判断textView还能输入多少字

//改变label上的数字

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

{  

    //不允许继续输入

   if (range.location >140) {

       return NO;

    }  

    returnYES;

}

- (void)textViewDidChange:(UITextView *)textView

{

    _label.text = [NSStringstringWithFormat:@"%d",140 - _textView.text.length];

    

   if ((_textView.text.length) == 0) {

       sendMessage.enabled =NO;

    }else{

       sendMessage.enabled =YES;

    }

    

}