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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.notification;
     18 
     19 import android.content.ContentResolver;
     20 import android.content.Context;
     21 
     22 import android.database.ContentObserver;
     23 import android.net.Uri;
     24 import android.os.Handler;
     25 import android.support.v7.preference.Preference;
     26 import android.support.v7.preference.PreferenceScreen;
     27 
     28 import com.android.internal.annotations.VisibleForTesting;
     29 import com.android.settings.SettingsPreferenceFragment;
     30 import com.android.settings.core.PreferenceController;
     31 import com.android.settings.core.lifecycle.Lifecycle;
     32 import com.android.settings.core.lifecycle.LifecycleObserver;
     33 import com.android.settings.core.lifecycle.events.OnPause;
     34 import com.android.settings.core.lifecycle.events.OnResume;
     35 import java.util.List;
     36 
     37 public abstract class SettingPrefController extends PreferenceController implements
     38     LifecycleObserver, OnResume, OnPause {
     39 
     40     protected static final int DEFAULT_ON = 1;
     41 
     42     private SettingsPreferenceFragment mParent;
     43     protected SettingsObserver mSettingsObserver;
     44     protected SettingPref mPreference;
     45 
     46     public SettingPrefController(Context context, SettingsPreferenceFragment parent,
     47             Lifecycle lifecycle) {
     48         super(context);
     49         mParent = parent;
     50         if (lifecycle != null) {
     51             lifecycle.addObserver(this);
     52         }
     53     }
     54 
     55     @Override
     56     public void displayPreference(PreferenceScreen screen) {
     57         mPreference.init(mParent);
     58         if (isAvailable()) {
     59             mSettingsObserver = new SettingsObserver();
     60         }
     61     }
     62 
     63     @Override
     64     public String getPreferenceKey() {
     65         return mPreference.getKey();
     66     }
     67 
     68     @Override
     69     public boolean isAvailable() {
     70         return mPreference.isApplicable(mContext);
     71     }
     72 
     73     @Override
     74     public void updateState(Preference preference) {
     75         mPreference.update(mContext);
     76     }
     77 
     78     @Override
     79     public void onResume() {
     80         if (mSettingsObserver != null) {
     81             mSettingsObserver.register(true /* register */);
     82         }
     83     }
     84 
     85     @Override
     86     public void onPause() {
     87         if (mSettingsObserver != null) {
     88             mSettingsObserver.register(false /* register */);
     89         }
     90     }
     91 
     92     @VisibleForTesting
     93     final class SettingsObserver extends ContentObserver {
     94         public SettingsObserver() {
     95             super(new Handler());
     96         }
     97 
     98         public void register(boolean register) {
     99             final ContentResolver cr = mContext.getContentResolver();
    100             if (register) {
    101                 cr.registerContentObserver(mPreference.getUri(), false, this);
    102             } else {
    103                 cr.unregisterContentObserver(this);
    104             }
    105         }
    106 
    107         @Override
    108         public void onChange(boolean selfChange, Uri uri) {
    109             super.onChange(selfChange, uri);
    110             if (mPreference.getUri().equals(uri)) {
    111                 mPreference.update(mContext);
    112             }
    113         }
    114     }
    115 
    116 }
    117