How to know that a thread is finished

Question

I have an activity in which i am running a thread to hit the web service.i want to finish the activity only when the thread is finished.

why don't you simply finish your activity as the last statement in the Thread which obviously gets executed only at the last. — Andro Selva, Aug 07 '12 at 08:52
@Andro Selva I tried but the activity is finished first and the thread is running in the background — swati, Aug 07 '12 at 08:57

score 7 · Answer 1 · answered Aug 07 '12 at 09:06

To make your life easier use Android AsyncTask Object. This provides the same background process as a Thread but handles everything for you. This includes callbacks at different stages of the AsyncTask. This includes once it has finished doing what you ask of it in the background via the onPostExecute() function.

From the documentation:

private class DownloadFilesTask extends AsyncTask<URL, Integer, Long> {
 protected Long doInBackground(URL... urls) {
     int count = urls.length;
     long totalSize = 0;
     for (int i = 0; i < count; i++) {
         totalSize += Downloader.downloadFile(urls[i]);
         publishProgress((int) ((i / (float) count) * 100));
         // Escape early if cancel() is called
         if (isCancelled()) break;
     }
     return totalSize;
 }

 protected void onProgressUpdate(Integer... progress) {
     setProgressPercent(progress[0]);
 }

 protected void onPostExecute(Long result) {
     showDialog("Downloaded " + result + " bytes");
 }
}

`ASyncTask` are good but the question is about knowing when a thread finishes, which is possible so no need to find a workaround. — shkschneider, Aug 07 '12 at 09:08
@shkschneider - onPostExecute happens at the end of the Async thread. So, nothing prevents you from notifying the main thread that the thread has finished in there. — Eugene Kartoyev, Aug 18 '20 at 20:43

score 4 · Accepted Answer · answered Aug 07 '12 at 08:53

4

You can use Thread.join(), which works for all Java programs (not just Android).

answered Aug 07 '12 at 08:53

Laurent Perrin

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I you still want to use threads over ASyncTask, then this is the way to go. Otherwise follow Richard's answer. – shkschneider Aug 07 '12 at 09:10

score 0 · Answer 3 · answered Aug 07 '12 at 08:58

0

You can call isAlive() method of your Thread or getStatus() if you use AsyncTask

answered Aug 07 '12 at 08:58

Saasha

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This will returns if the thread is alive, not trigger something when it finished. A loop is not the way to go. – shkschneider Aug 07 '12 at 09:09

How to know that a thread is finished

3 Answers3