Detecting selection change on a UITextView?

Question

Is there a way to detect when the user changes the range of the selected text in a textview (In a subclass of UITextView)? I couldn't find any NSNotification. I tried observing keyvalues but the observer for selected range does not get called

[self addObserver:self forKeyPath:@"selectedRange" options:NSKeyValueObservingOptionNew context:nil];

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if ([keyPath isEqual:@"selectedRange"])
    {
        // Do stuff
    }
}

I DO NOT want to use the delegate method of UITextView

Answer 1

UITextView adopts the UITextInput protocol. That protocol includes a required selectedTextRange read/write property. That is the property you want to respond to changes of.

While you could observe that property, the simplest approach is to override the -setSelectedTextRange: method in your subclass and perform whatever additional behaviours you need in there. (You may or may not want to confirm that the range is actually changing, depending on your particular design.)

Answer 2

UITextView's delegate () conforms to this since iOS2

-(void)textViewDidChangeSelection:(UITextView *)textView {
    //read textView.selectedRange
}

I also personally like to manually trigger it when dismissing a keyboard since that also is a selection change in my opinion but won't trigger the delegate callback on its own (an overlooking on Apple's part in my humble opinion)

-(void)textViewDidEndEditing:(UITextView *)textView {
    textView.selectedRange = NSMakeRange(0, 0);
    [self textViewDidChangeSelection:textView];
}