如何從我的UIViewcontroller類調用類別方法？

Question

錯誤

您好我有base64編碼類別，我需要調用的東西從我的主類方法。以下是我的類別

CODE

#import <Foundation/Foundation.h> 

@interface NSString (addition) 
- (NSString *) base64StringFromData:(NSData *)data length:(int)length; 

@end 

在.m文件

#import "NSString+addition.h" 
static char base64EncodingTable[64] = { 
    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 
    'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 
    'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 
    'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' 
}; 

@implementation NSString (addition) 

- (NSString *) base64StringFromData: (NSData *)data length: (int)length { 
    unsigned long ixtext, lentext; 
    long ctremaining; 
    unsigned char input[3], output[4]; 
    short i, charsonline = 0, ctcopy; 
    const unsigned char *raw; 
    NSMutableString *result; 

    lentext = [data length]; 
    if (lentext < 1) 
     return @""; 
    result = [NSMutableString stringWithCapacity: lentext]; 
    raw = [data bytes]; 
    ixtext = 0; 

    while (true) { 
     ctremaining = lentext - ixtext; 
     if (ctremaining <= 0) 
      break; 
     for (i = 0; i < 3; i++) { 
      unsigned long ix = ixtext + i; 
      if (ix < lentext) 
       input[i] = raw[ix]; 
      else 
       input[i] = 0; 
     } 
     output[0] = (input[0] & 0xFC) >> 2; 
     output[1] = ((input[0] & 0x03) << 4) | ((input[1] & 0xF0) >> 4); 
     output[2] = ((input[1] & 0x0F) << 2) | ((input[2] & 0xC0) >> 6); 
     output[3] = input[2] & 0x3F; 
     ctcopy = 4; 
     switch (ctremaining) { 
      case 1: 
       ctcopy = 2; 
       break; 
      case 2: 
       ctcopy = 3; 
       break; 
     } 

     for (i = 0; i < ctcopy; i++) 
      [result appendString: [NSString stringWithFormat: @"%c", base64EncodingTable[output[i]]]]; 

     for (i = ctcopy; i < 4; i++) 
      [result appendString: @"="]; 

     ixtext += 3; 
     charsonline += 4; 

     if ((length > 0) && (charsonline >= length)) 
      charsonline = 0; 
    }  
    return result; 
} 

@end 

我的UIViewController梅索德CODE

我需要從這個方法調用

方法ategory

- (void)completeTransaction:(SKPaymentTransaction *)transaction { 
    NSLog(@"completeTransaction..."); 

    UIAlertView *alert=[[UIAlertView alloc]initWithTitle:@"Alert" message:@"Transaction completed." delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil, nil]; 
    [alert show]; 
    [self provideContentForProductIdentifier:transaction.payment.productIdentifier]; 
    NSLog(@"naveen%@",transaction.transactionReceipt); 

    //CALL CATEGORY METHOD HERE 

    [[SKPaymentQueue defaultQueue] finishTransaction:transaction]; 
} 

Answer 1

NSString *tsr=[NSString base64StringFromData:transaction.transactionReceipt length:[transaction.transactionReceipt length]]; 
    NSLog(@"%@",tsr); 

Answer 2

首次進口的類別到你需要這樣的視圖 - 控制：

#import "NSString+addition.h" 

調用它：

NSString *newString = [myString base64StringFromData:data length:length]; 

只是一個例子。根據您的情況改變它...

您的代碼SHLD這個樣子的：

NSString *tsr = [receiptStr base64StringFromData:transaction.transactionReceipt length:[transaction.transactionReceipt length]]; 

編輯：

您需要添加的類別中的「的NSString + addition.m」下在「項目設置」下的「構建階段」選項卡中編譯源。

Answer 3

首先，你需要導入類別中的UIViewController實現文件

#import "NSString+addition.h" 

在你的方法創建一個新的字符串對象，並調用像所有其他的NSString方法的方法：

- (void)completeTransaction:(SKPaymentTransaction *)transaction 
{ 
    [...] 
    NSString *base64String = [stringToConvert base64StringFromData:dataObject length:length]; 
    [...] 
} 

---

請注意，有些類別的編碼約定：

1. 類別名稱以大寫字母開頭。在你的情況下，你應該將其重命名爲Additions

2. 文件名具有以下格式NameOfClassToAddTheCategoryTo + DescriptiveNameOfNewFunctionality。在你的情況下，它可能是「NSString + Base64」。

---

編輯：由於發佈新的信息，請先閱讀有關Categories蘋果的文檔。

然後更改您base64StringFromData:dataObject:length:方法是一個類方法（What is the difference between class and instance methods?）：

+ (NSString *)base64StringFromData:(NSData *)data length:(int)length 
{ 
    [...] 
    return [result copy]; 
} 

最後，你可以調用

- (void)completeTransaction:(SKPaymentTransaction *)transaction 
{ 
    [...] 
    NSData *receiptData = [transaction transactionReceipt]; 
    int receiptDataLength = [transaction transactionReceipt] length]; 
    NSString *base64String = [NSString base64StringFromData:receiptData length:receiptDataLength]; 
    [...] 
} 

Answer 4

改變方法：

- (NSString *) base64StringFromData: (NSData *)data length: (int)length; 

到：

+ (NSString *) base64StringFromData: (NSData *)data length: (int)length; 

因爲receiptStr沒有啓動。