Difference between ChangeListener and ItemListener

Question

What is the difference between ChangeListener and ItemListener for JCheckBox and JRadioButton? Both of them work fine when they are selected/deselected.

I know that some components doesn't support ChangeListener like the JComboBox. Other than the reason that ChangeListener or ItemListener work for only some components. Is there any difference between them like when are they generated?

Any answer is appreciated. Thanks in advance.

Answer 1

both listeners for JCheckBox work similarly in that both will fire event upon change in state, whether by clicking or toggle by spacebar or programmatically through doClick() method (Similar to mouse click). One major difference though is that JCheckBox’s itemListener can be fired through setSelected(boolean) method which allows one to fire the event based on desired state whereas others will act only after the state is altered. So why is it important ? Consider when application startup, the GUI needed to configure for defined state, and using setSelected will trigger ItemListener. Note that setSelected is exclusive to ItemListener and has no effect on ActionListener. Do not register both ActionListener and ItemListener as both will be fired, landing the component in a random state

Answer 2

ChangeListener is notyfied when there's any change to the button state. ChangeListener is not notified of what has changed, only that the object has changed. Item listener is only notyfied when an item is selected; by user or setSelected method. It's also not true that ChangeListener is not notyfied when setSelected method is invoked. It is the change of the object state.