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How to add Undo and Redo actions to JPanel

Digen Mahara
Greenhorn

Joined: Dec 23, 2011
Posts: 23

I am trying to make a paint application and want to add undo and redo functions to it how can I do this

I have used UndoManager class with TextComponents but really confused with Containers like JPanel where you actually draw images



Please Help !!!


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Campbell Ritchie
Sheriff

Joined: Oct 13, 2005
Posts: 38392
    
  23
Undo Manager appears only to work with text components.
How are you drawing your images? Do you have some sort of ImageComponent class or similar? Can you put ImageComponents into some sort of List and go back and forth along the List?
Paul Clapham
Bartender

Joined: Oct 14, 2005
Posts: 18541
    
    8

Campbell Ritchie wrote:Undo Manager appears only to work with text components.


Not at all. UndoManager can work with any kind of edits at all. It's just that you have to write a subclass of UndoableEdit which essentially stores the "before" and "after" states in such a way that the undo() and redo() methods modify the view appropriately. For example an edit for a checkbox might look like this (not all required methods implemented):
Campbell Ritchie
Sheriff

Joined: Oct 13, 2005
Posts: 38392
    
  23
I was mistaken, obviously. Sorry.
 
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subject: How to add Undo and Redo actions to JPanel