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Android Android Lists and Adapters (2015) Acting on List Item Taps Using a ListView in a Regular Activity

J A
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J A
Full Stack JavaScript Techdegree Student 4,646 Points
Posted by J A
.a{fill-rule:evenodd;}techdegree
J A
Full Stack JavaScript Techdegree Student 4,646 Points

Why is there a question mark for the type of the AdapterView in the listener?

Does the question mark have a special meaning in the following method signature for the onItemClick() function?

            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
               // Code for Toast message here
            }

1 Answer

Varun Singh
Varun Singh
1,905 Points
Varun Singh
Varun Singh
1,905 Points

In AdapterView<?> question mark stands for " Wild card " to relax the restriction on variable. Also, it comes under generics Refer:-http://docs.oracle.com/javase/tutorial/java/generics/upperBounded.html

For AdapterVIew: https://developer.android.com/reference/android/widget/AdapterView.html

For AdapterView.OnItemClickListener: https://developer.android.com/reference/android/widget/AdapterView.OnItemClickListener.html