不要为iOS 5.1备份标志？

Question

我的第一个音乐下载应用因数据存储指南中的某些问题而被拒绝。我试图将我的mp3文件保存在NSDocumentDirectory中。我需要通过添加标志“不备份”重新提交我的应用程序。

这里是我的代码，

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 



    NSString *documentsDirectoryPath = [[paths objectAtIndex:0]stringByAppendingPathComponent:@"Music.mp3"]; 
    [receivedData writeToFile:documentsDirectoryPath atomically:YES]; 
    [self addSkipBackupAttributeToItemAtURL:downloadURL]; 



- (BOOL)addSkipBackupAttributeToItemAtURL:(NSURL *)URL1 
     { 
      if (&NSURLIsExcludedFromBackupKey == nil) { // iOS <= 5.0.1 
      const char* filePath = [[URL1 path] fileSystemRepresentation]; 

      const char* attrName = "com.apple.MobileBackup"; 
      u_int8_t attrValue = 1; 

      int result = setxattr(filePath, attrName, &attrValue, sizeof(attrValue), 0, 0); 
      return result == 0; 
    } 
      else { // iOS >= 5.1 
        NSError *error = nil; 
        [URL1 setResourceValue:[NSNumber numberWithBool:YES] forKey:NSURLIsExcludedFromBackupKey error:&error]; 

        return error == nil; 
        NSLog(@"success"); 
       } 
     } 

将这个代码工作罚款我的5.1版本？有点困惑

Answer 1

引用下面的代码。

How do I prevent files from being backed up to iCloud and iTunes?

iOS 5.1 and later

- (BOOL)addSkipBackupAttributeToItemAtURL:(NSURL *)URL 
{ 
    assert([[NSFileManager defaultManager] fileExistsAtPath: [URL path]]); 

    NSError *error = nil; 
    BOOL success = [URL setResourceValue: [NSNumber numberWithBool: YES] 
            forKey: NSURLIsExcludedFromBackupKey error: &error]; 
    if(!success){ 
     NSLog(@"Error excluding %@ from backup %@", [URL lastPathComponent], error); 
    } 
    return success; 
} 

in iOS 5.0.1

#import <sys/xattr.h> 
- (BOOL)addSkipBackupAttributeToItemAtURL:(NSURL *)URL 
{ 
    assert([[NSFileManager defaultManager] fileExistsAtPath: [URL path]]); 

    const char* filePath = [[URL path] fileSystemRepresentation]; 

    const char* attrName = "com.apple.MobileBackup"; 
    u_int8_t attrValue = 1; 

    int result = setxattr(filePath, attrName, &attrValue, sizeof(attrValue), 0, 0); 
    return result == 0; 
}