Core Data sorting (1): coredata sorting

Core Data sorting (1): coredata sorting
Sorting Core Data (1)

In Xcode7.2, only the Use Core Data option can be selected in Mast-Debug and Single View.

If you select Use Core Data, Xcode will automatically generate the Core code of Core Data in AppDelegate and automatically generate .xcdatamodeldData Files

1 // Appdelegate. in h, 2 # import <UIKit/UIKit. h> 3 # import <CoreData/CoreData. h> 4 5 @ interface AppDelegate: UIResponder <UIApplicationDelegate> 6 7 @ property (strong, nonatomic) UIWindow * window; 8 9 @ property (readonly, strong, nonatomic) implements * managedObjectContext; 10 @ property (readonly, strong, nonatomic) NSManagedObjectModel * managedObjectModel; 11 @ property (readonly, strong, Nonatomic) NSPersistentStoreCoordinator * persistentStoreCoordinator; 12 13-(void) saveContext; 14-(NSURL *) applicationDocumentsDirectory; 15 16 17 @ end 18 19 20 21 // Appdelegate. the Code 22-(void) applicationWillTerminate :( UIApplication *) application {23 // Called when the application is about to terminate. save data if appropriate. see also applicationDidEnterBackground :. 24 // Saves chan Ges in the application's managed object context before the application terminates. 25 [self saveContext]; 26} 27 28 # pragma mark-Core Data stack 29 30 @ synthesize managedObjectContext = _ managedObjectContext; 31 @ synthesize managedObjectModel = _ managedObjectModel; 32 @ synthesize persistentStoreCoordinator = _ persistentStoreCoordinator; 33 34-(NSURL *) applicationDocumentsDirectory {35 // Directory the application uses to store the Core Data store file. this code uses a directory named "qq100858433.JMHitList" in the application's named ents directory. 36 return [[NSFileManager defaultManager] URLsForDirectory: NSDocumentDirectory inDomains: NSUserDomainMask] lastObject]; 37} 38 39-(optional *) managedObjectModel {40 // The managed object model for the application. it Is a fatal error for the application not to be able to find and load its model. 41 if (_ managedObjectModel! = Nil) {42 return _ managedObjectModel; 43} 44 NSURL * modelURL = [[NSBundle mainBundle] URLForResource: @ "JMHitList" withExtension: @ "momd"]; 45 _ managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL: modelURL]; 46 return _ managedObjectModel; 47} 48 49-(NSPersistentStoreCoordinator *) persistentStoreCoordinator {50 // The persistent store coordinator for the application. this im Plementation creates and returns a coordinator, having added the store for the application to it. 51 if (_ persistentStoreCoordinator! = Nil) {52 return _ persistentStoreCoordinator; 53} 54 55 // Create the coordinator and store 56 57 _ persistentStoreCoordinator = [[using alloc] Using: [self managedObjectModel]; 58 NSURL * storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent: @ "JMHitList. sqlite "]; 59 NSError * error = nil; 60 NSString * failureReason = @" There was Error creating or loading the application's saved data. "; 61 if (! [_ PersistentStoreCoordinator addPersistentStoreWithType: NSSQLiteStoreType configuration: nil URL: storeURL options: nil error: & error]) {62 // Report any error we got. 63 NSMutableDictionary * dict = [NSMutableDictionary dictionary]; 64 dict [NSLocalizedDescriptionKey] = @ "Failed to initialize the application's saved data"; 65 dict [partition] = failureReason; 66 dict [NSUnderlyingE RrorKey] = error; 67 error = [NSError errorWithDomain: @ "YOUR_ERROR_DOMAIN" code: 9999 userInfo: dict]; 68 // Replace this with code to handle the error appropriately. 69 // abort () causes the application to generate a crash log and terminate. you shoshould not use this function in a shipping application, although it may be useful during development. 70 NSLog (@ "Unresolved error % @, % @", error, [error us ErInfo]); 71 abort (); 72} 73 74 return _ persistentStoreCoordinator; 75} 76 77 78-(NSManagedObjectContext *) managedObjectContext {79 // Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application .) 80 if (_ managedObjectContext! = Nil) {81 return _ managedObjectContext; 82} 83 84 NSPersistentStoreCoordinator * coordinator = [self persistentStoreCoordinator]; 85 if (! Coordinator) {86 return nil; 87} 88 _ managedObjectContext = [[NSManagedObjectContext alloc] handler: Handler]; 89 [_ managedObjectContext handler: coordinator]; 90 return _ managedObjectContext; 91} 92 93 # pragma mark-Core Data Saving support 94 95-(void) saveContext {96 NSManagedObjectContext * managedObjectContext = self. managedObjectCont Ext; 97 if (managedObjectContext! = Nil) {98 NSError * error = nil; 99 if ([managedObjectContext hasChanges] &! [ManagedObjectContext save: & error]) {100 // Replace this implementation with code to handle the error appropriately.101 // abort () causes the application to generate a crash log and terminate. you shoshould not use this function in a shipping application, although it may be useful during development.102 NSLog (@ "Unresolved error % @, % @", error, [error userInfo]); 103 abort (); 104} 105} 106} 107 108 @ end

Assume that you are.xcdatamodeldThe following entity and entity attributes are generated:

 

The code for obtaining the database content and adding the database content in VC is as follows:

1 // obtain the existing Data from the Core Data. 2 id appDelegate = [UIApplication sharedApplication]. delegate; 3 NSManagedObjectContext * managedContext = [appDelegate managedObjectContext]; 4 NSFetchRequest * fetchRequest = [NSFetchRequest response: @ "Person"]; 5 @ try {6 self. people = [NSMutableArray arrayWithArray: [managedContext executeFetchRequest: fetchRequest error: nil]; 7} 8 @ catch (NSException * exce Ption) {9 NSLog (@ "cocould not fetch % @", [exception userInfo]); 10} 11 @ finally {12 NSLog (@ "Fetch Successful "); 13} 14 15 // Add the entity instance for the database 16 id appDelegate = [UIApplication sharedApplication]. delegate; 17 // NSManagedObjectContext can be viewed as the memory for processing managedObjects. 18 NSManagedObjectContext * mangedContext = [appDelegate managedObjectContext]; 19 // both of the following methods can obtain the Person object 20 // NSEntityDescription * entity = [NSEntityDes Cription entityForName: @ "Person" identifier: mangedContext]; 21 // NSManagedObject * person = [[NSManagedObject alloc] initWithEntity: entity identifier: mangedContext]; 22/[person setValue: name forKey: @ "name"]; 23 NSManagedObject * person = [NSEntityDescription insertNewObjectForEntityForName: @ "Person" inManagedObjectContext: mangedContext]; 24 [person setValue: name forKe Y: @ "name"]; 25 @ try {26 [mangedContext save: nil]; 27 [self. people addObject: person]; 28} 29 @ catch (NSException * exception) {30 NSLog (@ "cocould not save % @", [exception userInfo]); 31} 32 @ finally {33 NSLog (@ "Save Successfullt! "); 34}