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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.settingslib.core.AbstractPreferenceController;
     24 import com.android.settingslib.core.lifecycle.Lifecycle;
     25 import com.android.settingslib.core.lifecycle.LifecycleObserver;
     26 import com.android.settingslib.core.lifecycle.events.OnResume;
     27 
     28 public abstract class DynamicAvailabilityPreferenceController extends AbstractPreferenceController
     29         implements PreferenceControllerMixin, LifecycleObserver, OnResume {
     30 
     31     private Preference mPreference;
     32     private PreferenceScreen mScreen;
     33     private PreferenceAvailabilityObserver mAvailabilityObserver = null;
     34 
     35     public DynamicAvailabilityPreferenceController(Context context, Lifecycle lifecycle) {
     36         super(context);
     37         if (lifecycle != null) {
     38             lifecycle.addObserver(this);
     39         }
     40     }
     41 
     42     public void setAvailabilityObserver(PreferenceAvailabilityObserver observer) {
     43         mAvailabilityObserver = observer;
     44     }
     45 
     46     public PreferenceAvailabilityObserver getAvailabilityObserver() {
     47         return mAvailabilityObserver;
     48     }
     49 
     50     @Override
     51     public void displayPreference(PreferenceScreen screen) {
     52         mScreen = screen;
     53         mPreference = screen.findPreference(getPreferenceKey());
     54         super.displayPreference(screen);
     55     }
     56 
     57     @Override
     58     public void onResume() {
     59         if (!isAvailable()) {
     60             removePreference(mScreen, getPreferenceKey());
     61             return;
     62         }
     63 
     64         updateState(mPreference);
     65         if (mScreen.findPreference(getPreferenceKey()) == null) {
     66             mScreen.addPreference(mPreference);
     67         }
     68     }
     69 
     70     protected void notifyOnAvailabilityUpdate(boolean available) {
     71         if (mAvailabilityObserver != null) {
     72             mAvailabilityObserver.onPreferenceAvailabilityUpdated(getPreferenceKey(), available);
     73         }
     74     }
     75 }
     76