Android Respond to Button Click Events

public void buttonShow_onClick(View view)
    {
        Toast toast=Toast.makeText(this,"Hello",Toast.LENGTH_LONG);
        toast.show();
    }

References
https://www.youtube.com/watch?v=6vixsiBlEOs&list=PLshdtb5UWjSp0879mLeCsDQN6L73XBZTk&index=10
https://github.com/mhdr/AndroidSamples/tree/master/005
https://developer.android.com/guide/topics/ui/notifiers/toasts.html