title: How to turn off an app with a button in android
body: <p>i try to implement a way to turn off an app with a button. If i push the button, the app seems to being closed, but if i look which applications a currently running, my app is still active. 
  Here ist my code:</p>
  
  <pre><code>turnOffApp.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View v) {
              finishAffinity();
              System.exit(0);
          }
      });
  </code></pre>