Toasts
as well as other components that manipulates the user interface must not be used outside of the UI thread.
What you could do in order to solve your issue, is to design a messaging system between the thread managing you game, and your UI thread. In order to do so, you can use a Handler
and its messaging facilities (sendMessage
, post
, postDelayed
...) to send messages or even Runnables
to be run on your main thread.
If you create a Handler
in the main thread, it will automatically associate itself with your main thread's event loop, thus making every work sent to it be executed in the main thread.
A basic example of what you could do would be :
class MainActivity extends Activity {
// The handler is associated with your Activity's thread
private Handler _handler = new Handler();
// ...
private Thread _worker = new Thread() {
@Override
public void run() {
_handler.post(new Runnable() {
@Override
public void run() {
Toast.makeText(MainActivity.this, "Some text", Toast.LENGTH_SHORT).show();
}
});
}
};
};
As a shorthand, you could also use Activity.runOnUiThread(Runnable r)
that executes the given runnable in the UI thread by default.