iOS 5.1 没有备份标志？

Question

由于数据存储指南中的一些问题，我的第一个音乐下载应用程序被拒绝。我试图将我的 mp3 文件保存在 NSDocumentDirectory 中。我需要通过添加标记“不备份”来重新提交我的应用程序。

这是我的代码，

  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");
              }
      }

此代码是否适用于我的 5.1 版本？有点迷茫

Answer 1

参考以下代码。

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;
}