How to observe changes to an NSTextStorage

Question

I have an NSTextStorage delegate imlementing textStorageDidProcessEditing: . Unfortunately, the userInfo doesn't contain any details about the changes to the text.

How can I find out what actually changed?

Ideally I'd like to know everything sent to [NSLayoutManager textStorage:edited:range:changeInLength:invalidatedRange:] , but just the edited range would be good enough.

Answer 1

您可以编写自己的NSLayoutManager子类，然后使用addLayoutManager:将其添加到NSTextSTorage中。

Answer 2

您还可以使用KVO观察NSTextStorage对象的characters属性（或它的任何其他属性），然后确切地了解其中的更改

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context 

Answer 3

使用NSTextStorage的getter方法editedRange和changeInLength。