Question

cancel(getIntent().getExtras().getInt(“notificationID”));

why we use of dot operator in between these methods? as cancel(int) method takes only one integer parameter.it has 3 methods as parametr…..what exactly the code will do..?

Answer 1

You should try going through the concepts of object oriented programming first.

To answer your question, getIntent() returns an object of type intent. We call the getExtras() on the Intent object which returns an object of type Bundle. Then we call getInt() on the Bundle object to finally get the int we want to pass to the cancel() method.

The statement is equivalent to :

Intent i = getIntent();
Bundle b = i.getExtras();
int id = b.getInt("notificationID");
cancel(id);

If we don’t need any of the intermediate objects, we can write the whole thing in a single line.

Hope that helps.