1 /*
2  * Copyright (C) 2018 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.permissioncontroller;
18 
19 import android.os.AsyncTask;
20 
21 import androidx.annotation.WorkerThread;
22 import androidx.lifecycle.LiveData;
23 
24 /**
25  * {@link LiveData} that uses {@link AsyncTask} to load value on a background thread.
26  *
27  * @param <T> type of the value
28  */
29 public abstract class AsyncTaskLiveData<T> extends LiveData<T> {
30 
31     /**
32      * Load the value on a background thread. The value will be reloaded even if already loaded.
33      */
loadValue()34     public void loadValue() {
35         AsyncTask.execute(() -> postValue(loadValueInBackground()));
36     }
37 
38     @WorkerThread
loadValueInBackground()39     protected abstract T loadValueInBackground();
40 }
41