NSURLIsExcludedFromBackupKey无法正确设置 [英] NSURLIsExcludedFromBackupKey can not be set correctly

问题描述

我正在尝试阻止整个文件夹由itunes备份。我按照技术报告 http://developer.apple.com/library /ios/#qa/qa1719/_index.html 但似乎falg每次都是零。我在模拟器和设备上使用IOS 5.1。但没有任何帮助。该方法返回 成功 每一次，但标志仍是零

  +（BOOL）hasSkipBackupAttributeToItemAtURL：（NSURL *）网址
 {
 NSError * error = nil; 
 
 id flag = nil; 
 BOOL success = [URL getResourceValue：& flag 
 forKey：NSURLIsExcludedFromBackupKey error：& error]; 
 
 if（！success）{
 
 NSLog（@错误排除％@来自备份％@，[URL lastPathComponent]，错误）; 
返回false; 
} 
 
 if（！flag）
返回false; 
 
 return [flag boolValue]; 
} 
 
 +（BOOL）addSkipBackupAttributeToItemAtURL：（NSURL *）URL 
 {
 NSError * error = nil; 
 
 BOOL成功= [URL setResourceValue：[NSNumber的numberWithBool：YES] 
 forKey：NSURLIsExcludedFromBackupKey误差：&安培;错误]; 
 
 if（！success）{
 
 NSLog（@错误排除％@来自备份％@，[URL lastPathComponent]，错误）; 
 
} 
 
返回成功; 
 
} 
 
 +（BOOL）removeSkipBackupAttributeToItemAtURL：（NSURL *）URL 
 {
 NSError * error = nil; 
 
 BOOL success = [URL setResourceValue：[NSNumber numberWithBool：NO] 
 forKey：NSURLIsExcludedFromBackupKey错误：& error]; 
 
 if（！success）{
 
 NSLog（@错误排除％@来自备份％@，[URL lastPathComponent]，错误）; 
 
} 
 
返回成功; 
 
} 
  

解决方案

我只是修复此问题在我的应用程序中虽然有点令人沮丧，但它最终都工作得很好。
所以，这是 addSkipBackupAttributeToItemAtURL 的代码。你可能想检查一下。它也对待5.0.1和5.0。您只需在代码中处理5.1及更高版本。

但

假设您有一个NSString *路径 - 文件/文件夹的路径，不要使用调用方法：

[NSURL urlWithString：path]; 它适用于5.0.1但不适用于5.1及更高版本。

相反用[NSURL fileURLWithPath：路径];

所以：的 [MyClass的addSkipBackupAttributeToItemAtURL： NSURL fileURLWithPath：path]];

事实上，我认为这是您代码的唯一问题。采用我链接的方法，只会提供向后兼容性，这是一个很好的补充。

希望这会有所帮助。

问候，
George

I am trying to prevent a whole folder from beeing backed up by itunes. I followed the Technical Report http://developer.apple.com/library/ios/#qa/qa1719/_index.html But it seems that falg is everytime nil. I use IOS 5.1 tried in in simulator and on device. But nothing helps. The methods return "success" every time, but flag is still nil.

+ (BOOL) hasSkipBackupAttributeToItemAtURL:(NSURL *)URL
{
    NSError *error = nil;

    id flag = nil;
    BOOL success = [URL getResourceValue: &flag
                                  forKey: NSURLIsExcludedFromBackupKey error: &error];

    if(!success){

        NSLog(@"Error excluding %@ from backup %@", [URL lastPathComponent], error);
        return false;
    }

    if (!flag)
        return false;

    return [flag boolValue];
}

+ (BOOL)addSkipBackupAttributeToItemAtURL:(NSURL *)URL
{
    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;

}

+ (BOOL)removeSkipBackupAttributeToItemAtURL:(NSURL *)URL
{
    NSError *error = nil;

    BOOL success = [URL setResourceValue: [NSNumber numberWithBool: NO]
                                  forKey: NSURLIsExcludedFromBackupKey error: &error];

    if(!success){

        NSLog(@"Error excluding %@ from backup %@", [URL lastPathComponent], error);

    }

    return success;

}

解决方案

I just fixed this in my app and while it was kind of frustrating , it all ended up working great. So , here's the code for the addSkipBackupAttributeToItemAtURL . You may want to check that out. It treats 5.0.1 and 5.0 too. You are only treating 5.1 and higher in your code.

BUT:

Let's say you have an NSString *path - the path to your file /folder , don't call the method with:

[NSURL urlWithString:path]; It will work on 5.0.1 but not on 5.1 and higher.

Instead use [NSURL fileURLWithPath:path];

So: [MyClass addSkipBackupAttributeToItemAtURL:[NSURL fileURLWithPath:path]];

In fact , I think that is the only problem with your code. Taking the method I linked to , will only provide backward compatibility , which is a great addition.

Hope this helps.

Regards, George

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