onCreate() method

• Operating system calls onCreate() method (in c language, main() is called).
•  

syntax:

public class MainActivity extends android.app.Activity
{
 @override
public void onCreate(Bundle savedInstanceState)
{
  //call the super class method
  super.onCreate(savedInstanceState);
 //specify the xml file
setContentView(R.layout.activity_main);
}//end of onCreate()
}

Q: What is Bundle? 

Ans: Bundle is a predefined class, it specifies the state of the activity.

Q: What is  savedInstanceState?

Ans: It is just varialbe (reference), we can give any name instead of savedInstanceState