ios - nil中的managedObjectModel(仅在WatchApp中)

Question

我正在更新Apple Watch的应用程序
这个应用程序使用coredata，所以我创建了一个框架来管理Core Data堆栈!
当我在设备或模拟器上运行该应用程序时，该应用程序运行良好，但是当我在Apple Watch模拟器上运行该应用程序时，此日志崩溃

***由于未捕获的异常“NSInvalidArgumentException”而终止应用程序，原因:“无法创建
带有nil模型的NSPersistentStoreCoordinator

问题似乎是managedObjectModel，如果我将其记录下来

NSLog(@"managedObjectModel %@", _managedObjectModel);

日志返回

managedObjectModel(空)

框架中的代码似乎正确，实际上主应用程序完美运行

无论如何，这就是框架的内容

#import "DataAccess.h"

@implementation DataAccess

@synthesize managedObjectContext = _managedObjectContext;
@synthesize managedObjectModel = _managedObjectModel;
@synthesize persistentStoreCoordinator = _persistentStoreCoordinator;


+ (instancetype)sharedInstance
{
    static DataAccess *sharedInstance = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sharedInstance = [[DataAccess alloc] init];
        // Do any other initialisation stuff here
    });
    return sharedInstance;
}

- (void)saveContext
{
    NSError *error = nil;
    NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
    if (managedObjectContext != nil) {
        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();
        }
    }
}



#pragma mark - Core Data stack

// Returns the managed object context for the application.
// If the context doesn't already exist, it is created and bound to the persistent store coordinator for the application.
- (NSManagedObjectContext *)managedObjectContext
{
    if (_managedObjectContext != nil) {
        return _managedObjectContext;
    }

    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
    if (coordinator != nil) {
        _managedObjectContext = [[NSManagedObjectContext alloc] init];
        [_managedObjectContext setPersistentStoreCoordinator:coordinator];
    }
    return _managedObjectContext;
}

// Returns the managed object model for the application.
// If the model doesn't already exist, it is created from the application's model.
- (NSManagedObjectModel *)managedObjectModel
{
    if (_managedObjectModel != nil) {

        NSLog(@"managedObjectModel %@", _managedObjectModel);

        return _managedObjectModel;

    }
    NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"MyApp" withExtension:@"momd"];
    _managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];

    NSLog(@"managedObjectModel %@", _managedObjectModel);


    return _managedObjectModel;
}

// Returns the persistent store coordinator for the application.
// If the coordinator doesn't already exist, it is created and the application's store added to it.
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
    if (_persistentStoreCoordinator != nil) {
        return _persistentStoreCoordinator;
    }

    //NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"TMM.sqlite"];
    //NSURL *storeURL = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory  inDomains:NSAllDomainsMask] lastObject];
//    storeURL = [storeURL URLByAppendingPathComponent:@"db.sqlite"];

    NSURL *storeURL = [[NSFileManager defaultManager] containerURLForSecurityApplicationGroupIdentifier:@"group.ragazzetto.MyApp.Documents"];
    storeURL = [storeURL URLByAppendingPathComponent:@"MyApp.sqlite"];

    NSError *error = nil;
    _persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];

    if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {

        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }

    return _persistentStoreCoordinator;
}
#pragma mark - Application's Documents directory

// Returns the URL to the application's Documents directory.
- (NSURL *)applicationDocumentsDirectory
{
    return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}


@end

问题出在哪里 ？

感谢您的帮助

Answer 1

当您编写iOS应用扩展程序(包括所有当前的WatchKit应用程序)时，您将使用其自己的捆绑包创建一个单独的可执行文件。应用程序中的资源不一定在扩展程序中可用，反之亦然。因此，当您执行此操作时:

NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"MyApp" withExtension:@"momd"];
_managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];

在WatchKit应用程序中运行时，URL与包含应用程序中的URL不同。该错误告诉您WatchKit应用程序的URL无效，即WatchKit应用程序包中没有模型文件。

简单的解决方法是仅将模型包含在WatchKit捆绑包中。为此，请执行以下操作:

在Xcode中选择模型文件

打开Xcode窗口右侧的文件检查器面板

在“目标成员资格”部分中查找。确保选择了WatchKit目标。

那应该可以，但是将意味着您有两个模型文件副本。更好的方法是将模型文件放入两个目标都使用的共享框架中。稍微复杂一点，但是稍作搜索就会找到详细的步骤。