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 package androidx.lifecycle
17 
18 import android.app.Application
19 
20 /**
21  * Application context aware [ViewModel].
22  *
23  * Subclasses must have a constructor which accepts [Application] as the only parameter.
24  */
25 public open class AndroidViewModel(private val application: Application) : ViewModel() {
26 
27     /** Return the application. */
28     @Suppress("UNCHECKED_CAST")
getApplicationnull29     public open fun <T : Application> getApplication(): T {
30         return application as T
31     }
32 }
33 
34 /**
35  * The underlying [Application] inside [AndroidViewModel]
36  *
37  * One common hierarchy, such as KotlinViewModel <: JavaViewModel <: [AndroidViewModel], exposes
38  * private property `application` incorrectly. It is now fixed in K2 (Kotlin language version 2.0),
39  * but not backward compatible. This `inline` extension will make compilations of both pre- and
40  * post- 2.0 go well.
41  */
42 public inline val AndroidViewModel.application: Application
43     get() = getApplication()
44