UitextView + NSUndoManager

[elio.d]

I'm trying to integrate the undo/redo features in a UITextView (I'm building a LateX editor) with no luck and to be honest I'm really confused about this argument. I don't understand the steps involved in those two operations, I mean I need two methods
- one to remove the last inserted text
- one to restore the text removed

one doubt is where I get the last inserted text? in other words where I have to register for the undo?

- in textViewDidChange I can get the whole text
- in textViewShouldChangeTextInRange I can get the last char inserted

I know that what I write isn't the best explanation ever, But I hope someone here has faced the same problem in the past and can give me an hint. Basically ,to resume, I have to add the undo/redo features to a textview.

Thanks in advance

[elio.d]

a little bump with an update. So my problem was to make my textView capable of undo/redo action ( I use two buttons to do this ). Reading the doc I discovered that UITextView has a built-in undoManager and his basic usage is really simple. What I've done so far?

I've a viewController (EditorViewController) containing the textView.

- in EditorViewcontroller.h

 NSUndoManager *myUndoManager;

- in EditorViewController.m --> viewDidLoad

 myUndoManager = [textView undoManager];

as I said two buttons are used to perform undo/redo actions, thos two buttons are located into the inputAccessoryView of the textView, this view is basically a toolbar with several button used to append text to the textView.
I've a method called appendText:

- (IBAction) appendText:(id)sender{
	
	NSString *contentsToAdd;
	NSMutableString *textViewContent;
	NSRange cursorPosition;
	if ([undoManager canUndo]) {
		NSLog(@"yes canundo");
	}
	switch ([sender tag]) {
	  case 0:
	    [textView setScrollEnabled:NO];
	    
            contentsToAdd = @"[]";   
	    
            cursorPosition = [textView selectedRange];
            
            textViewContent = [[NSMutableString alloc] 
                                 initWithString:[textView text]];
	    
            [textViewContent insertString:contentsToAdd 
                                          atIndex:cursorPosition.location];
	    
           [textView setText:tfContent];

            [tfContent release];
	    cursorPosition.location++;
            textView.selectedRange=cursorPosition;

	    [textView becomeFirstResponder];
	    [textView setScrollEnabled:YES];
	     if (![undoManager canUndo]) {
		    NSLog(@" can't undo");
	     }	
	     break;
            // more case following 0..9
            case 10:
             [myUndoManager undo];
             [break];  
            case 11 :
             [myUndoManager redo];
             break;
}

Now things works well if I write using the keyboard, I mean undo and redo works properly. But when I append some text using the appendText: method, undo and redo aren't performed.If I begin to write again using the keyboard undo and redo are performed(the first element of the undo stack is last text written) It's like if the undo and redo stack are cleared every time I append some text. I hope someone can give me an hint..

[macguru17]

I've found a working solution and thought you might be interested in it. To avoid double-posting, please have a look at my answer on Stack Overflow.