1 /*
2  * Copyright (C) 2024 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.systemui.scene.shared.model
18 
19 import com.android.compose.animation.scene.SceneKey
20 import com.android.compose.animation.scene.TransitionKey
21 import kotlinx.coroutines.flow.StateFlow
22 
23 /** Defines interface for classes that provide access to scene state. */
24 interface SceneDataSource {
25 
26     /**
27      * The current scene, as seen by the real data source in the UI layer.
28      *
29      * During a transition between two scenes, the original scene will still be reflected in
30      * [currentScene] until a time when the UI layer decides to commit the change, which is when
31      * [currentScene] will have the value of the target/new scene.
32      */
33     val currentScene: StateFlow<SceneKey>
34 
35     /**
36      * Asks for an asynchronous scene switch to [toScene], which will use the corresponding
37      * installed transition or the one specified by [transitionKey], if provided.
38      */
changeScenenull39     fun changeScene(
40         toScene: SceneKey,
41         transitionKey: TransitionKey? = null,
42     )
43 
44     /**
45      * Asks for an instant scene switch to [toScene], without an animated transition of any kind.
46      */
47     fun snapToScene(
48         toScene: SceneKey,
49     )
50 }
51