Crashlytics in Android - how to capture all exceptions/crashes in one place

Question

Using Java (android but this is a java question ) i have created a default exception handler in the application class like this more or less which was taken from some SO thread:

    public class MyApplication extends Application {
@Override
    public void onCreate() {
        super.onCreate();
        AppInitialization();
    }

    private void AppInitialization() {
         defaultUEH = Thread.getDefaultUncaughtExceptionHandler();
         Thread.setDefaultUncaughtExceptionHandler(_unCaughtExceptionHandler);
    }

    private UncaughtExceptionHandler defaultUEH;

    // handler listener
    private Thread.UncaughtExceptionHandler _unCaughtExceptionHandler = new Thread.UncaughtExceptionHandler() {
        @Override
        public void uncaughtException(Thread thread, Throwable ex) {
            ex.printStackTrace();
            // TODO handle exception here
        }
    };
}

Lets talk about what my goal is. I need to record extra information for crashLytics crash reports. so anytime a exception occurs the hook uncaughtException(Thread thread, Throwable ex) will be called. i assume that will work for crashes and exceptions (not sure).

3 questions on this:

1. will this affect how crashLytics works since im overrding the default exception handler.

2. Will this allow the app to continue - i dont want this. i only want to log the exception somewhere else and have it continue as if the defaultexceptionHandler did not exist. Otherwise, QA regression will have a hard time seeing the bugs so we can fix them. If i call defaultUEH.uncaughtException(thread, ex) from within uncaughtException(thread,ex) will it keep looping ?

3. What thread is associated with setDefaultUncaughtExceptionHandler ? does this work for all threads for example or just main thread ?

So to be clear, i need a way to send additional information on every crashlytics crash/exception. How ?

UPDATE: I see here that someone found a solution but using this method does it make crashlytics report the fatal issues as well ?

Answer 1

i found a way to do this cleanly and it tests ok. be careful with Crashlytics.log to send logs during a crash report. seems to not work consistently on version Crashlytics 2.3.14.151. I use Crashlytics.setString(key, value) instead. crashlytics.log seems to work fine with crashlytics.logException(..) though.

the other question i had was would it work on asychrnous exceptions. The answer is yes i tested it myself.

so it catches all exceptions from all threads.

The rest of the idea is similar to here. The person is using a decorator pattern over the defaultExceptionHandler to add functionality to the uncaughtException method.

this is how i enhanced it:

   public class DefaultUnCaughtExceptionHandlerDecorator implements UncaughtExceptionHandler {

   private UncaughtExceptionHandler mDefaultUncaughtExceptionHandler; //we will decorate the default handler to add functionality to it

   public DefaultUnCaughtExceptionHandlerDecorator(UncaughtExceptionHandler mDefaultUncaughtExceptionHandler) {
       this.mDefaultUncaughtExceptionHandler = mDefaultUncaughtExceptionHandler;
   }

   @Override
   public void uncaughtException(Thread t, Throwable e) {

       logToCrashLytics(); //add our crashlytics logging and keys here
       //  we have added our crashlytics extra data, now invoke Crashlytics
       mDefaultUncaughtExceptionHandler.uncaughtException(t, e);
   }

   private void logToCrashLytics() {

           Crashlytics.setUserIdentifier(Model.getUserID());//or whatever. this will show directly on crashlytics dashboard a pretty element

       Crashlytics.setString("Some useful Info","user is logged in"); // or whatever you want, such as printing out singleton managers references or model info
     //dont use Crashlytics.Log(..) here. it wont work consistent. 
   }

}

now in your subclass of Application class AFTER crashlytics is installed do this:

Thread.setDefaultUncaughtExceptionHandler(new DefaultUnCaughtExceptionHandlerDecorator(Thread.getDefaultUncaughtExceptionHandler()));