Button Event Handler in a JList, Please help.

Question

Hi everyone,
I have created a small Java application which has a JList. The JList uses a custom cell renderer I named SmartCellRenderer. The SmartCellRenderer extends JPanel and implements the ListCellRenderer. I have added two buttons on the right side inside the JPanel of the SmartCellRenderer, since I want to buttons for each list item, and I have added mouse/action listeners for both buttons. However, they don't respond. It seems that the JList property overcomes the buttons underneath it. So the buttons never really get clicked because before that happens the JList item is being selected beforehand. I've tried everything. I've put listeners in the Main class, called Editor, which has the JList and also have listeners in the SmartCellRenderer itself and none of them get invoked.
I also tried a manual solution. Every time the event handler for the JList was invoked (this is the handler for the JList itself and not the buttons), I sent the mouse event object to the SmartCellRenderer to manually check if the point the click happened was on one of the buttons in order to handle it.
I used:
// Inside SmartCellRenderer.java
// e is the mouse event object being passed from the Editor whenever
// a JList item is selected or clicked on
Component comp = this.getComponent (e.getX(), e.getY())
if(!(comp instanceof JButton)) {
          System.out.println("Recoqnized Event, but not a button click...");
          //return;
} else {
          System.out.println("Recognized Event, IT IS A MOUSE CLICK, PROCESSING...");
          System.out.println("VALUE: "+comp.toString());
What I realized is that not only this still doesn't work (it never realizes the component as a JButton) it also throws an exception for the last line saying comp is null. Meaning with the passed x,y position the getComponent() returns a null which happens when the coordinates passed to it are outside the range of the Panel. Which is a whole other problem?
I have yet to find an example on the web, using Google, that demonstrated using buttons inside a JList.
Can anyone help me with this. Thanks.

Answer 1

A renderer is not a component, so you can't click on it. A renderer is just used to paint a representation of a component at a certain position in your JList.
I have yet to find an example on the web, using Google, that demonstrated using buttons inside a JList.Thats probably because this is not a common design. The following two designs are more common:
a) Create a separate panel for your JButtons. Then when you click on the button it would act on each selected row in the JList
b) Or maybe like windows explorer. Select the items in the list and then use a JPopupMenu to perform the desired functionality.
I've never tried to add a clickable button to a panel, but this [url http://forum.java.sun.com/thread.jspa?threadID=573721]posting shows one way to add a clickable JButton as a column in a JTable. You might be able to use some of the concepts to add 2 button to the JPanel or maybe you could use a JTable with 3 columns, one for your data and the last two for your buttons.