1 /* <lambda>null2 * 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.ui.viewmodel 18 19 import com.android.compose.animation.scene.UserAction 20 import com.android.compose.animation.scene.UserActionResult 21 import com.android.systemui.lifecycle.ExclusiveActivatable 22 import kotlinx.coroutines.awaitCancellation 23 import kotlinx.coroutines.flow.MutableStateFlow 24 import kotlinx.coroutines.flow.StateFlow 25 import kotlinx.coroutines.flow.asStateFlow 26 27 /** 28 * Base class for view-models that need to keep a map of user actions up-to-date. 29 * 30 * Subclasses need only to override [hydrateActions], suspending forever if they need; they don't 31 * need to worry about resetting the value of [actions] when the view-model is deactivated/canceled, 32 * this base class takes care of it. 33 */ 34 abstract class UserActionsViewModel : ExclusiveActivatable() { 35 36 private val _actions = MutableStateFlow<Map<UserAction, UserActionResult>>(emptyMap()) 37 /** 38 * [UserActionResult] by [UserAction] to be collected by the scene container to enable the right 39 * user input/gestures. 40 */ 41 val actions: StateFlow<Map<UserAction, UserActionResult>> = _actions.asStateFlow() 42 43 final override suspend fun onActivated(): Nothing { 44 try { 45 hydrateActions { state -> _actions.value = state } 46 awaitCancellation() 47 } finally { 48 _actions.value = emptyMap() 49 } 50 } 51 52 /** 53 * Keeps the user actions up-to-date (AKA "hydrated"). 54 * 55 * Subclasses should implement this `suspend fun` by running coroutine work and calling 56 * [setActions] each time the actions should be published/updated. The work can safely suspend 57 * forever; the base class will take care of canceling it as needed. There's no need to handle 58 * cancellation in this method. 59 * 60 * The base class will also take care of resetting the [actions] flow back to the default value 61 * when this happens. 62 */ 63 protected abstract suspend fun hydrateActions( 64 setActions: (Map<UserAction, UserActionResult>) -> Unit, 65 ) 66 } 67