UITextView

1~监听textView

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text{    if (1 == range.length) {//按下回格键        return YES;    }       if ([text isEqualToString:@"\n"]) {//按下return键        //这里隐藏键盘，不做任何处理        [textView resignFirstResponder];        return NO;    }else {        if ([textView.text length] < 140) {//判断字符个数            return YES;        }      }    return NO;//也可以是YES}