Android Programming for Beginners

OOP and inheritance

We have seen how we can use other people's hard work by instantiating/creating objects from the classes of an API like Android. But this whole OOP thing goes even further than that.

What if there is a class that has loads of useful functionality in it but is not quite what we want? We can inherit from the class and then further refine or add to how it works and what it does.

You might be surprised to hear that we have done this already. In fact, we have done this with every single app we have created. When we use the extends keyword, we are inheriting. Remember this?

public class MainActivity extends AppCompatActivity ...

Here, we are inheriting the AppCompatActivity class along with all its functionality—or more specifically, ...