Trigger event when AsyncTask is complete using Listener

Question

I'm having some confusion on how to use Listeners to pass information between classes and activities. The scenario is this: I have a task that reads data from an Sqlite database and puts this data into an ArrayList that is passed to an Adapter which then displays it on the screen. The question: My app crashes when i attempt to update the listener interface with a value. It doesnt show anything in the logcat...it just hangs the app. Could someone kindly point out where i'm going wrong. - Thanks Details: I have the database processing done by a class called DatbaseRoutines and within it an inner method doing the heavy lifting. the method is using AsyncTask so as not to hog the main thread. I have created and Interface with a single method ``` public interface DatabaseProcessListener { public void ProcessingIsDone(boolean blnProcessIsFinished); } ``` In my DatabaseRoutines class i am creating a private variable ``` private DatabaseProcessListener dbProcesslistener; ``` along with a sette…

Accepted Answer

Got the Answer! I was not initializing the listener in my calling class. all i needed to do was put in this line

```
db.setDbProcesslistener(this);
```

ie

```
DatabaseRoutines db = new DatabaseRoutines(MyActivity.this);
db.setDbProcesslistener(MyActivity.this);
```

and it started working.

Thanks to everyone who had a look and tried to think of the solution :)

Trigger event when AsyncTask is complete using Listener

Solution

Problem