我正在使用NSUbiquitousKeyValueStore存储一些应用程序设置。我的逻辑是:当我在本地保存数据时，我也将其保存为NSUbiquitousKeyValueStore作为备份。当我需要设置时，我会在本地阅读，并且仅在本地未找到数据的情况下才使用iCloud键值存储(例如，在重新安装应用程序之后)。如果用户有多台设备共享一个icloud id，则他可以在一个设备上写入设置并将其下载到另一台设备(我警告他重写)。
我有一个奇怪的问题。脚步:

class CloudHelper
{
public:
    static bool init();
    static void deInit();
    //save our data to iCloud with
    static int saveData(unsigned char* data, int from, int count);
    //get our data from iCloud
    static unsigned char * loadData(int *retsize, int * retint);
    //does iCloud work for us
    static bool isEnabled();
    //do we have our key in iCloud
    static int isAvailable();

    static const int RESULT_OK = 0;
    static const int RESULT_NO_CONNECTION = 1;
    static const int RESULT_NOT_FOUND = 2;
    static const int RESULT_SYNC_ERROR = 3;
private:
    static bool enabled;
    static NSURL *ubiq;
};



bool CloudHelper::enabled = false;

NSURL *CloudHelper::ubiq = NULL;

#define MY_DATA_KEY @"my_data_key"

int CloudHelper::saveData(unsigned char* data, int from, int count)
{
    if ([NSUbiquitousKeyValueStore defaultStore])
    {
        NSData *d = [[[NSData alloc] initWithBytes:(data + from) length:count] autorelease];
        [[NSUbiquitousKeyValueStore defaultStore] setData:d forKey: MY_DATA_KEY)];
        if ([[NSUbiquitousKeyValueStore defaultStore] synchronize] != TRUE)
            return RESULT_SYNC_ERROR;
        return RESULT_OK;
    }
    return RESULT_NO_CONNECTION;
}

unsigned char * CloudHelper::loadData(int *retsize, int * retint)
{
    if ([NSUbiquitousKeyValueStore defaultStore])
    {
        [[NSUbiquitousKeyValueStore defaultStore] synchronize];
        NSData *d = [[NSUbiquitousKeyValueStore defaultStore] dataForKey: MY_DATA_KEY];
        if (d != NULL)
        {
            if (retsize != NULL)
                *retsize = d.length;
            if (retint != NULL)
                *retint = RESULT_OK;
            return d.bytes;
        }
        else
        {
            if (retsize != NULL)
                *retsize = -1;
            if (retint != NULL)
                *retint = RESULT_NOT_FOUND;
        }
    }
    else
    {
        if (retsize != NULL)
            *retsize = -1;
        if (retint != NULL)
            *retint = RESULT_NO_CONNECTION;
    }
    return NULL;
}

int CloudHelper::isAvailable()
{
    int result = RESULT_NO_CONNECTION;

    if ([NSUbiquitousKeyValueStore defaultStore])
    {
        [[NSUbiquitousKeyValueStore defaultStore] synchronize];
        NSData *d = [[NSUbiquitousKeyValueStore defaultStore] dataForKey: MY_DATA_KEY];
        if (d != NULL)
            result = RESULT_OK;
        else
            result = RESULT_NOT_FOUND;
    }
    else
        result = RESULT_NO_CONNECTION;

    return result;
}

void CloudHelper::deInit()
{
    enabled = false;
    [ubiq release];
}

bool CloudHelper::init()
{
    enabled = false;
    NSURL *ubiq_ = [[NSFileManager defaultManager] URLForUbiquityContainerIdentifier:nil];
    [[NSUbiquitousKeyValueStore defaultStore] synchronize];
    if (ubiq)
    {
        enabled = true;
        ubiq = [ubiq_ retain]; //save for further use
    }
    else
    {
        //is implemented elsewhere: this writes a local file with a counter, and if it is < REMINDER_COUNT allows us to show a warning to users
        bool allow = MySystem::isAllowToShowDialog();
        if (allow)
        {
            //determines network state with Apple's Reachability
            if (!MySystem::isNetworkAvailable())
                MySystem::showMessageBox(@"Network error"); //No network
            else
                MySystem::showMessageBox(@"You should log into your iCloud account to be able to backup your settings."); //No login
        }
    }
    return enabled;
}

最佳答案

结论

临时解决方案是:
-在从键值存储中获取数据之前调用同步
-确保它可以正常工作“关闭iCloud-> Documents＆Data-关闭并再次在网络上-开启Documents＆Data”，但是您还应该等待几分钟，然后iCloud才下载所有需要的数据

注意:在安装应用程序并已将其与键值存储一起使用(保存/加载)时，iCloud数据更新非常快(7-15秒)，但是重新安装该应用程序时，icloud似乎需要几分钟才能实现 key -值存储。

我很高兴听到您的想法，因为icloud看起来几乎是无法使用的功能。但是我不想设置自己的服务器仅获得相同的功能。

关于iphone - iCloud NSUbiquitousKeyValueStore初始同步/访问延迟-如何处理？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/12539266/