How to Know That a Thread Is Finished [Duplicate]

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");
 }
}

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