How to handle visibility changes for a custom android view/widget

Question

I have written a custom view in android. I need to do some processing when visibility of this view is changed. Is there some listener which is called when visibility of a view/widget is changed ?

Edit:

I know how to change the visibility, would like to know if there is a listener which is called when we setVisibility on the view!

Answer 1

Do you want to do that processing within your custom view class? If so, then why not just override the setVisibility() method, call super(), and then do your custom processing?

Answer 2

I know how to change the visibility, would like to know if there is a listener which is called when we setVisibility on the view!

you have to subclass your view/widget and override setVisibility, and register a interface on which you will recive the notification. For instance:

public class MyView extends View {

  public interface MyListener {
    public void onSetVisibilityCalled();
  }

  public void registerListener(MyListener myListener) {
    this.mListener = myListener;
  }

 public void setVisibility (int visibility) {
   super.setVisibility(visibility);
   if (mListener != null)
     mListener.onSetVisibilityCalled();
 }

}