- (IBAction)saveEmailAction:(id)sender {  
         if ([self  isValidateEmail:_mailField.text])  
         {  
             [self.delegate saveEmail:_mailField.text];  
             [self.navigationController popViewControllerAnimated:YES];  
         }  
        else  
        {  
            UIAlertView *error=[[UIAlertView alloc]initWithTitle:@"提示" message:@"请输入正确邮箱" delegate:self cancelButtonTitle:@"确定" otherButtonTitles:nil];  
            [error show];  
        }  
    }  
      
      
    -(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];  
    }