Android Button or Imagebutton click Event using set OnClickListener Method

public class Aboutus extends Activity {
private ImageButton back;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        back=(ImageButton)findViewById(R.id.header_left_btn);
        back.setOnClickListener(new OnClickListener(){

public void onClick(View arg0) {
// TODO Auto-generated method stub
finish();
}
       
        });
}
}