我刚刚使用新的iOS 13 NSPersistentCloudKitContainer
完成CoreData + CloudKit的设置。它可以很好地工作,因为我可以使用自动生成的CoreData类进行属性访问和本地存储,并且NSPersistentCloudKitContainer
自动在设备之间同步更改。我遇到的问题是如何获得有关远程更改的通知。我已经检查了Apple文档,并声明您告诉NSPersistentCloudKitContainer
的NSPersistentStoreDescription
您要它发送通知,然后将其他对象注册为该通知的观察者。我已完成此操作,并添加了一种测试方法来显示何时检测到远程更改。测试方法生成的警报永远不会生成,但是如果我终止了该应用程序并重新打开它,则更改将立即存在。因此,我认为远程更改已同步并集成到本地CoreData存储中,但是通知无法正常工作。我已将Background Modes
授权添加到目标中,并选择了Remote notification
模式。代码如下。任何帮助将不胜感激!
[设置发送通知的选项:
- (NSPersistentCloudKitContainer *)persistentContainer {
// The persistent container for the application. This implementation creates and returns a container, having loaded the store for the application to it.
@synchronized (self) {
if (_persistentContainer == nil) {
_persistentContainer = [[NSPersistentCloudKitContainer alloc] initWithName:@"<redacted>"];
[_persistentContainer loadPersistentStoresWithCompletionHandler:^(NSPersistentStoreDescription *storeDescription, NSError *error) {
if (error != nil) {
// ...
}
else {
// ...
[storeDescription setOption:@(YES) forKey:NSPersistentStoreRemoteChangeNotificationPostOptionKey];
// ...
}
}];
}
}
return _persistentContainer;
}
正在注册接收通知:
- (void)viewDidLoad {
[super viewDidLoad];
// ...
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(changes) name:NSPersistentStoreRemoteChangeNotification object:[CoreDataFunctions persistentContainer]];
}
测试方法以响应更改:
- (void)changes {
UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Changes received" message:nil preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction *ok = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:nil];
[alert addAction:ok];
[self presentViewController:alert animated:YES completion:nil];
}
[访问应用程序的持久性CloudKit容器以获取viewContext
时,您需要将automaticallyMergesChangesFromParent
属性设置为true
。
lazy var managedContext: NSManagedObjectContext = {
self.storeContainer.viewContext.automaticallyMergesChangesFromParent = true
return self.storeContainer.viewContext
}()
进行单行更改将使应用程序(NSFetchedResultsController
支持)可以响应于远程数据更改而更新UI ...