS satellite measurements [CHAR LIMIT=60] -->
     <string name="enable_gnss_raw_meas_full_tracking">Force full GNSS measurements</string>

res/xml/special_access.xml

@@ -42,7 +42,8 @@
         android:key="system_alert_window"
         android:title="@string/system_alert_window_settings"
         android:fragment="com.android.settings.applications.manageapplications.ManageApplications"
-        settings:keywords="@string/keywords_system_alert_window">
+        settings:keywords="@string/keywords_system_alert_window"
+        settings:controller="com.android.settings.applications.specialaccess.SystemAlertWindowPreferenceController">
         <extra
             android:name="classname"
             android:value="com.android.settings.Settings$OverlaySettingsActivity" />

src/com/android/settings/Utils.java

@@ -55,6 +55,7 @@ import android.net.LinkProperties;
 import android.net.Network;
 import android.net.wifi.WifiManager;
 import android.os.BatteryManager;
+import android.os.Build;
 import android.os.Bundle;
 import android.os.IBinder;
 import android.os.INetworkManagementService;
@@ -1007,4 +1008,14 @@ public final class Utils extends com.android.settingslib.Utils {
             return context.getResources();
         }
     }
+
+    /**
+     * Returns true if SYSTEM_ALERT_WINDOW permission is available.
+     * Starting from Q, SYSTEM_ALERT_WINDOW is disabled on low ram phones.
+     */
+    public static boolean isSystemAlertWindowEnabled(Context context) {
+        // SYSTEM_ALERT_WINDOW is disabled on on low ram devices starting from Q
+        ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
+        return !(am.isLowRamDevice() && (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q));
+    }
 }

src/com/android/settings/applications/appinfo/DrawOverlayDetails.java

@@ -17,6 +17,7 @@ package com.android.settings.applications.appinfo;
 
 import static android.view.WindowManager.LayoutParams.SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS;
 
+import android.app.ActivityManager;
 import android.app.AppOpsManager;
 import android.app.settings.SettingsEnums;
 import android.content.Context;
@@ -25,6 +26,9 @@ import android.content.pm.PackageManager;
 import android.content.pm.ResolveInfo;
 import android.os.Bundle;
 import android.provider.Settings;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
 import android.view.Window;
 import android.view.WindowManager;
 
@@ -36,6 +40,7 @@ import androidx.preference.Preference.OnPreferenceClickListener;
 import androidx.preference.SwitchPreference;
 
 import com.android.settings.R;
+import com.android.settings.Utils;
 import com.android.settings.applications.AppInfoWithHeader;
 import com.android.settings.applications.AppStateAppOpsBridge.PermissionState;
 import com.android.settings.applications.AppStateOverlayBridge;
@@ -70,6 +75,11 @@ public class DrawOverlayDetails extends AppInfoWithHeader implements OnPreferenc
         mOverlayBridge = new AppStateOverlayBridge(context, mState, null);
         mAppOpsManager = (AppOpsManager) context.getSystemService(Context.APP_OPS_SERVICE);
 
+        if (!Utils.isSystemAlertWindowEnabled(context)) {
+            mPackageInfo = null;
+            return;
+        }
+
         // find preferences
         addPreferencesFromResource(R.xml.draw_overlay_permissions_details);
         mSwitchPref = (SwitchPreference) findPreference(KEY_APP_OPS_SETTINGS_SWITCH);
@@ -81,6 +91,18 @@ public class DrawOverlayDetails extends AppInfoWithHeader implements OnPreferenc
                 .setAction(Settings.ACTION_MANAGE_OVERLAY_PERMISSION);
     }
 
+    // Override here so we don't have an empty screen
+    @Override
+    public View onCreateView (LayoutInflater inflater,
+            ViewGroup container,
+            Bundle savedInstanceState) {
+        // if we don't have a package info, show a page saying this is unsupported
+        if (mPackageInfo == null) {
+            return inflater.inflate(R.layout.manage_applications_apps_unsupported, null);
+        }
+        return super.onCreateView(inflater, container, savedInstanceState);
+    }
+
     @Override
     public void onResume() {
         super.onResume();
@@ -142,6 +164,8 @@ public class DrawOverlayDetails extends AppInfoWithHeader implements OnPreferenc
 
     @Override
     protected boolean refreshUi() {
+        if (mPackageInfo == null) return true;
+
         mOverlayState = mOverlayBridge.getOverlayInfo(mPackageName,
                 mPackageInfo.applicationInfo.uid);
 

src/com/android/settings/applications/manageapplications/ManageApplications.java

@@ -33,6 +33,7 @@ import static com.android.settings.applications.manageapplications.AppFilterRegi
 import android.annotation.Nullable;
 import android.annotation.StringRes;
 import android.app.Activity;
+import android.app.ActivityManager;
 import android.app.settings.SettingsEnums;
 import android.app.usage.IUsageStatsManager;
 import android.content.Context;
@@ -49,18 +50,22 @@ import android.text.TextUtils;
 import android.util.ArraySet;
 import android.util.IconDrawableFactory;
 import android.util.Log;
+import android.util.TypedValue;
+import android.view.Gravity;
 import android.view.LayoutInflater;
 import android.view.Menu;
 import android.view.MenuInflater;
 import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
+import android.view.ViewGroup.LayoutParams;
 import android.widget.AdapterView;
 import android.widget.AdapterView.OnItemSelectedListener;
 import android.widget.Filter;
 import android.widget.FrameLayout;
 import android.widget.SearchView;
 import android.widget.Spinner;
+import android.widget.TextView;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.VisibleForTesting;
@@ -79,6 +84,7 @@ import com.android.settings.Settings.StorageUseActivity;
 import com.android.settings.Settings.UsageAccessSettingsActivity;
 import com.android.settings.Settings.WriteSettingsActivity;
 import com.android.settings.SettingsActivity;
+import com.android.settings.Utils;
 import com.android.settings.applications.AppInfoBase;
 import com.android.settings.applications.AppStateAppOpsBridge.PermissionState;
 import com.android.settings.applications.AppStateBaseBridge;
@@ -327,12 +333,19 @@ public class ManageApplications extends InstrumentedFragment
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container,
             Bundle savedInstanceState) {
+        if (mListType == LIST_TYPE_OVERLAY && !Utils.isSystemAlertWindowEnabled(getContext())) {
+            mRootView = inflater.inflate(R.layout.manage_applications_apps_unsupported, null);
+            setHasOptionsMenu(false);
+            return mRootView;
+        }
+
         mRootView = inflater.inflate(R.layout.manage_applications_apps, null);
         mLoadingContainer = mRootView.findViewById(R.id.loading_container);
         mListContainer = mRootView.findViewById(R.id.list_container);
         if (mListContainer != null) {
             // Create adapter and list view here
             mEmptyView = mListContainer.findViewById(android.R.id.empty);
+
             mApplications = new ApplicationsAdapter(mApplicationsState, this, mFilter,
                     savedInstanceState);
             if (savedInstanceState != null) {

src/com/android/settings/applications/specialaccess/SystemAlertWindowPreferenceController.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.settings.applications.specialaccess;
+
+import static com.android.settings.Utils.isSystemAlertWindowEnabled;
+
+import android.app.ActivityManager;
+import android.content.Context;
+import android.os.Build;
+
+import com.android.settings.core.BasePreferenceController;
+
+public class SystemAlertWindowPreferenceController extends BasePreferenceController {
+    public SystemAlertWindowPreferenceController(Context context, String preferenceKey) {
+        super(context, preferenceKey);
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return isSystemAlertWindowEnabled(mContext)
+                ? AVAILABLE_UNSEARCHABLE : UNSUPPORTED_ON_DEVICE ;
+    }
+}

tests/robotests/src/com/android/settings/applications/specialaccess/SystemAlertWindowPreferenceControllerTest.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.applications.specialaccess;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.content.Context;
+
+import com.android.settings.testutils.shadow.ShadowUtils;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+import org.robolectric.annotation.Config;
+
+@RunWith(RobolectricTestRunner.class)
+@Config(shadows = {ShadowUtils.class})
+public class SystemAlertWindowPreferenceControllerTest {
+
+    private Context mContext;
+    private SystemAlertWindowPreferenceController mController;
+
+    @Before
+    public void setUp() {
+        mContext = RuntimeEnvironment.application;
+        mController = new SystemAlertWindowPreferenceController(mContext, "key");
+    }
+
+    @Test
+    public void systemAlertWindow_byDefault_shouldBeShown() {
+        ShadowUtils.setIsSystemAlertWindowEnabled(true);
+        assertThat(mController.isAvailable()).isTrue();
+    }
+
+    @Test
+    public void systemAlertWindow_lowMemory_shouldNotBeShown() {
+        ShadowUtils.setIsSystemAlertWindowEnabled(false);
+        assertThat(mController.isAvailable()).isFalse();
+    }
+}

tests/robotests/src/com/android/settings/testutils/shadow/ShadowUtils.java

@@ -38,6 +38,7 @@ public class ShadowUtils {
     private static boolean sIsDemoUser;
     private static ComponentName sDeviceOwnerComponentName;
     private static Map<String, String> sAppNameMap;
+    private static boolean sIsSystemAlertWindowEnabled;
 
     @Implementation
     protected static int enforceSameOwner(Context context, int userId) {
@@ -113,4 +114,13 @@ public class ShadowUtils {
         }
         sAppNameMap.put(packageName, appLabel);
     }
+
+    @Implementation
+    protected static boolean isSystemAlertWindowEnabled(Context context) {
+        return sIsSystemAlertWindowEnabled;
+    }
+
+    public static void setIsSystemAlertWindowEnabled(boolean enabled) {
+        sIsSystemAlertWindowEnabled = enabled;
+    }
 }