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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.core;
     18 
     19 import android.content.Context;
     20 import android.support.v7.preference.Preference;
     21 import android.support.v7.preference.PreferenceScreen;
     22 
     23 import com.android.settings.core.lifecycle.Lifecycle;
     24 import com.android.settings.core.lifecycle.LifecycleObserver;
     25 import com.android.settings.core.lifecycle.events.OnResume;
     26 
     27 public abstract class DynamicAvailabilityPreferenceController extends PreferenceController
     28         implements LifecycleObserver, OnResume {
     29 
     30     private Preference mPreference;
     31     private PreferenceScreen mScreen;
     32     private PreferenceAvailabilityObserver mAvailabilityObserver = null;
     33 
     34     public DynamicAvailabilityPreferenceController(Context context, Lifecycle lifecycle) {
     35         super(context);
     36         if (lifecycle != null) {
     37             lifecycle.addObserver(this);
     38         }
     39     }
     40 
     41     public void setAvailabilityObserver(PreferenceAvailabilityObserver observer) {
     42         mAvailabilityObserver = observer;
     43     }
     44 
     45     public PreferenceAvailabilityObserver getAvailabilityObserver() {
     46         return mAvailabilityObserver;
     47     }
     48 
     49     @Override
     50     public void displayPreference(PreferenceScreen screen) {
     51         mScreen = screen;
     52         mPreference = screen.findPreference(getPreferenceKey());
     53         super.displayPreference(screen);
     54     }
     55 
     56     @Override
     57     public void onResume() {
     58         if (!isAvailable()) {
     59             removePreference(mScreen, getPreferenceKey());
     60             return;
     61         }
     62 
     63         updateState(mPreference);
     64         if (mScreen.findPreference(getPreferenceKey()) == null) {
     65             mScreen.addPreference(mPreference);
     66         }
     67     }
     68 
     69     protected void notifyOnAvailabilityUpdate(boolean available) {
     70         if (mAvailabilityObserver != null) {
     71             mAvailabilityObserver.onPreferenceAvailabilityUpdated(getPreferenceKey(), available);
     72         }
     73     }
     74 }
     75