如何验证文本字段

Question

在我的应用程序中，我使用一个文本字段作为电子邮件，另一个文本字段作为用户名和按钮，输入数据后在按钮事件下编写代码单击按钮显示另一个视图，我的问题是编写电子邮件验证代码（[电子邮件受保护] 以这种格式）这些警报视图在单击按钮时显示（消息输入正确的电子邮件格式），但我想要显示这些警报移动到下一个文本字段假设我以错误的格式输入了电子邮件并将电影发送到下一个字段，此时将显示电子邮件警报视图的用户名文本字段。

Answer 1

使用 NSPredicate 和 Regex：

- (BOOL)validateEmailString:(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];
}

对于用逗号 (,) 分隔的电子邮件：

- (NSMutableArray*)validateEmailWithString:(NSString*)emails
{
    NSMutableArray *emails = [[NSMutableArray alloc] init];
    NSArray *emailOfArray = [emails componentsSeparatedByString:@","];
    for (NSString *email in emailOfArray)
    {
        NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}"; 
        NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex]; 
        if ([emailTest evaluateWithObject:email])
            [emails addObject:email];
    }
    return [emails autorelease];
}

Answer 2

检查此处。电子邮件验证

Answer 3

我已经在 editingDidEnd 事件上验证了我的字段并使用了以下代码：

 - (IBAction) emailValidation:(id)sender {
NSString *eml=((UITextField *)sender).text;

NSString *regex = @"\\b([a-zA-Z0-9%_.+\\-]+)@([a-zA-Z0-9.\\-]+?\\.[a-zA-Z]{2,6})\\b"; 

NSPredicate * regextest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];

BOOL x= [regextest evaluateWithObject:eml];

if (x==FALSE) {
    UIAlertView *alert=[[UIAlertView alloc]initWithTitle:@"Errror!" message:@"You have entered incorrect email ID" delegate:self cancelButtonTitle:@"Wanna Correct" otherButtonTitles:nil];
    [alert show];
    [emailField becomeFirstResponder];
    [alert release];    
}   
}

-(IBAction)passwordValidator:(id)sender{
NSString *pwd=[NSString stringWithString:passwordField.text];
int lngth=[pwd length]; 
int minlength=6;

NSString *regex = @"\\b([a-zA-Z0-9]+)\\b"; 

NSPredicate * regextest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];

BOOL x= [regextest evaluateWithObject:pwd];

if (lngth>=minlength) {
    NSLog(@"passoword length is enough");
    if (x==FALSE) {
        NSLog(@"Special charector check enabled");
        UIAlertView *alert=[[UIAlertView alloc]initWithTitle:@"No Special Charectors" message:@"please don't use special charectors" delegate:self cancelButtonTitle:@"Wanna Correct" otherButtonTitles:nil];
        [alert show];
        [alert release];
        [passwordField becomeFirstResponder];
        [self.view addSubview:passwordField];
    }
}
else {
    UIAlertView *alert=[[UIAlertView alloc]initWithTitle:@"Poor length" message:@"Password length must not be less than 8.." delegate:self cancelButtonTitle:@"Wanna Correct" otherButtonTitles:nil];
    [alert show];
    [alert release];
    [passwordField becomeFirstResponder];
}
}

尝试这些，然后在任何相关事件上调用，您将获得所需的结果。祝你好运 ：）