Question

I would like a text similar to Twitter’s

I am currently using a UITextView since it has multi-line support. I kind of figured out how to use a label that counts the characters and keeps the user up to date of any characters added or removed.

Empty:

With Text:

The problem I am having however is when I copy or paste any text in the view, (like if I highlight all the text, as in the second picture) and I delete it, the counter will not update. Or if I paste any text, the count just decrements one character, though the text field limit still stays correct, just the counter is no longer in sync with it.

Code: http://pastebin.com/UK91Ccbb

Answer 1

There is a delegate method for UITextView as

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text;

it is called every time a character is inserted into the UITextView. In this method set the length of text in your counter UILabel as follows

counterlabel.text = [NSString stringWithFormat:@"%i", textView.text.length];

return YES at the end of method if the length is within range i.e. less than or equal to 140 else return NO.

UPDATE:..
To restrict to 140 characters.

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
    return textView.text.length <= 140;

}

To handle text removal on selection and counting characters.

- (void)textViewDidChange:(UITextView *)textView
{
    count.text = [NSString stringWithFormat:@"%i", (140- textView.text.length)];
}