1.首先在Appdelegate.m的- (void)applicationWillTerminate:(UIApplication *)application;中调用下保存的方法.- (void)applicationWillTerminate:(UIApplication *)application {// Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
    [self saveContext];
}2.然后实现通道类和保存的方法.#pragma mark - Core Data stack@synthesize persistentContainer = _persistentContainer;- (NSPersistentContainer *)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 = [[NSPersistentContainer alloc] initWithName:@"LotterSelectCoreData"];[_persistentContainer loadPersistentStoresWithCompletionHandler:^(NSPersistentStoreDescription *storeDescription, NSError *error) {if (error != nil) {// Replace this implementation with code to handle the error appropriately.// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development./*Typical reasons for an error here include:* The parent directory does not exist, cannot be created, or disallows writing.* The persistent store is not accessible, due to permissions or data protection when the device is locked.* The device is out of space.* The store could not be migrated to the current model version.Check the error message to determine what the actual problem was.*/NSLog(@"Unresolved error %@, %@", error, error.userInfo);abort();}}];}}return _persistentContainer;
}#pragma mark - Core Data Saving support- (void)saveContext {NSManagedObjectContext *context = self.persistentContainer.viewContext;NSError *error = nil;if ([context hasChanges] && ![context save:&error]) {// Replace this implementation with code to handle the error appropriately.// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.NSLog(@"Unresolved error %@, %@", error, error.userInfo);abort();}
}