Xcode 6 iOS 8 iCloud core data setup

by

iOS 8 Solution:

OK…then….lol. I think I solved it.

New discovery. After skimming through this page:

http://www.tuaw.com/2014/09/17/psa-do-not-upgrade-to-icloud-drive-during-ios-8-installation/

It says:

iCloud Drive is Apple’s new and improved iCloud syncing and file
storage feature that allows you to share documents between your iOS 8
devices and your Mac running OS X 10 Yosemite.

So, I decided to bite the bullet and upgrade my iCloud account to iCloud drive (free to upgrade).

After upgrading to iCloud drive, and re-ran my app with a few Xcode 6 changes, it’s working now.

Some Important Things to note:

  • iCloud Drive is incompatible with previous iCloud Document & Data storage. So if you’re going to test, make sure all your devices are using iCloud drive and iOS 8.
  • Simulator only seems to sync once, after launching app while device continuously syncs every interval. Not sure if it’s a simulator bug or not. Or maybe my configuration is not perfect.
  • Using “Use default containers” doesn’t work in the simulator for me (but on the device it does work) on the first try, maybe need to delete the previous copy of the app and reinstall. Try using default containers first and see if it works, otherwise, read the next point below.

  • For the above reason, I changed to using a Ubiquity container with this pattern:

    iCloud.$(CFBundleIdentifier)

So something like:

iCloud.com.xxxxxxxx.iCloudCoreDataDemo

Where “xxxxxxxx” is my company name identifier.

I made the above iCloud container by logging into my iOS Developer Center, perhaps you could just press the “+” sign inside Xcode 6 and enter one there, Xcode should automagically setup everything for you.

One block of code I used to test to see if it’s working is this:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    self.persistentStack = [[PersistentStack alloc] initWithStoreURL:self.storeURL modelURL:self.modelURL];
    self.managedObjectContext = self.persistentStack.managedObjectContext;

    NSURL *containerURL = [[NSFileManager defaultManager] URLForUbiquityContainerIdentifier:@"iCloud.com.xxxxxxxxxx.iCloudCoreDataDemo"];

    if(containerURL == nil)
    {
        NSLog(@"containerURL == nil");
    }
    else
    {
        NSLog(@"hurray?");
    }

    return YES;
}

If you see “hurray?” then it’s fine, you should also see this pattern of text in your Xcode console output:

2014-10-07 17:37:23.196 iCloudCoreDataDemo[8104:130250] documentsDirectory = file:///Users/xxxxxxxx/Library/Developer/CoreSimulator/Devices/9FAFE881-13CA-4608-8BE6-728C793FAFFB/data/Containers/Data/Application/BC6CA07D-605A-4927-94AF-E9E21E204D2B/Documents/
2014-10-07 17:37:23.386 iCloudCoreDataDemo[8104:130250] storeDidChange
2014-10-07 17:37:23.390 iCloudCoreDataDemo[8104:130250] -[PFUbiquitySwitchboardEntryMetadata setUseLocalStorage:](808): CoreData: Ubiquity:  nobody~sim301AE3E8-16B2-5A08-917D-7B55D1879BE4:iCloudStore
Using local storage: 1
2014-10-07 17:37:23.402 iCloudCoreDataDemo[8104:130250] hurray?
2014-10-07 17:37:33.909 iCloudCoreDataDemo[8104:130250] storeWillChange
2014-10-07 17:37:33.933 iCloudCoreDataDemo[8104:130250] storeDidChange
2014-10-07 17:37:33.933 iCloudCoreDataDemo[8104:130330] -[PFUbiquitySwitchboardEntryMetadata setUseLocalStorage:](808): CoreData: Ubiquity:  nobody~sim301AE3E8-16B2-5A08-917D-7B55D1879BE4:iCloudStore
Using local storage: 0

Notice the two important lines:

Using local storage: 1

later becomes:

Using local storage: 0

Local storage 1 means it’s currently using local storage, while local storage 0 means it has moved the data to iCloud storage.

I hope this benefits everyone else.

iOS 7 Only Solution:

OK, so I’ve just discovered something and managed to get it working for iOS 7 only. I still haven’t figured out how to do it in iOS 8 but I have noticed something important.

On my iPhone 5 running iOS 8.0.2, I don’t have the “Document & Data” option inside the iCloud settings menu anymore.

However, on my iPad running iOS 7, I DO see the “Document & Data” options.

Perhaps this is the reason why it doesn’t work on iOS 8, we no longer have Document & Data storage ?

Anyhow, here’s what I discovered for iOS 7 only solution.

I found this page here

https://developer.apple.com/library/ios/documentation/General/Conceptual/iCloudDesignGuide/Chapters/iCloudFundametals.html

and one of the line says:

  • iCloud document storage is for user-visible file-based content, Core Data storage, or for other complex file-based content.

Sure enough, I went into my Xcode 6 project file and ticked the “iCloud Documents” option. This un-greyed the radio buttons, but I still left it at “Use default Containers”.

One thing I learned is that I need to init my PersistentStack in the appDelegate. Previously, I tried to init the persistent stack inside the +(id)sharedInstance method but it caused the iCloud to only sync the first time, so after initial load and sync, adding new record doesn’t get synced afterwards.

I rewrote a basic app and modified the persistent stack slightly:

App Delegate.h

#import <UIKit/UIKit.h>
#import "PersistentStack.h"

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@property (nonatomic, strong) NSManagedObjectContext* managedObjectContext;
@property (nonatomic, strong) PersistentStack* persistentStack;


@end

App Delegate.m

@interface AppDelegate ()

@end

@implementation AppDelegate


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    self.persistentStack = [[PersistentStack alloc] initWithStoreURL:self.storeURL modelURL:self.modelURL];
    self.managedObjectContext = self.persistentStack.managedObjectContext;

    return YES;
}

...

- (NSURL*)storeURL
{
    NSURL* documentsDirectory = [[NSFileManager defaultManager] URLForDirectory:NSDocumentDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:YES error:NULL];
    return [documentsDirectory URLByAppendingPathComponent:@"MyApp.sqlite"];
}

- (NSURL*)modelURL
{
    return [[NSBundle mainBundle] URLForResource:@"MyApp" withExtension:@"momd"];
}

Persistent Stack.h

#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>

#import "Book.h"
#import <UIKit/UIKit.h>

@interface PersistentStack : NSObject

+(id)sharedInstance;

- (id)initWithStoreURL:(NSURL *)storeURL modelURL:(NSURL *)modelURL;

@property (nonatomic,strong,readonly) NSManagedObjectContext *managedObjectContext;

#pragma mark - Regular Methods -

-(Book *)insertNewBookWithDate:(NSDate *)newDate;
-(void)deleteBook:(Book *)book;
-(NSArray *)fetchEntityOfType:(NSString *)entityType withPredicate:(NSPredicate *)predicate andSortKey:(NSString *)sortKey;

@end

Persistent Stack.m

#import "PersistentStack.h"
#import "AppDelegate.h"

@interface PersistentStack ()

@property (nonatomic,strong,readwrite) NSManagedObjectContext* managedObjectContext;
@property (nonatomic,strong) NSURL* modelURL;
@property (nonatomic,strong) NSURL* storeURL;

@end

@implementation PersistentStack

+(id)sharedInstance
{
    static PersistentStack *sharedInstance = nil;

    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{

        AppDelegate *appDelegate = (AppDelegate *)[UIApplication sharedApplication].delegate;

        sharedInstance = appDelegate.persistentStack;
    });

    return sharedInstance;
}

- (id)initWithStoreURL:(NSURL*)storeURL modelURL:(NSURL*)modelURL
{
    self = [super init];
    if (self) {
        self.storeURL = storeURL;
        self.modelURL = modelURL;
        [self setupManagedObjectContext];
    }
    return self;
}

- (void)setupManagedObjectContext
{
    self.managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
    self.managedObjectContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy;
    self.managedObjectContext.persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:self.managedObjectModel];


    //__weak NSPersistentStoreCoordinator *psc = self.managedObjectContext.persistentStoreCoordinator;

    // iCloud notification subscriptions
    NSNotificationCenter *dc = [NSNotificationCenter defaultCenter];
    [dc addObserver:self
           selector:@selector(storesWillChange:)
               name:NSPersistentStoreCoordinatorStoresWillChangeNotification
             object:self.managedObjectContext.persistentStoreCoordinator];

    [dc addObserver:self
           selector:@selector(storesDidChange:)
               name:NSPersistentStoreCoordinatorStoresDidChangeNotification
             object:self.managedObjectContext.persistentStoreCoordinator];

    [dc addObserver:self
           selector:@selector(persistentStoreDidImportUbiquitousContentChanges:)
               name:NSPersistentStoreDidImportUbiquitousContentChangesNotification
             object:self.managedObjectContext.persistentStoreCoordinator];

    NSError* error;
    // the only difference in this call that makes the store an iCloud enabled store
    // is the NSPersistentStoreUbiquitousContentNameKey in options. I use "iCloudStore"
    // but you can use what you like. For a non-iCloud enabled store, I pass "nil" for options.

    // Note that the store URL is the same regardless of whether you're using iCloud or not.
    // If you create a non-iCloud enabled store, it will be created in the App's Documents directory.
    // An iCloud enabled store will be created below a directory called CoreDataUbiquitySupport
    // in your App's Documents directory
    [self.managedObjectContext.persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType
                                                                       configuration:nil
                                                                                 URL:self.storeURL
                                                                             options:@{ NSPersistentStoreUbiquitousContentNameKey : @"iCloudStore" }
                                                                               error:&error];
    if (error) {
        NSLog(@"error: %@", error);
    }
}

- (NSManagedObjectModel*)managedObjectModel
{
    return [[NSManagedObjectModel alloc] initWithContentsOfURL:self.modelURL];
}

// Subscribe to NSPersistentStoreDidImportUbiquitousContentChangesNotification
- (void)persistentStoreDidImportUbiquitousContentChanges:(NSNotification*)note
{
    NSLog(@"%s", __PRETTY_FUNCTION__);
    NSLog(@"%@", note.userInfo.description);

    NSManagedObjectContext *moc = self.managedObjectContext;
    [moc performBlock:^{
        [moc mergeChangesFromContextDidSaveNotification:note];

        [[NSNotificationCenter defaultCenter] postNotificationName:@"notifiCloudStoreDidChange" object:nil];

        /*
        // you may want to post a notification here so that which ever part of your app
        // needs to can react appropriately to what was merged.
        // An exmaple of how to iterate over what was merged follows, although I wouldn't
        // recommend doing it here. Better handle it in a delegate or use notifications.
        // Note that the notification contains NSManagedObjectIDs
        // and not NSManagedObjects.
        NSDictionary *changes = note.userInfo;
        NSMutableSet *allChanges = [NSMutableSet new];
        [allChanges unionSet:changes[NSInsertedObjectsKey]];
        [allChanges unionSet:changes[NSUpdatedObjectsKey]];
        [allChanges unionSet:changes[NSDeletedObjectsKey]];

        for (NSManagedObjectID *objID in allChanges) {
            // do whatever you need to with the NSManagedObjectID
            // you can retrieve the object from with [moc objectWithID:objID]
        }
         */

    }];
}

// Subscribe to NSPersistentStoreCoordinatorStoresWillChangeNotification
// most likely to be called if the user enables / disables iCloud
// (either globally, or just for your app) or if the user changes
// iCloud accounts.
- (void)storesWillChange:(NSNotification *)note {

    NSLog(@"storeWillChange");

    NSManagedObjectContext *moc = self.managedObjectContext;

    //[moc performBlockAndWait:^{
    [moc performBlock:^{
        NSError *error = nil;
        if ([moc hasChanges]) {
            [moc save:&error];
        }

        [moc reset];
    }];

    // now reset your UI to be prepared for a totally different
    // set of data (eg, popToRootViewControllerAnimated:)
    // but don't load any new data yet.
}

// Subscribe to NSPersistentStoreCoordinatorStoresDidChangeNotification
- (void)storesDidChange:(NSNotification *)note {
    // here is when you can refresh your UI and
    // load new data from the new store

    NSLog(@"storeDidChange");

    [[NSNotificationCenter defaultCenter] postNotificationName:@"notifiCloudStoreDidChange" object:nil];
}

#pragma mark - Regular Methods -

-(Book *)insertNewBookWithDate:(NSDate *)newDate
{
    Book *newBook = [NSEntityDescription insertNewObjectForEntityForName:@"Book" inManagedObjectContext:self.managedObjectContext];

    newBook.bookName = @"Book";
    newBook.publishDate = newDate;

    [self.managedObjectContext save:nil];

    return newBook;
}

-(void)deleteBook:(Book *)book
{
    [self.managedObjectContext deleteObject:book];

    [self.managedObjectContext save:nil];
}

-(NSArray *)fetchEntityOfType:(NSString *)entityType withPredicate:(NSPredicate *)predicate andSortKey:(NSString *)sortKey
{
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:entityType inManagedObjectContext:self.managedObjectContext];
    [fetchRequest setEntity:entity];
    // Specify criteria for filtering which objects to fetch
    [fetchRequest setPredicate:predicate];
    // Specify how the fetched objects should be sorted
    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:sortKey
                                                                   ascending:YES];
    [fetchRequest setSortDescriptors:[NSArray arrayWithObjects:sortDescriptor, nil]];

    NSError *error = nil;
    NSArray *fetchedObjects = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];

    if (fetchedObjects == nil)
    {
        NSLog(@"couldn't fetch entity of type '%@', error: %@", entityType, error.localizedDescription);
    }

    return fetchedObjects;
}

@end

Leave a Comment

tech