驗證多個uitextfield

我使用此代碼來檢查文本字段是否爲空。第一次，它會起作用，但當我更改文本字段值時，警報不起作用。驗證多個uitextfield

-(void)sendclick { 
     NSString *msg; 
     if(firstnametextfield.text==NULL) { 
      [email protected]"enter first name"; 
      NSLog(@"%@",firstnametextfield.text); 
     } 
     else if(lastnametextfield.text==NULL) { 
      [email protected]"enter last name"; 
      NSLog(@"%@",lastnametextfield.text); 
     } 

     else if(emailtextfield.text==NULL) { 
      [email protected]"enter email address"; 
      NSLog(@"%@",emailtextfield.text); 
     } 

     else if(companytextfield.text==NULL) { 
      [email protected]"enter company name"; 
      NSLog(@"%@",companytextfield.text); 
     } 

     else if(phonetextfield.text==NULL) { 
      [email protected]"enter phone numper"; 
      NSLog(@"%@",phonetextfield.text); 
     } 
    else { 
     [email protected]"register success fully"; 
     UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error" message:msg delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK", nil]; 
     [alert show]; 
     [alert release]; 
    } 

    }

來源

2012-09-04 NANNAV

有一對夫婦的事情要考慮這個代碼：

正如其他人所指出的那樣，這是不檢查一個空字符串的正確方法。
a。首先，如果您確實想要檢查未分配的字符串，則應該檢查nil而不是NULL。 b。其次，字符串也可以被分配，但是沒有字符，所以你應該檢查它是否是空字符串。
c。請注意，您通常希望檢查這兩個條件中的兩個，並且執行相同的操作，因爲通常情況下，就業務邏輯而言，字符串nil與空字符之間沒有區別。 d。最簡單的方法是簡單地檢查字符串的length。這是有效的，因爲如果消息發送到一個nil對象，它將返回0，如果它是一個沒有字符的實際字符串，它也將返回0.

因此，類似於此的檢查將工作而不是：
```
if([firstnametextfield.text length] == 0) 
```
你通常做不要檢查文本字段的值，直接像這樣的表單驗證。這是因爲，在某些情況下（例如當文本字段位於表格視圖單元格中並且滾動屏幕時）文本字段不可用，並且您將無法訪問存儲在文本字段中的數據。

相反，你應該收集它是由文本字段的委託設置爲您的視圖控制器，並實現以下功能進入後文：

- (void)textFieldDidEndEditing:(UITextField *)textField { 
    if (textField == firstnametextfield) { 
     // Store the first name in a property, or array, or something. 
    } 
}

然後，當你準備好要驗證輸入的信息，請使用上面＃1中的技術檢查您存儲的值，而不是實際的文本字段值本身。

來源

2012-09-04 15:02:56 lnafziger

很容易檢查文本提交，感謝您的幫助 – NANNAV

你不應該NULL文本字段值進行比較。相反，將其與@""進行比較。您還可以修剪空白字符太：使用

if([lastnameTextField.text isEqualToString:@""]) 
{ 
msg = @"Enter last name"; 
NSLog(@"%@",lastnametextfield.text); 
}

[string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

來源

2012-09-04 14:24:34 woz

試試這個是你如何檢查是否一個的NSString爲空。

來源

2012-09-04 14:40:25

使用==或！=運算符不能比較字符串對象。所以這裏是正確的：

-(void)sendclick 
{ 
    NSString *msg; 
    if([firstnametextfield.text isEqualToString:@""]) 
    { 
     [email protected]"enter first name"; 
     NSLog(@"%@",firstnametextfield.text); 
    } 
    else 
     if([lastnametextfield.text isEqualToString:@""]) 
    { 
     [email protected]"enter last name"; 
     NSLog(@"%@",lastnametextfield.text); 
    } 

    else if([emailtextfield.text isEqualToString:@""]) 
    { 
     [email protected]"enter email address"; 
     NSLog(@"%@",emailtextfield.text); 
    } 

    else if([companytextfield.text isEqualToString:@""]) 
    { 
     [email protected]"enter company name"; 
     NSLog(@"%@",companytextfield.text); 
    } 

    else if([phonetextfield.text isEqualToString:@""]) 
    { 
     [email protected]"enter phone numper"; 
     NSLog(@"%@",phonetextfield.text); 
    } 
    else 
    { 

    [email protected]"register success fully"; 
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error" message:msg delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK", nil]; 
    [alert show]; 
    [alert release]; 
} 

}

我希望能幫到你。

來源

2012-09-04 14:41:02 hightech

它的工作只是文本字段包含字符串，文本字段將清空它不會進入循環警報給定值，味精= @「充分註冊成功」， – NANNAV

我真的dont't得到這個評論！如果我只是在所有領域的空白？這個驗證會說OK，一切正常，什麼？像@「」這樣的名字？ .... Woz說你應該這樣做[字符串stringByTrimmingCharactersInSet：[NSCharacterSet whitespaceAndNewlineCharacterSet]]; –

- (BOOL)isEmptyOrNull:(NSString*)string { 
    if (string) { 
     if ([string isEqualToString:@""]) { 
      return YES; 
     } 
     return NO; 
    } 
    return YES; 
} 


-(void)sendclick { 
    NSString *msg; 
    if([self isEmptyOrNull:firstnametextfield.text]) { 
     [email protected]"enter first name"; 
     NSLog(@"%@",firstnametextfield.text); 
    } 
    ..... 
    ..... 
    .....

來源

2012-09-04 14:43:26

-(void)sendclick 
    { 
     if ([self ControlValidation]==YES) 
     { 

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Sucess" message:@"Registration done successfully" delegate: nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; 
      [alert show]; 
     } 
    } 
    -(BOOL)ControlValidation 
    { 
     if ([self isEmpty:firstnametextfield.text ]==YES) 

     { 
      UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Sorry" message:@"First Name is empty" delegate: nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; 
      [alert show]; 
      return NO; 
     } 
     if ([self isEmpty:lasttnametextfield.text ]==YES) 

     { 
      UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Sorry" message:@"Last Name is empty" delegate: nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; 
      [alert show]; 

      return NO; 
     } 
     return YES; 
    } 


    -(BOOL)isEmpty:(NSString *)str 

    { 
     if (str == nil || str == (id)[NSNull null] || [[NSString stringWithFormat:@"%@",str] length] == 0 || [[[NSString stringWithFormat:@"%@",str] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] length] == 0) 
     { 
      return YES; 

     } 

     return NO; 
    }

來源

2014-12-24 12:20:09

-(void)validateTextFields 
     { 
      if ([self Validation]==YES) 
      { 

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Sucess" message:@"Registration done successfully" delegate: nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; 
      [alert show]; 
     } 
    } 
    -(BOOL)Validation 
    { 
     if ([self isEmpty:firstnametextfield.text ]==YES) 

    { 
     UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Sorry" message:@"First Name is empty" delegate: nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; 
     [alert show]; 
     return NO; 
    } 
    if ([self isEmpty:lasttnametextfield.text ]==YES) 

    { 
     UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Sorry" message:@"Last Name is empty" delegate: nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; 
     [alert show]; 

     return NO; 
    } 
if ([self isEmpty:Usernametextfield.text ]==YES) 

    { 
     UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Sorry" message:@"First Name is empty" delegate: nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; 
     [alert show]; 
     return NO; 
    } 
    if ([self isEmpty:phonetextfield.text ]==YES) 

    { 
     UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Sorry" message:@"Last Name is empty" delegate: nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; 
     [alert show]; 

     return NO; 
if ([self isEmpty:emailtextfield.text ]==YES) 

    { 
     UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Sorry" message:@"First Name is empty" delegate: nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; 
     [alert show]; 
     return NO; 
    } 
    if ([self isEmpty:passwordtextfield.text ]==YES) 

    { 
     UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Sorry" message:@"Last Name is empty" delegate: nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; 
     [alert show]; 

     return NO; 
    } 
    } 
    return YES; 
} 


-(BOOL)isEmpty:(NSString *)str 

{ 
    if (str == nil || str == (id)[NSNull null] || [[NSString stringWithFormat:@"%@",str] length] == 0 || [[[NSString stringWithFormat:@"%@",str] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] length] == 0) 
    { 
     return YES; 

    }

來源

2016-03-23 11:34:48

@NANNAV ....檢查它與此解決方案 –

驗證多個uitextfield

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