处理程序消息中未捕获异常

Question

The situation is quite complicated, but I'll try to explain it. (The code is simplified from the real app)

I have a handler on a custom thread with a looper. I send a message to it:

...
handler.obtainMessage(...)
    .sendToTarget();
...

The handler has a message callback:

private final Handler.Callback callback = new Handler.Callback() {
    public boolean handleMessage(Message msg) {
            try {
                //The hard work is here
                SystemClock.sleep(5000)
                throw new CustomException();
            } catch (CustomException e) {

            }
            //...
            //Sending the result back to the UI thread here.
            //...
        }
        return true;
    }
};

I have a RxJava wrapper on sending this message.

If I just subscribe, everythig is fine. But if I do subscribe then unsubscribe the exception isn't caught and the app crashed. The RxJava wrapper doesn't do any work except sending the message in onSubscribe .

Any suggesions, how is it possible?

The stack trace:

08-01 10:02:58.422 13655-13655/com.mycompany.myapp E/AndroidRuntime: FATAL EXCEPTION: main
                                                                         Process: com.mycompany.myapp, PID: 13655
                                                                         com.mycompany.myapp.util.CustomException
                                                                             com.mycompany.myapp.util.LooperThread$1.handleMessage(LooperThread.java:33)
                                                                             at android.os.Handler.dispatchMessage(Handler.java:98)
                                                                             at android.os.Looper.loop(Looper.java:173)
                                                                             at com.mycompany.myapp.util.neulion.LooperThread.run(LooperThread.java:57)

Answer 1

I found a problem. After updating RxJava to the latest version (2.1.2) stack trace became more obvious. And I realized that even if exception is caught I call onError on my observable with my exception that I actually store in the catch block (the code isn't shown here).

08-03 10:53:25.811 6822-6822/com.mycompany.myapp E/AndroidRuntime: FATAL EXCEPTION: main
   Process: com.mycompany.myapp, PID: 6822
   io.reactivex.exceptions.UndeliverableException: java.lang.Exception: My exception
       at io.reactivex.plugins.RxJavaPlugins.onError(RxJavaPlugins.java:349)
       at io.reactivex.internal.operators.observable.ObservableCreate$CreateEmitter.onError(ObservableCreate.java:74)
       at com.mycompany.myapp.ui.screen.video.RxNeulion$1$1.onFailure(RxNeulion.java:29)
       at com.mycompany.myapp.util.neulion.Neulion$Callback.run(Neulion.java:59)
       at android.os.Handler.handleCallback(Handler.java:739)
       at android.os.Handler.dispatchMessage(Handler.java:95)
       at android.os.Looper.loop(Looper.java:148)
       at android.app.ActivityThread.main(ActivityThread.java:7303)
       at java.lang.reflect.Method.invoke(Native Method)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
    Caused by: java.lang.Exception: My exception
       at com.mycompany.myapp.util.neulion.MyHandlerCb.handleMessage(MyHandlerCb.java:27)
       at android.os.Handler.dispatchMessage(Handler.java:98)
       at android.os.Looper.loop(Looper.java:148)
       at com.mycompany.myapp.util.neulion.LooperThread.run(