为什么我的NSUserDefaults实现在ios4下不能工作?

NSUserDefaults 在iphoneos/iossdk中,但我似乎无法让自己的实现正常工作。

然而, 有不同的想法。有人知道为什么我的首选加载方法不断返回吗 (null) NSLog ?

提前谢谢!:)

对视图控制器.m (节略)

- (void)viewDidLoad {

// yadda yadda yadda interface setup here...

    if ([self retrieveCount] == 0) {
        count = 0;
    } else {
        count = [self retrieveCount];
        NSString *temp = [[NSString alloc] initWithFormat:@"%@", count];
        [label setText:temp];
        [temp release];
    }


    [super viewDidLoad];
}

int count = 123; //whatever it might be when the user exits the application, set every time the "+" or "-" is tapped

- (void)writeCount {
    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

    [prefs setInteger:count forKey:@"countKey"];
    [prefs synchronize];

}

- (int)retrieveCount {
    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

    [prefs synchronize];
    int loaded = [prefs integerForKey:@"countKey"];
    NSLog(@"%@", loaded);
    return loaded;
}

- (void)applicationWillTerminate:(UIApplication *)application {
    /*
     Called when the application is about to terminate.
     See also applicationDidEnterBackground:.
     */
    [CountrViewController writeCount];
}

(因为我将只从一个键中检索一个值,所以我决定不对该方法进行任何输入。)

如果这是任何混乱的方式,请让我知道!我很乐意澄清。