一:正则表达式再用    #pragma 正则匹配手机号  + (BOOL)checkTelNumber:(NSString *) telNumber  {       NSString *pattern = @^ 1 +[ 3578 ]+\d{ 9 };       NSPredicate *pred = [NSPredicate predicateWithFormat: @SELF MATCHES %@, pattern];       BOOL isMatch = [pred evaluateWithObject:telNumber];       return isMatch;  }        #pragma 正则匹配用户密码 6 - 18 位数字和字母组合  + (BOOL)checkPassword:(NSString *) password  {       NSString *pattern = @^(?![ 0 - 9 ]+$)(?![a-zA-Z]+$)[a-zA-Z0- 9 ]{ 6 , 18 };       NSPredicate *pred = [NSPredicate predicateWithFormat: @SELF MATCHES %@, pattern];       BOOL isMatch = [pred evaluateWithObject:password];       return isMatch;          }     #pragma 正则匹配用户姓名, 20 位的中文或英文  + (BOOL)checkUserName : (NSString *) userName  {       NSString *pattern = @^[a-zA-Z一-龥]{ 1 , 20 };       NSPredicate *pred = [NSPredicate predicateWithFormat: @SELF MATCHES %@, pattern];       BOOL isMatch = [pred evaluateWithObject:userName];       return isMatch;          }        #pragma 正则匹配用户身份证号 15 或 18 位  + (BOOL)checkUserIdCard: (NSString *) idCard  {       NSString *pattern = @(^[ 0 - 9 ]{ 15 }$)|([ 0 - 9 ]{ 17 }([ 0 - 9 ]|X)$);       NSPredicate *pred = [NSPredicate predicateWithFormat: @SELF MATCHES %@, pattern];       BOOL isMatch = [pred evaluateWithObject:idCard];       return isMatch;  }     #pragma 正则匹员工号, 12 位的数字  + (BOOL)checkEmployeeNumber : (NSString *) number  {       NSString *pattern = @^[ 0 - 9 ]{ 12 };               NSPredicate *pred = [NSPredicate predicateWithFormat: @SELF MATCHES %@, pattern];       BOOL isMatch = [pred evaluateWithObject:number];       return isMatch;          }     #pragma 正则匹配URL  + (BOOL)checkURL : (NSString *) url  {       NSString *pattern = @^[ 0 -9A-Za-z]{ 1 , 50 };       NSPredicate *pred = [NSPredicate predicateWithFormat: @SELF MATCHES %@, pattern];       BOOL isMatch = [pred evaluateWithObject:url];       return isMatch;            }  二 TextFiled的代理方法    //////// 特殊字符的限制输入，价格金额的有效性判断    #define myDotNumbers     @"0123456789.\n"  #define myNumbers          @"0123456789\n"  -(void) createTextFiled {      textfield1_ = [[UITextField alloc] initWithFrame:CGRectMake(0, 0, 20, 20)];      textfield1_.delegate = self;      [self addSubview:textfield1_];         textfield2_ = [[UITextField alloc] initWithFrame:CGRectMake(0, 0, 20, 20)];      textfield2_.delegate = self;      [self addSubview:textfield2_];         textfield3_ = [[UITextField alloc] initWithFrame:CGRectMake(0, 0, 20, 20)];      textfield3_.delegate = self;      [self addSubview:textfield3_];    }    -(void)showMyMessage:(NSString*)aInfo {        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"提示" message:aInfo delegate:self cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];      [alertView show];      [alertView release];    }    - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {      NSCharacterSet *cs;      if ([textField isEqual:textfield1_]) {          cs = [[NSCharacterSet characterSetWithCharactersInString:myNumbers] invertedSet];          NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];          BOOL basicTest = [string isEqualToString:filtered];          if (!basicTest) {              [self showMyMessage:@"只能输入数字"];              return NO;          }      }      else if ([textField isEqual:textfield2_]) {          cs = [[NSCharacterSet characterSetWithCharactersInString:myNumbers] invertedSet];          NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];          BOOL basicTest = [string isEqualToString:filtered];          if (!basicTest) {              [self showMyMessage:@"只能输入数字"];              return NO;          }      }      else if ([textField isEqual:textfield3_]) {          NSUInteger nDotLoc = [textField.text rangeOfString:@"."].location;          if (NSNotFound == nDotLoc && 0 != range.location) {              cs = [[NSCharacterSet characterSetWithCharactersInString:myDotNumbers] invertedSet];          }          else {              cs = [[NSCharacterSet characterSetWithCharactersInString:myNumbers] invertedSet];          }          NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];          BOOL basicTest = [string isEqualToString:filtered];          if (!basicTest) {                [self showMyMessage:@"只能输入数字和小数点"];              return NO;          }          if (NSNotFound != nDotLoc && range.location > nDotLoc + 3) {              [self showMyMessage:@"小数点后最多三位"];              return NO;          }      }      return YES;  }