Kotlin中 StateFlow 或 SharedFlow 的区别解析

// 定义 StateFlow（通常在 ViewModel 中）
private val _counterState = MutableStateFlow(0) // 初始值 0
val counterState: StateFlow<Int> = _counterState.asStateFlow()
// 更新值
fun increment() {
    _counterState.value++ // 自动通知所有订阅者
}
// 在 Activity/Fragment 中监听
lifecycleScope.launch {
    viewModel.counterState.collect { value ->
        textView.text = "Count: $value"
    }
}

// 定义 SharedFlow（通常在 ViewModel 中）
private val _toastEvent = MutableSharedFlow<String>() // 无初始值
val toastEvent: SharedFlow<String> = _toastEvent.asSharedFlow()
// 发送事件
fun showToast(message: String) {
    viewModelScope.launch {
        _toastEvent.emit(message) // 发送事件
    }
}
// 在 Activity/Fragment 中监听
lifecycleScope.launch {
    viewModel.toastEvent.collect { message ->
        Toast.makeText(this, message, Toast.LENGTH_SHORT).show()
    }
}

/**
     * 应用中心数据变化，更新应用中心小组件的显示
     */
    private fun WidgetSelectorViewModel.observerAppList() = coroutineScope.launch {
        appWidgets.onEach { list ->
            Log.d(TAG, "observerAppList setDataList")
            gridAdapterApp.setDataList(list)
            appItemBinding?.groupNoData?.isVisible = list.isEmpty()
        }.launchIn(coroutineScope)
    }  

private fun WidgetSelectorViewModel.observerAppList() = coroutineScope.launch {

appWidgets.onEach { list ->
    gridAdapterApp.setDataList(list)
    appItemBinding?.groupNoData?.isVisible = list.isEmpty()
}.launchIn(coroutineScope)