RxJava：正确地捕获异常(RxJava: catch exception properly)

 我试图在调度程序IO线程中执行一些IO操作，并且如果抛出异常，我想向用户显示一些Toast。 
 
 为此，我使用以下代码： 
 
Observable.interval(0, 15, TimeUnit.SECONDS)
            .observeOn(Schedulers.io())
            .doOnNext(event -> new Repository().inputOutput(MainActivity.this);)
            .observeOn(AndroidSchedulers.mainThread())
            .doOnError(throwable -> 
                    Toast.makeText(MainActivity.this, "Error message", Toast.LENGTH_SHORT).show())
            .subscribe();
 
 当在方法“inputOutput”上引发异常时，我期望Throwable能够在“doOnError”使用者中捕获，但它不会发生，并且将异常抛出到周围的代码中。 
 
 我什么都错了？ 非常感谢你！ 

I am trying to perform some IO operation in the Schedulers IO thread, and if an exception is thrown, I want to show some Toast to the user.
 
For this I use the following code:
 
Observable.interval(0, 15, TimeUnit.SECONDS)
            .observeOn(Schedulers.io())
            .doOnNext(event -> new Repository().inputOutput(MainActivity.this);)
            .observeOn(AndroidSchedulers.mainThread())
            .doOnError(throwable -> 
                    Toast.makeText(MainActivity.this, "Error message", Toast.LENGTH_SHORT).show())
            .subscribe();
 
When an exception is thrown on method "inputOutput", I expect the Throwable to be catched in the "doOnError" consumer, but it doesn't happen and the exception is thrown to the surrounding code.
 
What am I doint wrong? Thank you very much!

原文：https://stackoverflow.com/questions/48850153