How do I run an AsyncTask over and over?

Question

I have an onCreate method that runs the code below. In a nutshell the code retrieves data from the server and shows it on the screen for a messaging program. It only does it once, but I would like it to run the AsyncTask every 3 seconds (to try to simulate a chat). I'm pretty sure this is not the way to go about having a chat system but, I just need something that works for now (as a proof of concept) and I'll focus on the correct way of implementing it later.

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.chat_box);// sd

        final Functions function = new Functions();
        final SharedPreferences prefs = PreferenceManager
                .getDefaultSharedPreferences(getBaseContext());
        whatroom = prefs.getString("chat", "null");

        new AsyncTask<String, Void, String>() {
            @Override
            protected String doInBackground(String... args) {
                return function.getInbox(args[0]);
            }

            @Override
            protected void onPostExecute(String result) {
                TextView inbox = (TextView) findViewById(R.id.inbox);
                ProgressBar progressBar = (ProgressBar) findViewById(R.id.progressBar1);
                progressBar.setVisibility(View.GONE);
                inbox.setText(result);
            }

        }.execute(whatroom);
    }

I've tried putting a simple while statement around the asynctask but, it just force closes.

We usually don't use AsyncTask for periodical task, check out my answer [here](http://stackoverflow.com/questions/8098806/where-do-i-create-and-use-scheduledthreadpoolexecutor-timertask-or-handler/8102488#8102488) to see if it helps. — yorkw, Apr 25 '12 at 23:22
Yorkw, your answer in that question was perfect. It worked for me and did everything I needed it to do. — EGHDK, Apr 26 '12 at 03:19

score 2 · Accepted Answer · answered Apr 25 '12 at 23:11

2

You cannot reuse an AsyncTask instance. You would need to create fresh instances each pass of your loop.

answered Apr 25 '12 at 23:11

CommonsWare

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Should I bother trying to create a fresh instance, or should I go another route (like loaders mentioned by @Steve)? – EGHDK Apr 25 '12 at 23:22
@EGHDK: This does not feel like a `Loader` scenario to me. You might use `Timer` and `TimerTask`, plus `post()` on your `TextView` to get those updates to occur on the main application thread instead of the task's thread. – CommonsWare Apr 25 '12 at 23:27
So if anyone finds this in the future. CommonsWare gave the answer to the question but, yorkw gave me the solution. Thanks all for your time. I appreciate it. – EGHDK Apr 27 '12 at 04:24

score 0 · Answer 2 · answered Apr 25 '12 at 23:07

Without additional information, it's difficult to give you a specific answer. However look into abstracting everything using a Loader, using a Service, etc

Regarding Loaders:

They are available to every Activity and Fragment.

They provide asynchronous loading of data.

They monitor the source of their data and deliver new results when the content changes.

They automatically reconnect to the last loader's cursor when being recreated after a configuration change. Thus, they don't need to re-query their data.

The asyncTask simply runs the function `getInbox()`, which gets information from the web using a php script. Would a loader be the right thing to use for this? — EGHDK, Apr 25 '12 at 23:10

How do I run an AsyncTask over and over?

2 Answers2