Android ListAdapter，ArrayAdapter

Question

I want to know what is a ListAdapter and ArrayAdapter ? Also, I am so confused about the fact that I can set a type ListAdapter to be constructed using ArrayAdapter as shown below.

ListAdapter theAdapter = new ArrayAdapter<String>()

How can this be? How can a ListAdapter be constructed using the constructor of an ArrayAdapter ?

Answer 1

ListAdapter is an interface,see here .

BaseAdapter is an class implemented ListAdapter interface,see here .

And ArrayAdapter is subclass of BaseAdapter ,see here ;

So we can write a code like this:

ListAdapter theAdapter = new ArrayAdapter();

Just like

View.OnClickListener listener = new A();//A implements OnClickListener interface