android - CalledFromWrongThreadException 即使使用 AndroidSchedulers.mainThread()

Question

好的，我们实现了一个 MVP 层，很好地展示并使用 RxJava 和 RxAndroid。我们拍了this作为例子并以此为基础。

当 Presenter 被调用开始执行时，它会向 Model Interactor 提交一个 Subscriber。 Interactor 创建一个 Observable 并设置 observeOn(Schedulers.io()) 和 subscribeOn(AndroidSchedulers.mainThread())。这样(我们认为)当调用返回到 Subscriber(在 Presenter 中)时，每个调用都将在 UI 线程上进行。在 Subscriber 中，我们将数据绑定(bind)到 View 。但是，这会引发 CalledFromWrongThreadException:

07-28 09:12:48.844  17424    17566         AndroidRuntime  E  FATAL EXCEPTION: RxCachedThreadScheduler-1
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  Process: [PACKAGE NAME], PID: 17424
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  java.lang.IllegalStateException: Fatal Exception thrown on Scheduler.Worker thread.
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:62)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:422)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at java.util.concurrent.FutureTask.run(FutureTask.java:237)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:152)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:265)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at java.lang.Thread.run(Thread.java:818)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  Caused by: rx.exceptions.OnErrorFailedException: Error occurred when trying to propagate error to Observer.onError
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at rx.observers.SafeSubscriber._onError(SafeSubscriber.java:201)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at rx.observers.SafeSubscriber.onError(SafeSubscriber.java:111)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at rx.observers.SafeSubscriber.onNext(SafeSubscriber.java:137)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at rx.internal.operators.OperatorSubscribeOn$1$1$1.onNext(OperatorSubscribeOn.java:76)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at rx.internal.operators.NotificationLite.accept(NotificationLite.java:150)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at rx.internal.operators.OperatorObserveOn$ObserveOnSubscriber.pollQueue(OperatorObserveOn.java:205)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at rx.internal.operators.OperatorObserveOn$ObserveOnSubscriber$2.call(OperatorObserveOn.java:159)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  ... 7 more
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  Caused by: rx.exceptions.CompositeException: 2 exceptions occurred.
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  ... 15 more
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  Caused by: rx.exceptions.CompositeException$CompositeExceptionCausalChain: Chain of Causes for CompositeException In Order Received =>
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at android.util.Log.getStackTraceString(Log.java:499)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at com.android.internal.os.RuntimeInit.Clog_e(RuntimeInit.java:59)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at com.android.internal.os.RuntimeInit.access$200(RuntimeInit.java:43)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at com.android.internal.os.RuntimeInit$UncaughtHandler.uncaughtException(RuntimeInit.java:91)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at java.lang.ThreadGroup.uncaughtException(ThreadGroup.java:693)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at java.lang.ThreadGroup.uncaughtException(ThreadGroup.java:690)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:66)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  ... 7 more
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  Caused by: java.lang.IllegalStateException: Method call should happen from the main thread.
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at com.squareup.picasso.Utils.checkMain(Utils.java:136)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at com.squareup.picasso.RequestCreator.into(RequestCreator.java:615)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at com.squareup.picasso.RequestCreator.into(RequestCreator.java:601)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at com.nextmarkets.next.education.view.TradingIdeaHistoryFragment.setCoachAvatar(TradingIdeaHistoryFragment.java:94)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at com.nextmarkets.next.education.TradingIdeaHistoryPresenter$TradingIdeaHistorySubscriber.onNext(TradingIdeaHistoryPresenter.java:55)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at com.nextmarkets.next.education.TradingIdeaHistoryPresenter$TradingIdeaHistorySubscriber.onNext(TradingIdeaHistoryPresenter.java:38)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at rx.observers.SafeSubscriber.onNext(SafeSubscriber.java:130)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at rx.internal.operators.OperatorSubscribeOn$1$1$1.onNext(OperatorSubscribeOn.java:76)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at rx.internal.operators.NotificationLite.accept(NotificationLite.java:150)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at rx.internal.operators.OperatorObserveOn$ObserveOnSubscriber.pollQueue(OperatorObserveOn.java:205)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at rx.internal.operators.OperatorObserveOn$ObserveOnSubscriber$2.call(OperatorObserveOn.java:159)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  ... 7 more
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  Caused by: android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:7062)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at android.view.ViewRootImpl.requestChildFocus(ViewRootImpl.java:3098)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at android.view.ViewGroup.requestChildFocus(ViewGroup.java:678)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at android.view.ViewGroup.requestChildFocus(ViewGroup.java:678)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at android.view.ViewGroup.requestChildFocus(ViewGroup.java:678)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at android.view.ViewGroup.requestChildFocus(ViewGroup.java:678)
07-28 09:12:48.844  17424    17566         AndroidRuntime  E  at andro

堆栈跟踪实际上在此时中断。

当然，我们可以在 View 中手动在 UI 线程上运行它，但是当我们设置 subscribeOn(AndroidSchedulers.mainThread()) 时，这不是必需的，不是吗？我们之前已经毫无问题地做到了这一点。我们是否遗漏了什么？

一些更多的实现细节:我们将 Dagger2 用于 DI，Interactor 在 Module 中创建，并通过构造函数获取 Schedulers。

    @Provides
    MyInteractor provideMyInteractor() {
        return new MyInteractorImpl(Schedulers.io(), AndroidSchedulers.mainThread());
    }

Presenter通过构造函数注入(inject)获取Interactor，Presenter通过Component注入(inject)View。

Answer 1

不确定你在那里做什么，但只是提醒和澄清:

subscribeOn 方法指定执行 onSubscribe 方法的线程。

observeOn 方法指定将在其上执行 onNext/onError/onCompleted 的线程。

你是说 - “Interactor 创建一个 Observable 并设置 observeOn(Schedulers.io()) 和 subscribeOn(AndroidSchedulers.mainThread())。”您可能混淆了这两种方法。