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POAndroid: TimerTask scheduled for repetition getting fired only once
 

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  1. POAndroid: TimerTask scheduled for repetition getting fired only once
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    <p>Ok this is a very weird problem I am having, and I'm pretty sure that I am messing up somewhere, but I can't quite figure out where.</p> <p>What I am trying is - </p> <ul> <li>Schedule a <code>Timer</code> to execute a <code>TimerTask</code> every five seconds</li> <li>The <code>TimerTask</code> in turn executes an <code>AsyncTask</code> (which in this case simple sleeps for a second before returning the static count of the number of AsyncTasks).</li> <li>Finally, the aforementioned count is updated in the UI.</li> </ul> <p>And of course, the appropriate <code>Handler</code>s and <code>Runnable</code>s have been used to post asynchronous messages from other threads to the UI.</p> <p>This code executes only once. I expect it to fire every 5 seconds. Here's the code. </p> <p><em><strong>Note:</em></strong> I had no idea what to do with the <code>Looper</code>. I put it there after trial and error!</p> <pre><code>public class TimerAsyncMixActivity extends Activity { public static final String TAG = "TimerAsyncMix"; static int executionCount = 0; Handler mHandler = new Handler(); @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); new Timer().schedule(new MyTimerTask(this), 0, 5000); } class MyAsyncTask extends AsyncTask&lt;String, Void, Integer&gt;{ @Override protected Integer doInBackground(String... params) { try { Thread.sleep(1000); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } return ++executionCount; } @Override protected void onPostExecute(Integer result) { mHandler.post(new UpdateUiThread(TimerAsyncMixActivity.this, result)); super.onPostExecute(result); } } } class MyTimerTask extends TimerTask{ private TimerAsyncMixActivity tma; public MyTimerTask(TimerAsyncMixActivity tma) { this.tma = tma; } @Override public void run() { Looper.prepare(); Log.d(TimerAsyncMixActivity.TAG, "Timer task fired"); tma.new MyAsyncTask().execute(); Looper.loop(); Looper.myLooper().quit(); } } class UpdateUiThread implements Runnable{ int displayCount; TimerAsyncMixActivity tma; public UpdateUiThread(TimerAsyncMixActivity tma, int i) { this.displayCount = i; this.tma = tma; } @Override public void run() { TextView tv = (TextView) tma.findViewById(R.id.tvDisplay); tv.setText("Execution count is : "+displayCount); } </code></pre> <p>Can anyone point me to what I'm doing wrong?</p>
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    1. COI checked the code a few times and I can't see anything wrong. Do you get any on logcat? As a side note, you could simplify this a lot by just running the AsyncTask (there is no need for the extra 2 threads).
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    2. CO@Augusto, I was getting some errors which prompted me to put those Looper-related statements in there. Well, this code is just a skeleton of my actual app. My intention is to fetch information using REST and update the UI (I use AsyncTask for this); and to do this every N seconds (I use TimerTask for this). I tried [this approach] (http://stackoverflow.com/questions/6534824/android-implication-of-using-asynctask-to-make-repeated-ajax-calls) - but it is fraught with OutOfMemory issues. Is there a better way to achieve this?
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