如何使用 Jetpack Compose 在 GlanceAppWidget 类中创建 Room Dao 或 Repository 或 Viewmodel 的实例

Question

我正在尝试使用 jetpack compose 加载 App Widget 中的数据列表，并且我已存储在 Room Local 数据库中，如何检索 GlanceAppWidget 类中的数据。

Answer 1

您需要使用 GlanceAppWidgetReceiver 类。您可以创建协程并访问您的域层。之后，您可以找到 GlanceAppWidget 类并将数据发送到您的小部件类。请查看这篇文章的完整示例：https:/ /medium.com/better-programming/android-jetpack-glance-for-app-widgets-bd7a704624ba

@AndroidEntryPoint
class MarketWidgetReceiver : GlanceAppWidgetReceiver() {

    override val glanceAppWidget: GlanceAppWidget = MarketWidget()

    private val coroutineScope = MainScope()

    @Inject
    lateinit var marketInformationUseCase: MarketInformationUseCase

    override fun onUpdate(
        context: Context,
        appWidgetManager: AppWidgetManager,
        appWidgetIds: IntArray
    ) {
        super.onUpdate(context, appWidgetManager, appWidgetIds)
        observeData(context)
    }

    override fun onReceive(context: Context, intent: Intent) {
        super.onReceive(context, intent)
        if (intent.action == MarketRefreshCallback.UPDATE_ACTION) {
            observeData(context)
        }
    }
    
    private fun observeData(context: Context) {
        coroutineScope.launch {

            val marketInformation =
                marketInformationUseCase.getMarketInformation(MarketInformationTimespan.TIMESPAN_1DAYS)

            val glanceId =
                GlanceAppWidgetManager(context).getGlanceIds(MarketWidget::class.java).firstOrNull()

            glanceId?.let {
                updateAppWidgetState(context, PreferencesGlanceStateDefinition, it) { pref ->
                    pref.toMutablePreferences().apply {
                        this[currentPrice] =
                            marketInformation.currentPrice
                        this[changeRate] =
                            marketInformation.changeRate
                        this[isChangeRatePositive] =
                            marketInformation.changeStatus == MarketInformationChangeStatus.POSITIVE
                    }
                }
                glanceAppWidget.update(context, it)
            }
        }
    }

    companion object {
        val currentPrice = stringPreferencesKey("currentPrice")
        val changeRate = stringPreferencesKey("changeRate")
        val isChangeRatePositive = booleanPreferencesKey("isChangeRatePositive")
    }

}