好的，我们实现了一个 MVP 层，很好地展示和使用 RxJava 和 RxAndroid。我们以此为例并以此为基础。
当 Presenter 被调用开始执行时，它Subscriber会向 Model Interactor 提交一个。交互器创建一个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 内）时，每个调用都将在 UI 线程上。在Subscriber我们将数据绑定到视图中。然而，这引发了一个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
堆栈跟踪实际上在这一点上被切断了。
当然，我们可以在 View 中手动在 UI 线程上运行它，但是当我们设置时，这应该不是必需的subscribeOn(AndroidSchedulers.mainThread())，不是吗？我们以前做过，没有问题。我们错过了什么吗？
更多实现细节：我们将 Dagger2 用于 DI，Interactor 是在一个Module并通过构造函数获取调度程序。
@Provides
MyInteractor provideMyInteractor() {
return new MyInteractorImpl(Schedulers.io(), AndroidSchedulers.mainThread());
}
Presenter通过构造函数注入获取Interactor，Presenter通过Component.