#pragma mark - Core Data stack
/**
* @synthesize 关联成员变量和属性
*/
@synthesize managedObjectContext = _managedObjectContext;
/**
*
*/
@synthesize managedObjectModel = _managedObjectModel;
@synthesize persistentStoreCoordinator = _persistentStoreCoordinator;
- (NSURL *)applicationDocumentsDirectory {
// The directory the application uses to store the Core Data store file. This code uses a directory named "CD._8_25_CoreData" in the application's documents directory.
return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}
- (NSManagedObjectModel *)managedObjectModel {
// 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.
if (_managedObjectModel != nil) {
return _managedObjectModel;
}
//找到momd文件在bundle中的途径。
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"_8_25_CoreData" withExtension:@"momd"];
_managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
return _managedObjectModel;
}
//重写get
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
// The persistent store coordinator for the application. This implementation creates and return a coordinator, having added the store for the application to it.
if (_persistentStoreCoordinator != nil) {
return _persistentStoreCoordinator;
}
// Create the coordinator and store
//创建数据存储器的文件路径
_persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"_8_25_CoreData.sqlite"];
NSError *error = nil;
NSString *failureReason = @"There was an error creating or loading the application's saved data.";
//coreData 不是对sqlite的封装，sqlite 只是其中一种存储方式
//coredata的核心思想是：托管对象
if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {
// Report any error we got.
NSMutableDictionary *dict = [NSMutableDictionary dictionary];
dict[NSLocalizedDescriptionKey] = @"Failed to initialize the application's saved data";
dict[NSLocalizedFailureReasonErrorKey] = failureReason;
dict[NSUnderlyingErrorKey] = error;
error = [NSError errorWithDomain:@"YOUR_ERROR_DOMAIN" code:9999 userInfo:dict];
// Replace this 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]);
//终止程序
abort();
}
return _persistentStoreCoordinator;
}
- (NSManagedObjectContext *)managedObjectContext {
// Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.)
if (_managedObjectContext != nil) {
return _managedObjectContext;
}
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (!coordinator) {
return nil;
}
//设置上下文
_managedObjectContext = [[NSManagedObjectContext alloc] init];
[_managedObjectContext setPersistentStoreCoordinator:coordinator];
return _managedObjectContext;
}
#pragma mark - Core Data Saving support
- (void)saveContext {
NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
if (managedObjectContext != nil) {
NSError *error = nil;
//如果上下文有修改，并且保存失败
if ([managedObjectContext hasChanges] && ![managedObjectContext 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();
}
}
}
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
// [self.tableView registerClass:[ UITableViewCell class] forCellReuseIdentifier:@"cell"];
self.dataArray = [NSMutableArray arrayWithCapacity:0];
AppDelegate *delegate = [UIApplication sharedApplication].delegate;
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Person"];
//在上下文内通过条件获取响应数据
NSArray *array = [delegate.managedObjectContext executeFetchRequest:request error:nil];
[self.dataArray addObjectsFromArray:array];
[self.tableView reloadData];
}
- (IBAction)addPerson:(UIButton *)sender {
AppDelegate *delegate = [UIApplication sharedApplication].delegate;
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Person" inManagedObjectContext:delegate.managedObjectContext];
Person *per = [[Person alloc] initWithEntity:entity insertIntoManagedObjectContext:delegate.managedObjectContext];
per.age = @(arc4random()%20 + 10);
NSArray *array = @[@"萌萌",@"波波",@"jack",@"rose",@"静静",@"000"];
per.name = array[arc4random() % (array.count)];
[self.dataArray addObject:per];
[self.tableView insertRowsAtIndexPaths:@[[NSIndexPath indexPathForRow:self.dataArray.count - 1 inSection:0]] withRowAnimation:UITableViewRowAnimationMiddle];
[self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:self.dataArray.count - 1 inSection:0] atScrollPosition:UITableViewScrollPositionBottom animated:YES];
}
- (IBAction)searchPerson:(UIButton *)sender {
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Person"];
request.predicate = [NSPredicate predicateWithFormat:@"age>18"];
AppDelegate *delegate = [UIApplication sharedApplication].delegate;
NSArray *array = [delegate.managedObjectContext executeFetchRequest:request error:nil];
[self.dataArray removeAllObjects];
[self.dataArray addObjectsFromArray:array];
}
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
AppDelegate *delegate = [UIApplication sharedApplication].delegate;
[delegate.managedObjectContext deleteObject:self.dataArray[indexPath.row]];
[self.dataArray removeObjectAtIndex:indexPath.row];
[tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationMiddle];
}
}