我有以下代码可以将我的核心数据与iCloud同步。但是，当我说时，我只想让它同步。例如，仅在wifi上同步。我能做到吗？这是我的代码：
- (NSManagedObjectContext *)managedObjectContext {
if (managedObjectContext != nil) {
return managedObjectContext;
}
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil) {
NSManagedObjectContext* moc = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
[moc performBlockAndWait:^{
[moc setPersistentStoreCoordinator: coordinator];
[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(mergeChangesFrom_iCloud:) name:NSPersistentStoreDidImportUbiquitousContentChangesNotification object:coordinator];
}];
managedObjectContext = moc;
managedObjectContext.mergePolicy = [[NSMergePolicy alloc]
initWithMergeType:NSMergeByPropertyObjectTrumpMergePolicyType];
}
return managedObjectContext;
}
- (void)mergeChangesFrom_iCloud:(NSNotification *)notification {
NSLog(@"Merging in changes from iCloud...");
NSManagedObjectContext* moc = [self managedObjectContext];
[moc performBlock:^{
[moc mergeChangesFromContextDidSaveNotification:notification];
NSNotification* refreshNotification = [NSNotification notificationWithName:@"SomethingChanged"
object:self
userInfo:[notification userInfo]];
[[NSNotificationCenter defaultCenter] postNotification:refreshNotification];
}];
}
- (NSManagedObjectModel *)managedObjectModel {
if (managedObjectModel != nil) {
return managedObjectModel;
}
NSString *modelPath = [[NSBundle mainBundle] pathForResource:@"EntryDatabase" ofType:@"momd"];
NSURL *modelURL = [NSURL fileURLWithPath:modelPath];
managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
return managedObjectModel;
}
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
if((persistentStoreCoordinator != nil)) {
return persistentStoreCoordinator;
}
persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: [self managedObjectModel]];
NSPersistentStoreCoordinator *psc = persistentStoreCoordinator;
// Set up iCloud in another thread:
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// ** Note: if you adapt this code for your own use, you MUST change this variable:
NSString *iCloudEnabledAppID = @"iCloud ID is here, i removed it from stack overflow";
// ** Note: if you adapt this code for your own use, you should change this variable:
NSString *dataFileName = @"CoreDataStore.sqlite";
// ** Note: For basic usage you shouldn't need to change anything else
NSString *iCloudDataDirectoryName = @"Data.nosync";
NSString *iCloudLogsDirectoryName = @"Logs";
NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *storePath = [[self applicationDocumentsDirectory] stringByAppendingPathComponent:dataFileName];
NSURL *localStore = [NSURL fileURLWithPath:storePath];
NSURL *iCloud = [fileManager URLForUbiquityContainerIdentifier:nil];
if (iCloud) {
NSLog(@"iCloud is working");
NSURL *iCloudLogsPath = [NSURL fileURLWithPath:[[iCloud path] stringByAppendingPathComponent:iCloudLogsDirectoryName]];
NSLog(@"iCloudEnabledAppID = %@",iCloudEnabledAppID);
NSLog(@"dataFileName = %@", dataFileName);
NSLog(@"iCloudDataDirectoryName = %@", iCloudDataDirectoryName);
NSLog(@"iCloudLogsDirectoryName = %@", iCloudLogsDirectoryName);
NSLog(@"iCloud = %@", iCloud);
NSLog(@"iCloudLogsPath = %@", iCloudLogsPath);
if([fileManager fileExistsAtPath:[[iCloud path] stringByAppendingPathComponent:iCloudDataDirectoryName]] == NO) {
NSError *fileSystemError;
[fileManager createDirectoryAtPath:[[iCloud path] stringByAppendingPathComponent:iCloudDataDirectoryName]
withIntermediateDirectories:YES
attributes:nil
error:&fileSystemError];
if(fileSystemError != nil) {
NSLog(@"Error creating database directory %@", fileSystemError);
}
}
NSString *iCloudData = [[[iCloud path]
stringByAppendingPathComponent:iCloudDataDirectoryName]
stringByAppendingPathComponent:dataFileName];
NSLog(@"iCloudData = %@", iCloudData);
NSMutableDictionary *options = [NSMutableDictionary dictionary];
[options setObject:[NSNumber numberWithBool:YES] forKey:NSMigratePersistentStoresAutomaticallyOption];
[options setObject:[NSNumber numberWithBool:YES] forKey:NSInferMappingModelAutomaticallyOption];
[options setObject:iCloudEnabledAppID forKey:NSPersistentStoreUbiquitousContentNameKey];
[options setObject:iCloudLogsPath forKey:NSPersistentStoreUbiquitousContentURLKey];
[psc lock];
[psc addPersistentStoreWithType:NSSQLiteStoreType
configuration:nil
URL:[NSURL fileURLWithPath:iCloudData]
options:options
error:nil];
[psc unlock];
}
else {
NSLog(@"iCloud is NOT working - using a local store");
NSMutableDictionary *options = [NSMutableDictionary dictionary];
[options setObject:[NSNumber numberWithBool:YES] forKey:NSMigratePersistentStoresAutomaticallyOption];
[options setObject:[NSNumber numberWithBool:YES] forKey:NSInferMappingModelAutomaticallyOption];
[psc lock];
[psc addPersistentStoreWithType:NSSQLiteStoreType
configuration:nil
URL:localStore
options:options
error:nil];
[psc unlock];
}
dispatch_async(dispatch_get_main_queue(), ^{
[[NSNotificationCenter defaultCenter] postNotificationName:@"SomethingChanged" object:self userInfo:nil];
});
});
return persistentStoreCoordinator;
}
答案 0 :(得分：2)
据我所知，这不可能发生。无论如何，不是以任何简单有效的方式。
问题是iCloud的操作不透明。因此，iOS决定何时会发生同步以及发生频率。在上面的文档中，Apple说“最佳实践”是专门使用沙盒或专门使用iCloud，但不要在它们之间复制数据。
也就是说，当iCloud不可用时，苹果会参考操作。这似乎符合您的建议。从根本上说，您需要正常设置，确保您拥有所需的数据，然后停用iCloud并将数据移动到沙箱中进行处理。如果要同步，只需将数据复制回来。
要处理iCloud可用性的更改，请实现在接收NSUbiquityIdentityDidChangeNotification通知时调用的方法。您的方法需要执行以下工作：
调用ubiquityIdentityToken方法并存储其返回值。 将新值与之前的值进行比较，以确定用户是否已退出帐户或登录其他帐户。 如果以前使用的帐户现在不可用，请根据需要在本地保存当前状态，清空与iCloud相关的数据缓存，并刷新所有与iCloud相关的用户界面元素。 如果您希望允许用户继续创建iCloud不可用的内容，请将该内容存储在应用程序的沙箱容器中。当帐户再次可用时，将新内容移至iCloud。通常最好不要通知用户或要求用户进行任何交互。
这似乎符合您的要求。但是，我自己才刚刚到达这个阶段，所以我不能进一步评论。