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 /**
19  * Callback interface for listening to [LifecycleOwner] state changes. If a class implements both
20  * this interface and [LifecycleEventObserver], then methods of `DefaultLifecycleObserver` will be
21  * called first, and then followed by the call of [LifecycleEventObserver.onStateChanged]
22  *
23  * If a class implements this interface and in the same time uses [OnLifecycleEvent], then
24  * annotations will be ignored.
25  */
26 public interface DefaultLifecycleObserver : LifecycleObserver {
27     /**
28      * Notifies that `ON_CREATE` event occurred.
29      *
30      * This method will be called after the [LifecycleOwner]'s `onCreate` method returns.
31      *
32      * @param owner the component, whose state was changed
33      */
onCreatenull34     public fun onCreate(owner: LifecycleOwner) {}
35 
36     /**
37      * Notifies that `ON_START` event occurred.
38      *
39      * This method will be called after the [LifecycleOwner]'s `onStart` method returns.
40      *
41      * @param owner the component, whose state was changed
42      */
onStartnull43     public fun onStart(owner: LifecycleOwner) {}
44 
45     /**
46      * Notifies that `ON_RESUME` event occurred.
47      *
48      * This method will be called after the [LifecycleOwner]'s `onResume` method returns.
49      *
50      * @param owner the component, whose state was changed
51      */
onResumenull52     public fun onResume(owner: LifecycleOwner) {}
53 
54     /**
55      * Notifies that `ON_PAUSE` event occurred.
56      *
57      * This method will be called before the [LifecycleOwner]'s `onPause` method is called.
58      *
59      * @param owner the component, whose state was changed
60      */
onPausenull61     public fun onPause(owner: LifecycleOwner) {}
62 
63     /**
64      * Notifies that `ON_STOP` event occurred.
65      *
66      * This method will be called before the [LifecycleOwner]'s `onStop` method is called.
67      *
68      * @param owner the component, whose state was changed
69      */
onStopnull70     public fun onStop(owner: LifecycleOwner) {}
71 
72     /**
73      * Notifies that `ON_DESTROY` event occurred.
74      *
75      * This method will be called before the [LifecycleOwner]'s `onDestroy` method is called.
76      *
77      * @param owner the component, whose state was changed
78      */
onDestroynull79     public fun onDestroy(owner: LifecycleOwner) {}
80 }
81