title: Best practice to create a thread that runs every hour in Android?
body: <p>So I'm attempting to create background task that needs to be run every hour in an Android app. Its a rather heavy task that takes around 5 - 10 minutes to finish, and right now it runs on the UI thread which of course isn't good, because it hangs the whole application. I've attempted the following in my MainActivity onCreate:</p>
  
  <pre><code>new Thread(new Runnable() {
  
      private Handler HeavyTaskHandler = new Handler(Looper.getMainLooper());
  
      public void run(){
          final TextView updatedTxt = findViewById(R.id.txt);
          updatedTxt.post(new Runnable() {
              @Override
              public void run() {
                  updatedTxt.setText("Performing cleanup..");
              }
          });
  
          HeavyTask(); // &lt;-- This method runs for 5 - 10 minutes
  
          updatedTxt.post(new Runnable() {
              @Override
              public void run() {
                  updatedTxt.setText("Done..");
              }
          });
  
          HeavyTaskHandler.postDelayed(this, HeavyTaskCycle);
      }
  }).start();
  </code></pre>
  
  <p>I have two issues with the above</p>
  
  <ul>
  <li>It works fine the first time, and the task is performed in the background well without hanging the UI thread. However, after this first time and the next time(s) it is run, the UI thread hangs again when it is run. What am I missing?</li>
  <li>Notice that before the HeavyTask() method is called i try to set a TextViews text to "Performing cleanup.." .. This never shows, only the "Done.." which happens after the HeavyTask() method is done. How can i ensure that the message also appears before?</li>
  </ul>