Interface Vs anonymous class in android

Question

I am little bit confused regarding backend working of anonymous class, like if we have a button and we are setting onclickListener

Button B = (Button)findViewById(R.id.myButton);
B.setOnClickListener(new onClickListener(){ 
          public void onClick(View V){ 
              Log.v("","Hello world");
          }
 ));

What is here actually happening in backend ?Does this will implement interface of View.OnClickListener or something else???

Please look over this http://stackoverflow.com/questions/5848510/how-can-an-anonymous-class-to-extends-or-implements — Dheeresh Singh, May 26 '12 at 18:22

score 2 · Answer 1 · edited May 23 '17 at 12:27

2

Please look over this

How can an anonymous class use "extends" or "implements"?

http://docstore.mik.ua/orelly/java-ent/jnut/ch03_12.htm

edited May 23 '17 at 12:27

Community

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answered May 26 '12 at 18:23

Dheeresh Singh

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score 2 · Answer 2 · answered May 26 '12 at 18:24

2

Yes it is an instance of new unnamed class that implements the OnClickListener interface.

answered May 26 '12 at 18:24

ditkin

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Alex Lockwood · Accepted Answer · 2012-05-26T18:34:59.237

1

Anonymous classes must always extend a class or implement an interface.

b.setOnClickListener(new OnClickListener() { 
    public void onClick(View V) { 
        Log.v("", "Hello world");
    }
});

In this case, you are creating a new anonymous (unnamed) class that implements the View.OnClickListener interface. This works because the setOnClickListener method takes an argument of type View.OnClickListener.

edited May 26 '12 at 18:34

answered May 26 '12 at 18:29

Alex Lockwood

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There is simple typo here that could be confusing. There is no onClickListener Interface. It is OnClickListener. – ditkin May 26 '12 at 18:32

Interface Vs anonymous class in android

3 Answers3