Let say we have an Activity that wants to receive a messages from AsyncTask.
We create an Interface AsyncResponse
public interface AsyncResponse {
void publishLog(String logContent);
}
We create our AsyncTask:
public class FileReaderTask
extends AsyncTask < Void, Void, List < AbstractX > > {
// delegate should be set in the Activity
public AsyncResponse delegate = null;
String xyz = "";
// ...
@Overrideprotected void onPreExecute() {
delegate.publishLog(xyz);
}
@Overrideprotected void onPostExecute(List x) {
...
delegate.publishLog(xyz);
}
}
Now we can tie together the AsyncTask and Activity:
public class FileReaderActivity extends Activity implements AsyncResponse {
private static final String TAG = FileReaderActivity.class.getCanonicalName();
FileReaderTask asyncTask = new FileReaderTask();
private TextView logText;
/** * Called when the activity is first created. */
@Override public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
logText = (TextView) findViewById(R.id.logText);
// tell Async Task that this Activity will listen
asyncTask.delegate = this;
asyncTask.execute();
}
/** * This method will receive log from Async Task. * @param logContent */
@Override public void publishLog(String logContent) {
logText.append(logContent);
}
}
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