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exception handling – how to implement uncaughtException android

Posted by: admin April 23, 2020 Leave a comment

Questions:

I found this
Android: How to auto-restart application after it's been "force closed"?

but I don’t know where and how to put the alarm manager

thanks

How to&Answers:

You can catch all uncaught exceptions in your Application extension class. In the exception handler do something about exception and try to set up AlarmManager to restart your app. Here is example how I do it in my app, but I only log exception to a db.

public class MyApplication extends Application {
    // uncaught exception handler variable
    private UncaughtExceptionHandler defaultUEH;

    // handler listener
    private Thread.UncaughtExceptionHandler _unCaughtExceptionHandler =
        new Thread.UncaughtExceptionHandler() {
            @Override
            public void uncaughtException(Thread thread, Throwable ex) {

                // here I do logging of exception to a db
                PendingIntent myActivity = PendingIntent.getActivity(getContext(),
                    192837, new Intent(getContext(), MyActivity.class),
                    PendingIntent.FLAG_ONE_SHOT);

                AlarmManager alarmManager;
                alarmManager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
                alarmManager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, 
                    15000, myActivity );
                System.exit(2);

                // re-throw critical exception further to the os (important)
                defaultUEH.uncaughtException(thread, ex);
            }
        };

    public MyApplication() {
        defaultUEH = Thread.getDefaultUncaughtExceptionHandler();

        // setup handler for uncaught exception 
        Thread.setDefaultUncaughtExceptionHandler(_unCaughtExceptionHandler);
    }
}

Answer:

Basically, you have to implement your own instance of an UncaughtExceptionHandler, then you will have to make sure that for every thread your App runs you call setUncaughtExceptionHandler.

Then, when an uncaught exception occurs in any of those threads, your own UncaughtExceptionHandler will be called and you can from there schedule your App’s restart or whatever before passing on the exception.

I don’t know if it really makes sense to just restart the App in that case, though. The user may be quite “surprised” if, in the middle of his interaction, the App ‘resets’ and does not resume where it was just a second ago, possibly even losing the user’s previous input, etc..

Edit:

See here, the answer of Gyuri. Apart from that you only need to implement an interface, namely UncaughtExceptionHandler, and ‘paste’ Gyuri’s code into that.

Edit #2:

For reference: A service started “sticky” might achieve the desired result, too.