1

The particular thing I'm interested in at the moment is JTable's 'cancel' Action ... in particular I'm trying to find out why, with an InputVerifier set for the JTable's CellEditor's Component (JTextField), the IV's shouldYieldFocus() method is called not once, but twice (!) when I press Escape.

I have checked that it is the JTable's ActionMap entry for VK_CANCEL ('cancel') which is being run here.

Furthermore I find that the JTable's editingCanceled method is NOT called when I press Escape like this... and this in turn makes is slightly difficult currently to let the IV know that a cancellation action is happening (and that verify should not therefore be called).

Of course it's easy enough to create my own "Cancel" Action, which calls the cancel Action obtained from the JTable's ActionMap, but also sets a flag saying "disregard the text of the JTF... we're cancelling". But I'd just like to see what the cancellation Action actually consist of... i.e. the code.

later
Having had a look at the source code for one or two classes, in particular JComponent and AbstractCellEditor, it appears that the IV's shouldYieldFocus is triggered, perhaps not that surprisingly, when a request to take focus away is made.

I haven't yet solved my specific problem, and I'd still like to know if it's possible to find the code of these ActionMap Actions...

trashgod
  • 203,806
  • 29
  • 246
  • 1,045
mike rodent
  • 14,126
  • 11
  • 103
  • 157
  • If you use a jdk, the source code is already supplied. Just set a breakpoint in your `shouldYieldFocus` method and look up the call chain… – Holger Jul 27 '15 at 17:04
  • Thanks... in fact I'm a Jython fanatic so this isn't an option with my app code. Although of course I can rustle up a little Java experiment if need be! – mike rodent Jul 27 '15 at 17:07
  • Actually, come to think of ... I did examine the stack to try to yield exactly that: where's this call coming from? When you press Enter, CellEditor.stopCellEditing is called and IV.shouldYieldFocus from that... but with the two calls triggered by the 'cancel' Action following an Escape key press, IV.shouldYieldFocus is the ***first*** call... meaning that it is actually a command in Runnable.run() as run by ... something. – mike rodent Jul 27 '15 at 17:22

1 Answers1

2

Yes. As discussed here, and illustrated here, subclasses of TextAction are installed as key bindings by the text component's UI delegate, typically a subclass of BasicTextUI. Each Action is typically an instance of a class nested in the relevant editor kit. For example, DefaultEditorKit includes several public actions, as well as a larger number of package-private actions used internally.

The handler for the Action named "cancel" may be found, among others, in the JTable UI delegate, typically a subclass of BasicTableUI.

As noted in Validating Input, ensure that your implementation of verify() has no side effects. A complete example is examined here. Examples using an InputVerifier in a TableCellEditor are seen here and here.

Actions and keys bound WHEN_FOCUSED to JTextField by com.apple.laf.AquaLookAndFeel:

beep:
caret-backward: LEFT, KP_LEFT, ctrl B
caret-begin: ctrl P, meta UP, meta KP_UP, HOME
caret-begin-line: KP_UP, ctrl A, UP, meta KP_LEFT, meta LEFT
caret-begin-paragraph:
caret-begin-word:
caret-down:
caret-end: ctrl N, END, meta KP_DOWN, ctrl V, meta DOWN
caret-end-line: DOWN, meta KP_RIGHT, ctrl E, meta RIGHT, KP_DOWN
caret-end-paragraph:
caret-end-word:
caret-forward: RIGHT, ctrl F, KP_RIGHT
caret-next-word: alt KP_RIGHT, alt RIGHT
caret-previous-word: alt KP_LEFT, alt LEFT
caret-up:
copy:
copy-to-clipboard: meta C, COPY
cut:
cut-to-clipboard: CUT, meta X
default-typed:
delete-next: DELETE, ctrl D
delete-next-word: alt DELETE
delete-previous: BACK_SPACE, ctrl H
delete-previous-word: alt BACK_SPACE, ctrl W
dump-model:
insert-break:
insert-content:
insert-tab:
notify-field-accept: ENTER
page-down:
page-up:
paste:
paste-from-clipboard: meta V, PASTE
requestFocus:
select-all: meta A
select-line:
select-paragraph:
select-word:
selection-backward: shift LEFT, shift KP_LEFT
selection-begin: shift meta KP_UP, shift meta UP, shift HOME
selection-begin-line: shift UP, shift meta KP_LEFT, shift KP_UP, shift meta LEFT
selection-begin-paragraph:
selection-begin-word:
selection-down:
selection-end: shift meta DOWN, shift meta KP_DOWN, shift END
selection-end-line: shift meta KP_RIGHT, shift DOWN, shift KP_DOWN, shift meta RIGHT
selection-end-paragraph:
selection-end-word:
selection-forward: shift KP_RIGHT, shift RIGHT
selection-next-word: shift alt KP_RIGHT, shift alt RIGHT
selection-page-down: shift PAGE_DOWN
selection-page-left: shift meta PAGE_UP
selection-page-right: shift meta PAGE_DOWN
selection-page-up: shift PAGE_UP
selection-previous-word: shift alt LEFT, shift alt KP_LEFT
selection-up:
set-read-only:
set-writable:
toggle-componentOrientation: shift ctrl O
unselect: meta BACK_SLASH
Community
  • 1
  • 1
trashgod
  • 203,806
  • 29
  • 246
  • 1,045
  • thanks... in fact it is not the key bindings of a JTextComponent that I'm (currently) interested in exploring. Note that 'cancel' is absent from your list... this in fact belongs to JTable's ActionMap (or parent or grandparent thereof). When editing, as I'm sure you know, the editor's component, in my case a JTextField, becomes a child component of the JTable... as it fails to intercept a VK_CANCEL keystroke this is passed on to the JTable. I'm still not clear where in the source code I can find the code for JTable's 'cancel' Action... – mike rodent Jul 28 '15 at 12:24
  • Oh, _that_ one! It's handled in `BasicTableUI`. – trashgod Jul 28 '15 at 16:19