How to catch events in a component returned by a renderer

Question

Hi All,
I have two questions actually, both on event-handling.
1. re subject
I have a renderer (DefaultTableCellRenderer) which is to pain tablecolumns header (TableColumnInst.setHeaderRenderer(new myrenderer))
In the (abovementioned) renderer I return a JPanel of which a Jbutton is added, and I add an actionlistenter (anonym class) to that button. The problem is when the header displays well with the button, I cannot do anything that would make my actionlistener's actionperformed run.
Saw two possible solutions:
- using AWTEventListener : not okay for me 'cause having an applet that has some security problems with it
- defining the renderer as a class that implements the celleditor interface : can't set a tablecolumn-headers' editor.
2. When I add an element to a JComboBox (with for instance setting a checkbox) the combobox's itemstatechenged runs. Who could I distinguish a selection made by mouse clicks and another one that is caused by adding elements and jcombobox selects an element automatically.
Any help is really appreciated
Cheers
Mate

Answer 1

As you've found, adding listeners to a table cell renderer object won't do anything. The renderer objects are not permanently added to the JTable or JTableHeader's child component list. They are simply used to provide the correct paint() method to render the cell. (i.e. The table's paint method simply renders each cell by grabbing the correct cell renderer object, temporarily adding it to the component tree and directly calling it's paint() method.)
The framework is designed to allow you to use the same instance of the renderer on multiple cells, thus allowing large tables to exist with minimal memory usage and performance penalty.
The way you handle mouse and keyboard events is to handle them in the parent object. In your case, this would be the JTableHeader object. Then inside the JTableHeader's event handler you can determine what column they are on by calling JTableHeader.columnAtPoint(Point) method and take the appropriate action.