第二步：为项目添拍则岁加 CoreData.framework 框架，然后在 .pch 中加入盯胡 #import <coredata/coredata.h>
第三步：在 app delegate 中定义 core data 的相关对象（同时完成它们的初始化工作）
.h 文件：
#import <coredata/coredata.h>
@private
NSManagedObjectModel *managedObjectModel
NSManagedObjectContext *managedObjectContext
NSPersistentStoreCoordinator *persistentStoreCoordinator
@property (nonatomic, retain, readonly) NSManagedObjectModel *managedObjectModel
@property (nonatomic, retain, readonly) NSManagedObjectContext *managedObjectContext
@property (nonatomic, retain, readonly) NSPersistentStoreCoordinator *persistentStoreCoordinator
- (NSString*) applicationDocumentsDirectory
- (void) saveContext
.m 文件：
@synthesize managedObjectModel
@synthesize managedObjectContext
@synthesize persistentStoreCoordinator
- (void)dealloc {
[managedObjectModel release]
[managedObjectContext release]
[persistentStoreCoordinator release]
[super dealloc]
}
- (NSString*)applicationDocumentsDirectory
{
//return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject]
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)
NSString *basePath = ([paths count] >0) ? [paths objectAtIndex:0] : nil
return basePath
//return [NSURL URLWithString:basePath]
}
- (void)saveContext{
NSError *error = nil
NSManagedObjectContext *objectContext = self.managedObjectContext
if (objectContext != nil)
{
if ([objectContext hasChanges] &&![objectContext save:&error])
{
NSLog(@"Unresolved error %@, %@", error, [error userInfo])
abort()
}
}
}
- (NSManagedObjectContext *)managedObjectContext
{
if (managedObjectContext != nil) {
return managedObjectContext
}
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator]
if (coordinator != nil) {
managedObjectContext = [[NSManagedObjectContext alloc] init]
[managedObjectContext setPersistentStoreCoordinator:coordinator]
}
return managedObjectContext
}
- (NSManagedObjectModel *)managedObjectModel
{
if (managedObjectModel != nil) {
return managedObjectModel
}
//从本地所有 xcdatamodel 文件中获得这个 CoreData 的数据模板
managedObjectModel = [[NSManagedObjectModel mergedModelFromBundles:nil] retain]
return managedObjectModel
}
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
if (persistentStoreCoordinator != nil) {
return persistentStoreCoordinator
}
//数据库名为TestDB.sqlite
NSURL *storeUrl = [NSURL fileURLWithPath:[[self applicationDocumentsDirectory] stringByAppendingPathComponent:@"TestDB.sqlite"]]
NSError *error
persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]]
if (![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nilURL:storeUrl options:nil error:&error]) {
NSAssert(0, @"persistentStoreCoordinator init failed!")
}
return persistentStoreCoordinator
}
- (void)applicationWillTerminate:(UIApplication *)application
{
NSError *error
if (managedObjectContext != nil) {
if ([managedObjectContext hasChanges] &&![managedObjectContext save:&error]) {
NSAssert(0, @"save changes failed when terminage application!")
}
}
}
第四步：在相关的 viewcontroller 中 *** 作数据，基本的 core data *** 作代码如下：
NSError *error
testSQLiteAppDelegate *app = (testSQLiteAppDelegate*)[[UIApplication sharedApplication] delegate]
NSManagedObjectContext *context = app.managedObjectContext
//1、插入
NSManagedObject *newManagedObject = nil
newManagedObject = [NSEntityDescription insertNewObjectForEntityForName:@"Entity1" inManagedObjectContext:context]
[newManagedObject setValue:[NSNumber numberWithInt:1] forKey:@"id"]
[newManagedObject setValue:@"i love you" forKey:@"name"]
if (![context save:&error]){
NSLog (@"The error is: %@", [error userInfo])
}
else
{
NSLog (@"The newManagedObject's id is: %@", [newManagedObject valueForKey:@"id"])
}
//2、查询
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Entity1" inManagedObjectContext:context]
NSSortDescriptor *sortDescriptor1 = [[NSSortDescriptor alloc] initWithKey:@"id" ascending:YES]
NSSortDescriptor *sortDescriptor2 = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES]
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor1, sortDescriptor2, nil]
[fetchRequest setSortDescriptors:sortDescriptors]
[fetchRequest setEntity:entity]
[fetchRequest setFetchBatchSize:20]
NSArray *objects = [context executeFetchRequest: fetchRequest error:&error]
if (objects == nil)
{
NSLog(@"There was an error!")
}
else {
for (NSManagedObject *oneObject in objects)
{
NSLog(@"%@",[oneObject valueForKey:@"name"])
}
}
//3、删除
[context deleteObject:[objects objectAtIndex:0]]
if (![context save:&error]) {
exit(-1)
}
这里更详细的补充一点关于 core data 的 *** 作代码：
1、条件过滤:选择 cid=1 的数据
- (NSFetchedResultsController*) fetchedResultsController
{
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"cid=1"]
[fetchRequest setPredicate:predicate]
}
2、通用代码，在 viewcontroller 里面会用到：
TestViewController.h 的代码：
@interface TestViewController : UITableViewController <NSFetchedResultsControllerDelegate>
{
NSFetchedResultsController *fetchedResultsController
NSManagedObjectContext *managedObjectContext
}
@property (nonatomic, retain) NSFetchedResultsController *fetchedResultsController
@property (nonatomic, retain) NSManagedObjectContext *managedObjectContext
- (void)configureCell:(UITableViewCell *)cell withCategory:(Category *)category
@end
TestViewController.m 的代码：
-(NSFetchedResultsController *)fetchedResultsController
{
if (fetchedResultsController != nil)
{
return fetchedResultsController
}
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Category" inManagedObjectContext:managedObjectContext]
[fetchRequest setEntity:entity]
NSSortDescriptor *nameDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES]
NSArray *arraySortDescriptor = [[NSArray alloc] initWithObjects:nameDescriptor, nil]
[fetchRequest setSortDescriptors:arraySortDescriptor]
NSPredicate *predicate = [NSPredicate predicateWithFormat:cidString]
[fetchRequest setPredicate:predicate]
NSFetchedResultsController *frController = [[NSFetchedResultsController alloc]
initWithFetchRequest:fetchRequest managedObjectContext:managedObjectContext sectionNameKeyPath:@"name" cacheName:@"Root"]
frController.delegate = self
self.fetchedResultsController = frController
[frController release]
[fetchRequest release]
[nameDescriptor release]
return fetchedResultsController
}
- (void)controllerWillChangeContent:(NSFetchedResultsController *)
{
[self.tableView beginUpdates]
}
- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject
atIndexPath:(NSIndexPath *)indexPath forChangeType: (NSFetchedResultsChangeType)type
newIndexPath:(NSIndexPath *)newIndexPath
{
UITableView *tableView = self.tableView
switch (type) {
case NSFetchedResultsChangeInsert:
[tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade]
break
case NSFetchedResultsChangeDelete:
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade]
break
case NSFetchedResultsChangeMove:
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade]
[tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade]
break
case NSFetchedResultsChangeUpdate:
[self configureCell:[tableView cellForRowAtIndexPath:indexPath] withCategory:anObject]
break
default:
break
}
}
- (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo
atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type
{
switch(type) {
case NSFetchedResultsChangeInsert:
[self.tableView insertSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade]
break
case NSFetchedResultsChangeDelete:
[self.tableView deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade]
break
}
}
- (void) controllerDidChangeContent:(NSFetchedResultsController *)controller
{
[self.tableView endUpdates]
}
2.创建数据模块型敏
3.创建对应的类
这升段时候创建不是右键创建，通过主菜吵租誉单 Editor ->Create NSManagedObject Subclass
4.自动会为数据模块创建两个类文件
6.添加数据
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