限制多個UITextFields的長度

Question

我有四個UITextField s，並且想限制每個長度，但它們都是不同的長度。我有以下的代碼，到目前爲止，但它並不完全正常工作

define MAXLENGTH 5 
define MAXQTY 3 
define MAXSIZE 4 
define MAXBRAND 10 

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{ 
    int lengtha = [brand.text length] ; 
    NSLog(@"lenghta = %d",lengtha); 
    if (lengtha >= MAXBRAND && ![string isEqualToString:@""]) { 
    brand.text = [brand.text substringToIndex:MAXBRAND]; 
     return NO; 
    } 
    return YES; 

    int lengthb = [qty.text length] ; 
    NSLog(@"lenghtb = %d",lengtha); 
    if (lengthb >= MAXQTY && ![string isEqualToString:@""]) { 
     qty.text = [qty.text substringToIndex:MAXQTY]; 
     return NO; 
    } 
    return YES; 

    int lengthc = [size.text length] ; 
    NSLog(@"lenghtc = %d",lengtha); 
    if (lengthc >= MAXSIZE && ![string isEqualToString:@""]) { 
     size.text = [size.text substringToIndex:MAXSIZE]; 
     return NO; 
    } 
    return YES; 

    int lengthd = [price.text length] ; 
    NSLog(@"lenghtd = %d",lengtha); 
    if (lengthd >= MAXLENGTH && ![string isEqualToString:@""]) { 
     price.text = [price.text substringToIndex:MAXLENGTH]; 
     return NO; 
    } 
    return YES; 
} 

Answer 1

如果品牌，數量，尺寸和價格都是實例變量（或屬性），並連接到您的UITextFields你可以試試這個：

define MAXLENGTH 5 
define MAXQTY 3 
define MAXSIZE 4 
define MAXBRAND 10 

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{ 
    if (textField == brand) { 
     int lengtha = [brand.text length]; 
     NSLog(@"lenghta = %d",lengtha); 
     if (lengtha >= MAXBRAND && ![string isEqualToString:@""]) { 
      brand.text = [brand.text substringToIndex:MAXBRAND]; 
      return NO; 
     } 
     return YES; 
    } else if (textField == qty) { 
     int lengthb = [qty.text length]; 
     NSLog(@"lenghtb = %d",lengthb); 
     if (lengthb >= MAXQTY && ![string isEqualToString:@""]) { 
      qty.text = [qty.text substringToIndex:MAXQTY]; 
      return NO; 
     } 
     return YES; 
    } else if (textField == size) { 
     int lengthc = [size.text length]; 
     NSLog(@"lenghtc = %d",lengthc); 
     if (lengthc >= MAXSIZE && ![string isEqualToString:@""]) { 
      size.text = [size.text substringToIndex:MAXSIZE]; 
      return NO; 
     } 
     return YES; 
    } else if (textField == price) { 
     int lengthd = [price.text length]; 
     NSLog(@"lenghtd = %d",lengthd); 
     if (lengthd >= MAXLENGTH && ![string isEqualToString:@""]) { 
      price.text = [price.text substringToIndex:MAXLENGTH]; 
      return NO; 
     } 
     return YES; 
    } 
    return YES; 
}