由不同键写入触发的 Android DataStore 读取-解网

问：

通过查看文档 DataStore，我进行了设置

build.gradle.kts

implementation ("androidx.datastore:datastore-preferences:1.0.0")

MainActivity.kt （英语）

val Context.dataStore: DataStore<Preferences> by preferencesDataStore(name = "settings")
class MainActivity : ComponentActivity() {

override fun onCreate(savedInstanceState: Bundle?) {

    val MY_COUNTER_1 = intPreferencesKey("my_counter_1")
    val MY_COUNTER_2 = intPreferencesKey("my_counter_2")

    lifecycleScope.launch {
        dataStore.data
            .map { currentPreferences ->
                // Unlike Proto DataStore, there's no type safety here.
                currentPreferences[MY_COUNTER_1] ?: 0
            }.collect {
                Log.d("MainActivity", "Counter 1: $it")
            }
    }

    lifecycleScope.launch {
        dataStore.data
            .map { currentPreferences ->
                // Unlike Proto DataStore, there's no type safety here.
                currentPreferences[MY_COUNTER_2] ?: 0
            }.collect {
                Log.d("MainActivity", "Counter 2: $it")
            }
    }

    lifecycleScope.launch {
        while (true) {
            dataStore.edit { currentPreferences ->
                val currentCounterValue = currentPreferences[MY_COUNTER_2] ?: 0
                currentPreferences[MY_COUNTER_2] = currentCounterValue + 1
            }
            delay(3000)
        }
    }

我发现当用新值写入时，也会触发读取。我希望只读，我是否错误地配置了我的 DataStore？MY_COUNTER_2MY_COUNTER_1MY_COUNTER_2

Android 协程数据存储

这听起来像是每当任何值发生变化时都会发出一个新值。新发出的值将是一个对象，该对象保存存储在中的所有当前首选项。然后，您可以按其键过滤所需的首选项，并将始终处理该值，即使该值实际上没有更改。FlowDataStoreDataStorecollect

如果只想在特定首选项实际更改时才显示该首选项的值，请尝试使用 distinctUntilChanged 函数：collect

 dataStore.data
    .map { currentPreferences ->
        currentPreferences[MY_COUNTER_1] ?: 0
    }.distinctUntilChanged().collect {
        Log.d("MainActivity", "Counter 1: $it")
    }

由不同键写入触发的 Android DataStore 读取

Android DataStore read triggered by different key write

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