英文:
Data store preferences is not working with Kotlin and Coroutines
问题
我想保存所选的数据库模式并显示当前模式。
英文:
I have a problem with data store preferences. I trying to save chosen database mode and display the current one in the settings screen, but I don't know why it's not working. I don't have any errors. I tried debugging the code, but the debugger is not going into the coroutine block.
class SettingsRepository @Inject constructor(private val dataStore: DataStore<Preferences>) {val databaseMode: Flow<String?>get() =dataStore.data.map { preferences ->preferences[DATABASE_MODE_KEY]}suspend fun updateDatabaseMode(databaseMode: String) {dataStore.edit { preferences ->preferences[DATABASE_MODE_KEY] = databaseMode}}companion object {val DATABASE_MODE_KEY = stringPreferencesKey("database_mode")}}
@HiltViewModelclass SettingsViewModel @Inject constructor(private val settingsRepository: SettingsRepository) : ViewModel() {private val _settingsState = MutableStateFlow(SettingsState())var settingsState: StateFlow<SettingsState> = _settingsState.asStateFlow()init {viewModelScope.launch {settingsRepository.databaseMode.map { mode ->_settingsState.update {it.copy(databaseMode = mode ?: DatabaseMode.LOCAL.name)}}}}fun onChangeDatabaseMode(databaseMode: String) {viewModelScope.launch {settingsRepository.updateDatabaseMode(databaseMode)}_settingsState.update {it.copy(databaseMode = databaseMode,showDatabaseModeDropdown = false)}}[...]
I want to save the chosen database mode and display the current one.
答案1
得分: 0
根据您的代码，我看到databaseMode流程从未被收集，所以init块中的map从未被调用。
我建议在这种情况下使用combine来合并databaseMode和settingsState流程。
可以像这样：
val databaseModeFlow = settingsRepository.databaseModeval combinedFlow = settingsState.combine(databaseModeFlow) { s, d ->s.copy(databaseMode = d)}
并且应该移除init块。
英文:
As I can see in you code databaseMode flow is never collected so map in init block never called.
I would suggest using combine for databaseMode and settingsState flows in this case.
Something like this:
val databaseModeFlow = settingsRepository.databaseModeval combinedFlow = settingsState.combine(databaseMode){ s, d ->s.copy(databaseMode = d)}
And init block should be removed.
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