android - Replacing Default Uncaught Exception Handler To Avoid Crash Dialog

Question

We wanted to replace the default uncaught exception so that the default crash dialog is not shown.

The problem was that if you call Thread.setDefaultUncaughtExceptionHandler(YourHandler) then in case of an exception the app "freezes" and you get an ANR (application not responding) dialog. We did experiment with System.exit() and Process.killProcess() which solved the issue but from reading on the matter it seemed that this is discouraged.

So how can it be done correctly?

Answer 1

TL;DR

Adopt the code in the framework's implementation of the default uncaught exception handler in com.android.internal.os.RuntimeInit.UncaughtHandler omitting the part that shows the dialog.

Drilldown

First it is clear that System.exit() and Process.killProcess() are mandatory in the scenario where the app is crashing (at least that's how the folks in Google think).
It is important to note that com.android.internal.os.RuntimeInit.UncaughtHandler may (and does) change between framework releases, also some code in it is not available for your own implementation.
If you are not concerned with default crash dialog and just want to add something to the default handler you should wrap the default handler. (see bottom for example)

Our Default Uncaught Exception Handler (sans dialog)

Thread.setDefaultUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
@Override
public void uncaughtException(Thread t, Throwable ex) {
    try {
        // Don't re-enter -- avoid infinite loops if crash-reporting crashes.
        if (mCrashing) {
            return;
        }
        mCrashing = true;

        String message = "FATAL EXCEPTION: " + t.getName() + "
" + "PID: " + Process.myPid();
        Log.e(TAG, message, ex);
    } catch (Throwable t2) {
        if (t2 instanceof DeadObjectException) {
            // System process is dead; ignore
        }
        else {
            try {
                Log.e(TAG, "Error reporting crash", t2);
            } catch (Throwable t3) {
                // Even Log.e() fails!  Oh well.
            }
        }
    } finally {
        // Try everything to make sure this process goes away.
        Process.killProcess(Process.myPid());
        System.exit(10);
    }
}

})

Wrapping the default handler

final Thread.UncaughtExceptionHandler defHandler = Thread.getDefaultUncaughtExceptionHandler();
Thread.setDefaultUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
    @Override
    public void uncaughtException(Thread t, Throwable ex) {
        try {
            //your own addition 
        } 
        finally {
            defHandler.uncaughtException(t, ex);
        }
    }
});