texfield只能输入数字和字母

texfield只能输入数字和字母

 

#define kPasswordNum   @"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"

 

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string;{ 

    

        NSCharacterSet *chars = [[NSCharacterSet characterSetWithCharactersInString:kPasswordNum] invertedSet];

        NSString *filtered =[[string componentsSeparatedByCharactersInSet:chars] componentsJoinedByString:@""];

        BOOL basic = [string isEqualToString:filtered];

        return basic;

}