Why is my JTextArea working as a TableCellEditor?

Question

Hello all,
I have implemented a CellEditor using a JTextArea as the editing component because I need to handle multiline contents.
So far everything works fine. I can start editing the contents by doublecklicking. And the input is accepted when I select a different cell in my table, the changes are discarded when I hit ESC.
After searching this forum and google for a while on this topic (because there are some problems I couldn't solve so far, see below) I am puzzled that it is working at all!
The basic layout of my component is, that I have a JTextPane inside a JScrollPane. My class implements the TableCellEditor interface.
getTableCellEditorComponent() returns the scroll pane
getCellEditorValue() returns the contents of the JTextArea
isCellEditable() checks for a doubleclick in case of a MouseEvent
otherwise returns true (stolen from DefaultCellEditor);
stopCellEditing() and cancelCellEditing() do nothing apart from notifying any listeners.
Interesting enough stopCellEditing() and cancelCellEditing() are never called even though editing works as expected. What am I missing here???
My expectation was that those methods are called when I leave the editing cell (stopCellEditing) or if I hit ESC (cancelCellEditing())
If they don't get called, why is the new value actually applied to my table model?
But I still have another problem which I cannot solve.
I'm trying to make this editor behave like the defaultCellEditor:
- start editing as soon as a key gets typed (if that cell has the focus). Somehow the editing is started but seems to end right away.
Same with hitting F2. I have the impression that the focus is set to the ScrollPane rather than to the TextArea because the component returned by getEditorCellComponent() is the ScrollPane. How can I change this? If I return the TextArea, it is not scrollable...
- Jump to the next cell when TAB is pressed. Currently the TAB character is inserted. I have tried overwriting isManagingFocus() on the editor component, the scroll pane and my editor itself, but to no avail.
- End the editing when the ENTER key is pressed (Ctrl-ENTER should insert a new line).
From all I read in this forum and the newsgroups, this should be handled by the ActionMap/InputMap, but I don't know which actions I should use to achieve this goal (i.e. which action makes the table stop the editing and move to the next column)
Any help is greatly appreciated!
Cheers
Thomas

Answer 1

Complicated little beast, is it?
To have control over the real editing that's taking place, you have to subclass JTextArea and override the processKeyBinding method.
Interesting enough stopCellEditing() and cancelCellEditing() are never called.You have to call these methods yourself when certain keys are detected in processKeyBinding
- start editing as soon as a key gets typed (if that cell has the focus).Override the processKeyBinding in JTable to have better control of the keytype event. If you detected a key that signal the start of editing, you must go thru the motion of setting up the editor, etc... just like JTable does. Then, as a final step, give focus to your edit component and dispatch the key type event to it (be careful because several events are fired by simply pressing a single character on the keybaord). This very last step may have to be put into SwingUtilities.invokeLater if you find that the event is fired before your editor is ready).
- Jump to the next cell when TAB is pressed.
- End the editing when the ENTER key is pressed (Ctrl-ENTER should insert a new line).Again, you can trap TAB, ENTER, Ctrl-ENTER in processKeyBinding and do whatever your heart desired.
Whew........... anyway, if you want to see a working model, check it out at the link shown below:
http://home.attbi.com/~aokabc/ABC/AOKabc.htm
;o)
V.V.