What is the AdapterView<?> means in the OnitemClick() Method?What is the use of other parameters in it?

Question

gridview.setOnItemClickListener(new OnItemClickListener() {
        public void onItemClick(AdapterView parent, View v, int position, long id) {
            Toast.makeText(HelloGridView.this, "" + position, Toast.LENGTH_SHORT).show();
        }
    });

Answer 1

The ? means that the datatype is unknown and it can be any type.

Answer 2

The <?> indicates a Generic. Read more at http://java.sun.com/docs/books/tutorial/java/generics/index.html

For a description of all the parameters, refer to http://developer.android.com/reference/android/widget/AdapterView.OnItemClickListener.html