Core Data Stack有下面的四个类组成:
NSManagedObjectModelNSPersistentStoreNSPersistentStoreCoordinatorNSManagedObjectContext
实现自己的Core Data Stack
class CoreDataStack {
let modelName = "Dog Walk"
private lazy var applicationDocumentsDirectory: NSURL = {
//返回一个[NSURL]
let urls = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)
print(urls.count)
return urls[urls.count - 1]
}()
lazy var context:NSManagedObjectContext = {
//一个在主队列中使用的上下文
var manageObjectContext = NSManagedObjectContext(concurrencyType: .MainQueueConcurrencyType)
//一个持续存储协调器
manageObjectContext.persistentStoreCoordinator = self.psc
return manageObjectContext
}()
private lazy var psc: NSPersistentStoreCoordinator = {
let coordinator: NSPersistentStoreCoordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent(self.modelName)
do {
let options = [NSMigratePersistentStoresAutomaticallyOption : true]
try coordinator.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: options)
} catch {
}
return coordinator
}()
private lazy var managedObjectModel: NSManagedObjectModel = {
let modelURL = NSBundle.mainBundle().URLForResource(self.modelName, withExtension: "momd")!
return NSManagedObjectModel(contentsOfURL: modelURL)!
}()
func saveContext() {
if context.hasChanges {
do {
try context.save()
} catch {
print("Eror")
abort()
}
}
}
}```
