Objective-C - UITextField输入长度限制

UITextField类没有最大长度属性, 需要通过Delegate设置.
1.继承UITextFieldDelegate接口.

@interface MYClass () <UITextFieldDelegate>
@end

2.设置接口.

// timesField: 初始化的UITextField
[timesField setDelegate:self]; // 设置限制长度

3.重写函数:

#pragma mark UITextFieldDelegate
-               (BOOL)textField:(UITextField *)textField
  shouldChangeCharactersInRange:(NSRange)range
              replacementString:(NSString *)string {
    // 避免崩溃
    if(range.length + range.location > textField.text.length){
        return NO;
    }
    NSUInteger newLength = [textField.text length] + [string length] - range.length;
    // 设置限制长度
    return newLength <= 2;
}