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 
DynamicAvailabilityPreferenceController(Context context, Lifecycle lifecycle)34     public DynamicAvailabilityPreferenceController(Context context, Lifecycle lifecycle) {
35         super(context);
36         if (lifecycle != null) {
37             lifecycle.addObserver(this);
38         }
39     }
40 
setAvailabilityObserver(PreferenceAvailabilityObserver observer)41     public void setAvailabilityObserver(PreferenceAvailabilityObserver observer) {
42         mAvailabilityObserver = observer;
43     }
44 
getAvailabilityObserver()45     public PreferenceAvailabilityObserver getAvailabilityObserver() {
46         return mAvailabilityObserver;
47     }
48 
49     @Override
displayPreference(PreferenceScreen screen)50     public void displayPreference(PreferenceScreen screen) {
51         mScreen = screen;
52         mPreference = screen.findPreference(getPreferenceKey());
53         super.displayPreference(screen);
54     }
55 
56     @Override
onResume()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 
notifyOnAvailabilityUpdate(boolean available)69     protected void notifyOnAvailabilityUpdate(boolean available) {
70         if (mAvailabilityObserver != null) {
71             mAvailabilityObserver.onPreferenceAvailabilityUpdated(getPreferenceKey(), available);
72         }
73     }
74 }
75