ios – 由于未捕获的异常’NSInvalidArgumentException’而终止应用程序,原因：’entityForName：nil不是合法的NSManagedObjectContext

我得到一个null结果

AppDelegate.h

@property (readonly,strong,nonatomic) NSManagedobjectContext *managedobjectContext;
@property (readonly,nonatomic) NSManagedobjectModel *managedobjectModel;
@property (readonly,nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator;

AppDelegate.m

@synthesize managedobjectContext = __managedobjectContext;
    @synthesize managedobjectModel = __managedobjectModel;
    @synthesize persistentStoreCoordinator = __persistentStoreCoordinator;

    - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
    {
          Person *newPerson = [NSEntityDescription
          insertNewObjectForEntityForName:@"Person"
          inManagedobjectContext:self.managedobjectContext];
          .......

    }

我有一个xcdatamodeld文件,其实体为Person,属性为name.我从NSManagedobject创建了一个Person.h和.m文件.

为什么我的输出结果为null.

Terminating app due to uncaught exception 'NSinvalidargumentexception',reason: '+entityForName: nil is not a legal NSManagedobjectContext parameter searching for entity name 'Person''

解决方法

在你的viewController.m实现文件中,就在这段代码下面：

- (void)viewDidLoad
{

添加这段代码：

id delegate = [[UIApplication sharedApplication] delegate];
    self.managedobjectContext = [delegate managedobjectContext];