TextField和TextView限制输入字数长度

 - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{ NSInteger existedLength = textField.text.length; NSInteger selectedLength = range.length; NSInteger replaceLength = string.length; NSInteger pointLength = existedLength - selectedLength + replaceLength; //超过16位 就不能在输入了 if (pointLength > 16) {  return NO; }else{  return YES; } } 

 -(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString*)text{ //这个判断相当于是textfield中的点击return的代理方法 if ([text isEqualToString:@"/n"]) {  [textView resignFirstResponder];  return NO; }  //在输入过程中 判断加上输入的字符 是否超过限定字数 NSString *str = [NSString stringWithFormat:@"%@%@", textView.text, text]; if (str.length > 500) {  textView.text = [textView.text substringToIndex:500];  return NO; } return YES;}