UITextView "Field" - objective-c

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)];
}

Answer 2

NSLog(#"You added a character");
charactersLeft--;
I think the problem here is that you should have written:
charactersLeft -= text.length;

Answer 3

In viewDidLoad :
charactersLeft = 140;
characterCountLabel.text = [NSString stringWithFormat:#"%d",charactersLeft];
Now use this it works well :
- (void)textViewDidChange:(UITextView *)textView{
NSString *textString = textView.text;
int chars = [textString length];
if (chars <= 140) {
[characterCountLabel setText:[NSString stringWithFormat:#"%d",(140 - chars)]];
}
}
-(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
if([text isEqualToString:#"\n"])
[textView resignFirstResponder];
if (textView.text.length == 140 && [text isEqualToString:#"\n"]) {
[textView resignFirstResponder];
}
else if ((textView.text.length) >= 140 && range.length == 0){
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"" message:#"You have exceeded the characters limit." delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil];
[alert show];
[alert release];
return NO; // return NO to not change text
}
return YES;
}
Note that here I have used returnType key to resign the keyboard.You may change it to work as usual.