iOS避免文件被同步到iCloud或iTunes

在沙盒创建一个文件

 - (void)createSkipBackupImagesFolder {
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *dataPath = [documentsDirectory stringByAppendingPathComponent:@"/images"];

    NSError *error;
    if (![[NSFileManager defaultManager] fileExistsAtPath:dataPath]) {
        [[NSFileManager defaultManager] createDirectoryAtPath:dataPath withIntermediateDirectories:NO attributes:nil error:&error];
        NSURL *toURL = [NSURL fileURLWithPath:dataPath];
        [self addSkipBackupAttributeToItemAtURL:toURL];
    }
}

避免该文件被同步到iCloud或iTunes，使用NSURLIsExcludedFromBackupKey    

- (BOOL)addSkipBackupAttributeToItemAtPath:(NSString *) filePathString
    {
    NSURL* URL= [NSURL fileURLWithPath: filePathString];
    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;
}

参考链接：https://developer.apple.com/library/ios/qa/qa1719/_index.html#//apple_ref/doc/uid/DTS40011342

http://stackoverflow.com/questions/12971192/how-should-i-prevent-files-from-being-backed-up-to-icloud-and-itunes-on-ios-5-0