Re: Out-of-order Undos and NSTextField [SOLVED, well sort of]
Re: Out-of-order Undos and NSTextField [SOLVED, well sort of]
- Subject: Re: Out-of-order Undos and NSTextField [SOLVED, well sort of]
- From: James Bucanek <email@hidden>
- Date: Tue, 11 Jul 2006 12:05:53 -0700
After messing around with this problem, I found an almost acceptable solution. This is a bit hacky, and I fear there are unpredicatble side-effect, but it seems to be working in my application OK.
The hack is to sub-class NSTextField, then intercept one of the delegate messages sent to NSTextField from the NSTextView that gets created as the field's editor. I wish there was a textViewWillBeginEditing:, but I settled for textView:shouldChangeTextInRange:replacementString: which gets invoked whenever the user tries to add/remove/replace any text. Before the message is passed on to the real NSTextField, I simply turn off undo support in the field editor.
Hopefully this will solve someone else's problem, or at least encourage someone to find a better solution.
------------- /Users/james/Desktop/UndoableTextField.h
//
// UndoableTextField.h
// QRecall
//
// Created by James Bucanek on 7/11/06.
//
#import <Cocoa/Cocoa.h>
//
// An NSTextField that does not use the undo manager.
//
// NSTextField/NSTextView has this nasty habid of registering undo actions out of order.
// This is used in windows where the text field is bound to a property that is already
// registering undo actions based on the changes in its value and we don't need the field
// editor registering superfluous text edit changes at the same time.
//
// Notes:
// The object works by intercepting the textView:shouldChangeTextInRange:replacementString:
// delegate message sent to the text field whenever the user tries to change the text.
// Before passing the message on, it disables undo on the NSTextView that is being used
// as the field editor.
// This won't work for more complex cases where the user changes the font or
// other attributes of the text first. It also might mess up other fields that reuse
// the NSTextView object.
@interface UndoableTextField : NSTextField
- (BOOL)textView:(NSTextView*)textView shouldChangeTextInRange:(NSRange)affectedCharRange replacementString:(NSString*)replacementString;
@end
------------- /Users/james/Desktop/UndoableTextField.m
//
// UndoableTextField.m
// QRecall
//
// Created by James Bucanek on 7/11/06.
//
#import "UndoableTextField.h"
@implementation UndoableTextField
- (BOOL)textView:(NSTextView*)textView shouldChangeTextInRange:(NSRange)affectedCharRange replacementString:(NSString*)replacementString
{
[textView setAllowsUndo:NO]; // turn off Undo before the user changes anything
// NSTextField should implement textView:shouldChangeTextInRange:replacementString:, but just to be on the safe side...
if ([super respondsToSelector:@selector(textView:shouldChangeTextInRange:replacementString:)])
return ([super textView:textView shouldChangeTextInRange:affectedCharRange replacementString:replacementString]);
return (YES);
}
@end
--
James Bucanek
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