Евгений s's questions

我想使用 Dagger Hilt 依赖注入运行PeriodicWork。但是，它不会定期工作。我已经检查过我的代码很多次了。尽管我希望每秒收到一条消息，但最多只有一条成功完成工作的消息。

这是 MainActivity 的代码：

@AndroidEntryPoint
class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setContent {
            RunARepeatableWorkUsingWorkManagerTheme {

            val lifecycleOwner = LocalLifecycleOwner.current

            LaunchedEffect(key1 = Unit ){

                val workRequest = PeriodicWorkRequestBuilder<CustomWorker>(
                    repeatInterval = 1,
                    repeatIntervalTimeUnit = TimeUnit.SECONDS,)
                    .setBackoffCriteria(
                        backoffPolicy = BackoffPolicy.LINEAR,
                        duration = Duration.ofSeconds(5))
                    .build()

                    val workManager = WorkManager.getInstance(applicationContext)
                    workManager.enqueueUniquePeriodicWork("myWork", ExistingPeriodicWorkPolicy.KEEP, workRequest)

                     workManager.getWorkInfosForUniqueWorkLiveData("myWork")
                    .observe(lifecycleOwner){ it ->
                        it.forEach {workInfo ->
                        Log.d("MyWorker: MainActivity", "${workInfo.state}")
                    }
                }
            }
            }
        }
    }
}   

我的工人看起来像这样：

@HiltWorker
class CustomWorker @AssistedInject constructor(
    @Assisted context: Context,
    @Assisted workerParameters: WorkerParameters
) : CoroutineWorker(context, workerParameters){
        override suspend fun doWork(): Result {
            try {
                println("MyWorker : The result or the worker is Success")
                return Result.success()
            } catch (e: Exception) {
                Log.e("MyWorker: CustomWorker", "Worker failed: ${e.message}", e)
                return Result.failure()
            }
        }
}

HiltAndroidApp是：

@HiltAndroidApp
class AppInstance : Application(), Configuration.Provider{
    @Inject lateinit var workerFactory: HiltWorkerFactory

    override fun getWorkManagerConfiguration() =
        Configuration.Builder()
            .setWorkerFactory(workerFactory)
            .build()

}

另外，我在清单文件中添加了：

<provider
    android:name="androidx.startup.InitializationProvider"
    android:authorities="${applicationId}.androidx-startup"
    android:exported="false"
    tools:node="merge"
    >
    <meta-data
        android:name="androidx.work.impl.WorkManagerInitializer"
        android:value="androidx.startup"
        tools:node="remove" />
</provider>

Logcat 仅显示：

 2023-09-24 18:16:46.712  4819-4819  MyWorker: MainActivity  com...epeatableworkusingworkmanager  D  ENQUEUED
2023-09-24 18:17:47.375  4819-4854  System.out              com...epeatableworkusingworkmanager  I  MyWorker : The result or the worker is Success
2023-09-24 18:17:47.429  4819-4819  MyWorker: MainActivity  com...epeatableworkusingworkmanager  D  RUNNING
2023-09-24 18:17:47.437  4819-4819  MyWorker: MainActivity  com...epeatableworkusingworkmanager  D  ENQUEUED

就这样。问题是：为什么我看不到每秒都在完成工作的消息？我将不胜感激任何帮助！

当我从数据库下载信息时，收集函数不会停止发射（Kotlin 的收集函数不会自行终止。）

我有这个实体类：

@Entity
data class ShareEntity(
    @PrimaryKey(autoGenerate = false)
    val secId: String,
    val shortName: String,
    val fullName: String = "",
    val isFavorite: Boolean
)

通过 Dao 中的“isFavorite”获取特定的所有共享的函数如下所示：

@Dao
interface DataBaseDao {
………..
@Query("SELECT * FROM ShareEntity WHERE isFavorite =:isFavorite")
fun getAllSharesByIsFavorite(isFavorite: Boolean): Flow<List<ShareEntity>>
}

在 DataBaseDao 中，还有许多其他函数可以将一些数据插入到 ShareEntity 实体中。

为了使用 Dao 接口，创建了 DataBaseRepository 及其实现 DataBaseRepositoryIm：

interface DataBaseRepository {
………..
fun getAllSharesByIsFavorite(isFavorite: Boolean): Flow<List<ShareEntity>>
}

class DataBaseRepositoryIm(
private val dataBaseDao: DataBaseDao
) : DataBaseRepository{
………..
override fun getAllSharesByIsFavorite(isFavorite: Boolean): Flow<List<ShareEntity>> {
 return dataBaseDao.getAllSharesByIsFavorite(isFavorite)
}
}

在我的 NewsScreenViewModel1 中，我有一个通过“isFavorite”加载所有共享的函数

@HiltViewModel
class NewsScreenViewModel1 @Inject constructor(
    private val dataBaseRepository: DataBaseRepository,
    private val repository: ApiRepository,
) : ViewModel(){

suspend fun downloadListOfSharesByIsFavorite(isFavorite: Boolean = true){
 val shares = dataBaseRepository.getAllSharesByIsFavorite(isFavorite).collect{ it:List<ShareEntity> ->
 println("NewsScreenVM1: allShares is with isFavorite = $isFavorite are $it")
 println("NewsScreenVM1: the size of shares is ${it.size}")
 }
 println("NewsScreenVM1: Now we are outside of the collect function")
}
}

在可组合的 NewsScreen 中，我使用 LauncheEffect 启动该函数：

@Composable
fun NewsScreen(
    NewsScreenViewModel1: NewsScreenViewModel1 = hiltViewModel()
) {
    LaunchedEffect(key1 = Unit) {
        NewsScreenViewModel1.downloadListOfSharesByIsFavorite()
    }

}

问题是收集函数不会自行终止，或者换句话说，它不会停止。在 LogCat 中我看到：

“NewsScreenVM1：allShares isFavorite = true 为 [ShareEntity(secId=ALRS,shortName=АЛРОСАао,fullName=,isFavorite=true),ShareEntity(secId=AGRO,shortName=AGRO-гдр,fullName=,isFavorite=true), ShareEntity（secId = AFLT，shortName = Аэрофлот，fullName =，isFavorite = true），ShareEntity（secId = FEES，shortName = Россети，fullName =，isFavorite = true）]”

“NewsScreenVM1：份额大小为 4”

并且没有：“NewsScreenVM1：现在我们位于收集功能之外”，这意味着收集功能尚未停止其发射并且仍在运行。

我做错了什么？为什么从数据库收集一些数据后无法执行代码行？

我尝试在不同的协程范围上运行流程，如下所示：

fun downloadListOfSharesByIsFavorite(isFavorite: Boolean = true){
 viewModelScope.launch { 
val shares = dataBaseRepository.getAllSharesByIsFavorite(isFavorite).collect{ it:List<ShareEntity> -> 
println("NewsScreenVM1: allShares is with isFavorite = $isFavorite are $it")
println("NewsScreenVM1: the size of shares is ${it.size}")
}
println("NewsScreenVM1: Now we are outside of the collect function")
}
}

但是消息“NewsScreenVM1：现在我们位于收集函数之外”出现在所有计算之前，这不是我想要的。我希望这是最后一次按摩。

当我将异步函数与 .await() 结合使用时，我也没有收到最后一条消息，因为流程永远不会停止。这是代码：

suspend fun downloadListOfSharesByIsFavorite(isFavorite: Boolean = true) {
        val asyncValue = viewModelScope.async {
            var size = 0
            val shares = dataBaseRepository.getAllSharesByIsFavorite(isFavorite)
                .collect { it: List<ShareEntity> ->
                    println("NewsScreenVM1: allShares is with isFavorite = $isFavorite are $it")
                    println("NewsScreenVM1: the size of shares is ${it.size}")
                    size = it.size

                }
            size
        }
            println("NewsScreenVM1: Now we are outside of the collect function. The list size is ${asyncValue.await()}")
        }