Question

I am new to android development. I would like to accomplish a task described as follows:

• A main activty which calls external class(the other class would extend AsyncTask) to parse xml and receive json by requesting to web service and starts a ProgressDialog.
• The class performs xml and json parsing in its doInBackground method.
• In the onPostExecute method after parsing is complete, dismiss the ProgressDialog that was set in the main activity.
• I could do this by passing the ProgressDialog object to the parsing class and dismissing the same object in its onPostExecute method.

I think passing an instance of UI object as argument is not a good approach to program, I hope there must be some other ways to work around.

Please suggest.
Thank you

Answer 1

The easiest way to decouple these is to use an interface:

1. Define a call-back interface (let’s call it WorkDoneListener) with a single method: workDone().
2. Declare your activity class to implement WorkDoneListener and implement workDone() to dismiss the dialog.
3. Define the AsyncTask’s constructor to accept a WorkDoneListener. Stash the reference in a member field.
4. In onPostExecute, call the listener’s workDone() method.