How to throw exception from AsyncTask and handle it outside

Question

During my implantation I need to throw several exceptions from a class, and handle them outside. Inside the class I made, I also implemented AsyncTask private class, and from this class , as well, I need to throw the exceptions. I realized that I cannot throw any exception from AsyncTask class, but only to handle it. This is not what I need.

Is there some kind of solution, so I'll be able to throw any exception I want from inside the AsyncTask?

or could return a object with the information you need. e.g. `String result; String error;` or sth like this. — A.S., May 12 '14 at 09:12
@SainathPatwarykarnate Can you please explain how to use listener here? — YGT, May 12 '14 at 09:26
@A.S. the only problem is that if I'll return an object, I'll need to wait for the task to end, and I'll loose the asynchronous of the AsyncTask. I do need it to run in the background. — YGT, May 12 '14 at 09:28
check the ans http://stackoverflow.com/a/23534743/2751529 which is used to pass the result same way you can pass the Exception object as a result hope it helps — Sainath Patwary karnate, May 12 '14 at 09:38

score 2 · Answer 1 · answered May 12 '14 at 09:51

I do something like below.
- Write your own implementation of MyListener class.Pass it in the constructor of MyAsyncTask class.
- Check the return value of doInBackground method,and call relevant method.

public interface MyListener {
    public void onSuccess();
    public abstract void onFail();
}

public class MyAsyncTask extends AsyncTask<String, Void, String>{  
    private MyListener listener;  
    public MyAsyncTask(MyListener listener){
        this.listener = listener;
}

    protected String doInBackground(String... params) {
        return aValue;
    }

    protected void onPostExecute(String aValue) {
        //Check aValue,if OK
        listener.onSuccess();
        //else
        listener.onFail();
    }
}

How to throw exception from AsyncTask and handle it outside

1 Answers1