ios - Detect moment when newline starts in UITextView

Question

I try to detect when carriage goes at new line in UITextView. I can detect it by comparison total later width with UITextView width:

CGSize size = [textView.text sizeWithAttributes:textView.typingAttributes];
if(size.width > textView.bounds.size.width)
      NSLog (@"New line");

But it dose not work proper way because -sizeWithAttributes:textView returns only width of letters without indentation width. Help please solve this.

Answer 1

This is how I would do it:

• Get the UITextPosition of the last character.
• Call caretRectForPosition on your UITextView.
• Create a CGRect variable and initially store CGRectZero in it.
• In your textViewDidChange: method, call caretRectForPosition: by passing the UITextPosition.
• Compare it with the current value stored in the CGRect variable. If the new y-origin of the caretRect is greater than the last one, it means a new line has been reached.

Sample code:

CGRect previousRect = CGRectZero;
- (void)textViewDidChange:(UITextView *)textView{

    UITextPosition* pos = yourTextView.endOfDocument;//explore others like beginningOfDocument if you want to customize the behaviour
    CGRect currentRect = [yourTextView caretRectForPosition:pos];

    if (currentRect.origin.y > previousRect.origin.y){
            //new line reached, write your code
        }
    previousRect = currentRect;

}

Also, you should read the documentation for UITextInput protocol reference here. It is magical, I'm telling you.

Let me know if you have any other issues with this.