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

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 ;
+    }
+}