- (void)viewDidLoad{    [super viewDidLoad];    // Do any additional setup after loading the view.        self.title=@"验证邮箱的合法性";        NSString *email=@"123456@qq.com";    NSLog(@"--%i-",[self isValidateEmail:email]);    }//用正则表达式-(BOOL)isValidateEmail:(NSString *)email {        NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";        NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];        return [emailTest evaluateWithObject:email];    }