Activity is the base class for the visul, interactive components of your application
It is roughly equivalent to a Form in traditional desktop development.
The following snippet shows the skeleton code for an Activity-based class
note that it extends Activity, overriding the onCreate method.
import android.app.Activity;
import android.os.Bundle;
public class HelloWorld extends Activity{
public void onCreate(Bundle b)
{
super.onCreate(b)
}
}