Question

Is it possible to “link” UILabel text property with another NSString so that when this other NSString is changed also UILabel text property changes?

Example:

UILabel *label = [[UILabel alloc] init];  
NSString *str = @"labelText1";  
label.text = str;  
str = @"labelText2"; //after this assignment label.text is still "labelText1"

Answer 1

In your question you haven’t “changed” any objects – NSString instances are immutable, and you’ve just said that some variable points to one instance instead of another. Assuming that your string is really a property of some other model object, you could have your controller observe that property (with -observeValueForKeyPath:ofObject:change:context) and update the label every time it sees a change.