title: Finish() or moveTaskToBack() doesn't work
body: <p>I'm trying to put an activity in the background or simply kill it. I'm creating the activity inside a runnable, because I need to wait 2 seconds before it opens:</p>
  
  <pre><code>case TelephonyManager.CALL_STATE_RINGING:
              long user_logged = AppSettings.getLoggedUserSQLiteID(context);
              if (user_logged != 0) {
                  final Handler h = new Handler();
                  Runnable r1 = new Runnable() {
                      @Override
                      public void run() {
                          String phoneNr = inte.getStringExtra("incoming_number");
                          Intent phonecall = new Intent(ctx, PhoneCall.class);
                          phonecall.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                          phonecall.putExtra("phone_number", phoneNr);
                          ctx.startActivity(phonecall);
                      }
                  };
                  h.postDelayed(r1, 2000); // 1 second delay
              }
  break;
  </code></pre>
  
  <p>In the button I specify the method to run on click, like <code>android:onClick="acceptCall"</code>:</p>
  
  <pre><code>public void acceptCall(View v) {
  
      try {
          Runtime.getRuntime().exec("input keyevent " + Integer.toString(KeyEvent.KEYCODE_HEADSETHOOK));
      } catch (IOException e) {
          // Runtime.exec(String) had an I/O problem, try to fall back
          String enforcedPerm = "android.permission.CALL_PRIVILEGED";
          Intent btnDown = new Intent(Intent.ACTION_MEDIA_BUTTON).putExtra(
                  Intent.EXTRA_KEY_EVENT, new KeyEvent(KeyEvent.ACTION_DOWN,
                          KeyEvent.KEYCODE_HEADSETHOOK));
          Intent btnUp = new Intent(Intent.ACTION_MEDIA_BUTTON).putExtra(
                  Intent.EXTRA_KEY_EVENT, new KeyEvent(KeyEvent.ACTION_UP,
                          KeyEvent.KEYCODE_HEADSETHOOK));
  
          this.sendOrderedBroadcast(btnDown, enforcedPerm);
          this.sendOrderedBroadcast(btnUp, enforcedPerm);
  
          super.finish();
  
      }
  }
  </code></pre>
  
  <p>To finish, or put it in the background, I tried these lines of code:</p>
  
  <pre><code>super.finish();
  super.moveTaskToBack(true);
  this.finish();
  this.moveTaskToBack(true);
  </code></pre>
  
  <p>However, none of them seems to work for me. Can anyone help me understand why? </p>