Android Toast Messages not working

Question

I'm developing a game via Andengine for Android. I have MainActivity class and GameScene class. I use Toast messages in GameActivity. And it is working.

Toast.makeText(this, " Hello World", Toast.LENGTH_SHORT).show();

So I wanna use Toast messages in GameScene class. But it doesn't work. Here is the code:

Toast.makeText(activity, " Hello World", Toast.LENGTH_SHORT).show();

I have to use "activity" instead of "this". But it doesn't work

why?

EDITED:

when I use second one, an error occurs. LogCat: http://s29.postimg.org/k8faj9mdj/Capture.png

Answer 1

You're trying to display a Toast in a background thread. You should do all your UI operations on the main UI thread.

The exception RuntimeException: Can't create handler inside thread that has not called Looper.prepare() can be a little cryptic for beginners but essentially it tells you that you're in a wrong thread.

To solve it, wrap the toast to e.g. runOnUiThread():

activity.runOnUiThread(new Runnable() {
  @Override
  public void run() {
    Toast.makeText(...).show();
  }
});

Answer 2

There could be two reasons for your code to not work. It's ether your activity parameter is null or...

Short time after you showing the toast the activity is die, in that case it will kill the toast as well, to avoid this you can call activity.getApplicationContext() like in @Mehmet Seçkin answer.