用例:我需要从用户那里获得反馈,将其保存在持久存储中,在本例中为Room。每 X 分钟后,我想将这些存储的FeedbackRequest
发送到后端。
解决方案:我想使用WorkManager,因为此操作应该在进程死亡中幸存下来,并且也会定期触发。我需要从 Room DB 获取FeedbackRequest
列表并使用 Retrofit 客户端将每个FeedbackRequest
发送到后端。
问题定义:FeedbackRequestRepository
负责获取FeedbackRequest
列表,在 WorkManager 的doWork()
方法中需要从房间 DB 获取数据。另外,我对Dagger2
很陌生。打开应用程序后,我收到上述错误。
应用组件代码片段
interface AppComponent {
@Component.Builder
interface Builder {
@BindsInstance
fun application(application: Application): Builder
fun build(): AppComponent
}
fun inject(scFeedbackApp: ScFeedbackApp)
fun inject(dispatchWorker: DispatchWorker)
}
存储库代码片段
@Singleton
class FeedbackRequestRepository @Inject constructor(
private val appExecutors: AppExecutors,
private val db: ScFeedbackDB,
private val feedbackAcknowledgeDao: FeedbackRequestDao,
private val scFeedbackFeedbackService: SCFeedbackService
) {
...
}
工作线程代码段
class DispatchWorker @Inject constructor(context:Context,
workerParameters: WorkerParameters,
var feedbackRequestRepository: FeedbackRequestRepository):
Worker(context, workerParameters){
init {
DaggerAppComponent.builder().application(context.applicationContext as ScFeedbackApp)
.build().inject(this)
}
override fun doWork(): Result {
...
}
错误
E/WorkerFactory: Could not instantiate com.scfeedback.service.responseDispatcher.DispatchWorker
java.lang.NoSuchMethodException: <init> [class android.content.Context, class androidx.work.WorkerParameters]
at java.lang.Class.getConstructor(Class.java:528)
at java.lang.Class.getDeclaredConstructor(Class.java:507)
at androidx.work.WorkerFactory.createWorkerWithDefaultFallback(WorkerFactory.java:85)
at androidx.work.impl.WorkerWrapper.runWorker(WorkerWrapper.java:188)
at androidx.work.impl.WorkerWrapper.run(WorkerWrapper.java:124)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
at java.lang.Thread.run(Thread.java:818)
E/WorkerWrapper: Could not create Worker com.scfeedback.service.responseDispatcher.DispatchWorker
- 这与依赖关系注入设置有关吗?
- 如果没有,那我哪里错了。
您的方法存在两个问题:
- 不能同时应用构造函数注入
@inject constructor(...)
和直接注入DaggerAppComponent...inject(this)
- 必须使用默认构造函数:
因此,您可以将DispatchWorker
更改为:
class DispatchWorker constructor(context:Context,
workerParameters: WorkerParameters):
Worker(context, workerParameters){
@Inject lateinit var feedbackRequestRepository: FeedbackRequestRepository
init {
DaggerAppComponent.builder().application(context.applicationContext as ScFeedbackApp)
.build().inject(this)
}
override fun doWork(): Result {
...
}
或使用自定义工人工厂