This document provides an overview of using Core Data for mobile applications. It discusses creating a data model, using NSManagedObjectContext to manage objects, UIManagedDocument for document management, generating object model classes, and performing basic CRUD operations. It also covers using NSFetchedResultsController to monitor fetch requests and update table views. An example TaskList app is presented to demonstrate these Core Data concepts.

1. Mobile City: Core Data
TaskList

2. About Me
● Allan Davis
– Lead Developer of Mobile Technology for
DealerMatch
– Cajun.code@gmail.com
– @cajun_code

3. Session Agenda
● Introduction(Tip Calculator)
● Overview of Objective C(TicTacToe)
● UI UX (TrackerPoker)
● CoreData (MyBloodyTaskList)
● Networking and web-services
(TrackerPokerLive)
● Debugging, Testing, Tuning and Distribution
● Game Development with Cocos2d (Oni Attack)

4. Class Agenda
● What is CoreData
● Create the Data Model
● NSManagedObjectContext
● UIManagedDocument
● AppDelegate
● Generate Object Models
● Create
● Read
● Update
● Delete
● NSFetchedResultsController

5. What is Core Data
● Object Relational Management tool.
● How does it work?
– Create a visual mapping of database to objects
– Create query for objects using object-oriented API
– Access the “columns in the database table” using
properties on the objects

6. Creating the Data Model

7. Create Model Visually

8. NSManagedObjectContext
● Session Management object where all activity
turns.
● Two ways to create one.
– Create a UIManagedDocument and ask for the
context
– Property off the AppDelegate if you selected “Use
Core Data” when you created the project

9. UIManagedDocument
● Create Property for UIManagedDocument
- (void)useDocument
{
if (![[NSFileManager defaultManager] fileExistsAtPath:[self.photoDatabase.fileURL path]]) {
// does not exist on disk, so create it
[self.photoDatabase saveToURL:self.photoDatabase.fileURL
forSaveOperation:UIDocumentSaveForCreating completionHandler:^(BOOL success) {
[self setupFetchedResultsController];
[self fetchFlickrDataIntoDocument:self.photoDatabase];
}];
} else if (self.photoDatabase.documentState == UIDocumentStateClosed) {
// exists on disk, but we need to open it
[self.photoDatabase openWithCompletionHandler:^(BOOL success) {
[self setupFetchedResultsController];
}];
} else if (self.photoDatabase.documentState == UIDocumentStateNormal) {
// already open and ready to use
[self setupFetchedResultsController];
}
}

10. AppDelegate
● Generated by Xcode
● Need to push context down to down to
ViewController
UINavigationController *navigationController = (UINavigationController *)self.window.rootViewController;
UIViewController *controller = navigationController.topViewController;
[controller performSelector:@selector(setManagedObjectContext:) withObject:self.managedObjectContext];

11. Generate Classes from Model

12. Create
Trim *trim = [NSEntityDescription insertNewObjectForEntityForName:@"Trim"
inManagedObjectContext:context];

13. Read
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription
entityForName:@"Task" inManagedObjectContext:context];
[fetchRequest setEntity:entity];
fetchRequest.predicate =
[NSPredicate predicateWithFormat:@"category.name = %@", category.name];
fetchRequest.sortDescriptors =
@[[NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES]];
[context executeFetchRequest:fetchRequest error:&error];

14. Update
● Make changes to property
● Call save on the ManagedObjectContext

15. Delete
● Call delete on the ManagedObjectContext and
pass in the object to delete

16. NSFetchRequestController
● Adds functionality to monitor a FetchRequest
to update a table view.

17. TaskList
● Simple Task List
● Sorted by Category

18. Resources
● Stanford CS 193P
– Lecture 13 and 14 are Core Data
– http://www.stanford.edu/class/cs193p/cgi-bin/drupal/
● Class Links
– Videos: http://vimeo.com/channels/mobilecity
– Slides: http://www.slideshare.net/javaalley/
– Code:
https://github.com/organizations/AtlantaMobileDevGroup