Is there a way to get Async Task to return data, or be able to send a param with a method to call after

Question

I have an async task class that acts as a wrapper for http requests. I want to be able to either return the data from onPostExecute or somehow specify a method to send that data to after. I can't just call the function explicately because different responses have to go to different methods. Maybe if theres something like a call_user_function from php.

 private class Get extends AsyncTask<Void, Void, ContainerData> {

    @Override
    protected void onPreExecute() {
        if (pbTitle != null) {
            pbTitle.setVisibility(View.VISIBLE);
        }
        if (preText != null) {
            tvUpdate.setText(preText);
            tvUpdate.setVisibility(View.VISIBLE);
        }
    }

    @Override
    protected void onProgressUpdate(Void... progress) {

    }

            //this line will not work, the return type wants to be void
    @Override
    protected ContainerData onPostExecute(ContainerData obj) {
        if (pbTitle != null) {
            pbTitle.setVisibility(View.GONE);
        }
        if (preText != null) {
            tvUpdate.setText("");
            tvUpdate.setVisibility(View.GONE);
        }
        updateResponse(obj);

        return obj;

    }

    @Override
    protected ContainerData doInBackground(Void... params) {

        ContainerData obj = null;

        RestClient client = new RestClient(context);

        for (Param param : methodParams) {

            client.AddParam(param.getKey(), param.getValue());
        }

        client.setMethod(method);

        try {
            client.Execute();
        } catch (Exception e) {
            e.printStackTrace();
        }

        obj = client.getResponseObject();

        return obj;
    }

    public String updateResponse(ContainerData responseObject) {


        try {
            // throws API exception
            responseObject.checkSuccess();

            String message = responseObject.getMessage();

            if (message != null) {
                Toast.makeText(context, message, Toast.LENGTH_SHORT).show();
            }

            dataString = responseObject.getDataString();

        } catch (ApiException e) {
            Toast.makeText(context, e.getMessage(), Toast.LENGTH_SHORT).show();
        } catch (Exception e) {
            e.printStackTrace();
        }

        return dataString;

    }
}

Answer 1

You could define an ICommand interface:

public interface ICommand
{
    void execute();
}

And create a new attribute to the Get class

private ICommand command;
public void setCommand(ICommand command)
{
      this.command = command
}

Finally when you create the instance, set the command like this:

setCommand(new ICommand() {

        @Override
        public void execute() {
            // Your specific code 
        }
    });

Of course, if you need the ContainerData response data, you can modify ICommand interface so the execute receive the ContainerData instance.

Hope it help! :)

Answer 2

You've mixed up the ordering in line:

private class Get extends AsyncTask<Void, Void, ContainerData>

The return type goes first. You should have:

private class Get extends AsyncTask<ContainerData, Void, Void>

Answer 3

Use Handler. And on post execute send different messages to handler for different response. From the handler you can call different methods.