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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.settings.development;
     18 
     19 import android.app.ActivityManager;
     20 import android.app.IActivityManager;
     21 import android.content.Context;
     22 import android.os.RemoteException;
     23 import android.support.annotation.VisibleForTesting;
     24 import android.support.v7.preference.ListPreference;
     25 import android.support.v7.preference.Preference;
     26 
     27 import com.android.settings.R;
     28 import com.android.settings.core.PreferenceControllerMixin;
     29 import com.android.settingslib.development.DeveloperOptionsPreferenceController;
     30 
     31 public class BackgroundProcessLimitPreferenceController extends
     32         DeveloperOptionsPreferenceController implements Preference.OnPreferenceChangeListener,
     33         PreferenceControllerMixin {
     34 
     35     private static final String APP_PROCESS_LIMIT_KEY = "app_process_limit";
     36 
     37     private final String[] mListValues;
     38     private final String[] mListSummaries;
     39 
     40     public BackgroundProcessLimitPreferenceController(Context context) {
     41         super(context);
     42 
     43         mListValues = context.getResources().getStringArray(R.array.app_process_limit_values);
     44         mListSummaries = context.getResources().getStringArray(R.array.app_process_limit_entries);
     45     }
     46 
     47     @Override
     48     public String getPreferenceKey() {
     49         return APP_PROCESS_LIMIT_KEY;
     50     }
     51 
     52     @Override
     53     public boolean onPreferenceChange(Preference preference, Object newValue) {
     54         writeAppProcessLimitOptions(newValue);
     55         updateAppProcessLimitOptions();
     56         return true;
     57     }
     58 
     59     @Override
     60     public void updateState(Preference preference) {
     61         updateAppProcessLimitOptions();
     62     }
     63 
     64     @Override
     65     protected void onDeveloperOptionsSwitchDisabled() {
     66         super.onDeveloperOptionsSwitchDisabled();
     67         writeAppProcessLimitOptions(null);
     68     }
     69 
     70     private void updateAppProcessLimitOptions() {
     71         try {
     72             final int limit = getActivityManagerService().getProcessLimit();
     73             int index = 0; // default
     74             for (int i = 0; i < mListValues.length; i++) {
     75                 int val = Integer.parseInt(mListValues[i]);
     76                 if (val >= limit) {
     77                     index = i;
     78                     break;
     79                 }
     80             }
     81             final ListPreference listPreference = (ListPreference) mPreference;
     82             listPreference.setValue(mListValues[index]);
     83             listPreference.setSummary(mListSummaries[index]);
     84         } catch (RemoteException e) {
     85             // intentional no-op
     86         }
     87     }
     88 
     89     private void writeAppProcessLimitOptions(Object newValue) {
     90         try {
     91             final int limit = newValue != null ? Integer.parseInt(newValue.toString()) : -1;
     92             getActivityManagerService().setProcessLimit(limit);
     93             updateAppProcessLimitOptions();
     94         } catch (RemoteException e) {
     95             // intentional no-op
     96         }
     97     }
     98 
     99     @VisibleForTesting
    100     IActivityManager getActivityManagerService() {
    101         return ActivityManager.getService();
    102     }
    103 }
    104