ক্যাগায়ে কালানের সমাধানের আরও বিস্তৃত সমাধান নীচে দেখানো হয়েছে:
AsyncTaskResult
public class AsyncTaskResult<T>
{
private T result;
private Exception error;
public T getResult()
{
return result;
}
public Exception getError()
{
return error;
}
public AsyncTaskResult(T result)
{
super();
this.result = result;
}
public AsyncTaskResult(Exception error) {
super();
this.error = error;
}
}
ExceptionHandlingAsyncTask
public abstract class ExceptionHandlingAsyncTask<Params, Progress, Result> extends AsyncTask<Params, Progress, AsyncTaskResult<Result>>
{
private Context context;
public ExceptionHandlingAsyncTask(Context context)
{
this.context = context;
}
public Context getContext()
{
return context;
}
@Override
protected AsyncTaskResult<Result> doInBackground(Params... params)
{
try
{
return new AsyncTaskResult<Result>(doInBackground2(params));
}
catch (Exception e)
{
return new AsyncTaskResult<Result>(e);
}
}
@Override
protected void onPostExecute(AsyncTaskResult<Result> result)
{
if (result.getError() != null)
{
onPostException(result.getError());
}
else
{
onPostExecute2(result.getResult());
}
super.onPostExecute(result);
}
protected abstract Result doInBackground2(Params... params);
protected abstract void onPostExecute2(Result result);
protected void onPostException(Exception exception)
{
new AlertDialog.Builder(context).setTitle(R.string.dialog_title_generic_error).setMessage(exception.getMessage())
.setIcon(android.R.drawable.ic_dialog_alert).setPositiveButton(R.string.alert_dialog_ok, new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int which)
{
//Nothing to do
}
}).show();
}
}
উদাহরণ টাস্ক
public class ExampleTask extends ExceptionHandlingAsyncTask<String, Void, Result>
{
private ProgressDialog dialog;
public ExampleTask(Context ctx)
{
super(ctx);
dialog = new ProgressDialog(ctx);
}
@Override
protected void onPreExecute()
{
dialog.setMessage(getResources().getString(R.string.dialog_logging_in));
dialog.show();
}
@Override
protected Result doInBackground2(String... params)
{
return new Result();
}
@Override
protected void onPostExecute2(Result result)
{
if (dialog.isShowing())
dialog.dismiss();
//handle result
}
@Override
protected void onPostException(Exception exception)
{
if (dialog.isShowing())
dialog.dismiss();
super.onPostException(exception);
}
}