Question

In Android can one use/implement a listener that fires a callback when the number of children for a given View changes dynamically? Say for example a View has 3 immediate children, and one is removed through code, I need an event to fire to say that the number of immediate children has changed.

To clarify, I don’t need to perform a depth traversal on the View tree to count children, I’m just interested in counting the number of children at the first layer of a given View.

Many thanks

Answer 1

I believe that you want to use the OnHierarchyChangeListener:

Interface definition for a callback to be invoked when the hierarchy within this view changed. The hierarchy changes whenever a child is added to or removed from this view.

It has two callbacks:

• onChildViewAdded()
• onChildViewRemoved()