Сбой проекта в строке self.window в Objective- C в Xcode 11

Question

Я использовал файл .xib и соответствующие ему файлы .h и .m, чтобы показать простой сканер штрих-кода в моем приложении. Код Appdelegate имеет вид:

    #import "AppDelegate.h"
#import "BarcodeScannerVC.h"

@interface AppDelegate ()

@end

@implementation AppDelegate


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
    self.window = [[UIWindow alloc]initWithFrame:[[UIScreen mainScreen] bounds]];
    BarcodeScannerVC *homeVc = [[BarcodeScannerVC alloc]initWithNibName:@"BarcodeScannerVC" bundle:nil];
    UINavigationController *nav = [[UINavigationController alloc]initWithRootViewController:homeVc];
    self.window.rootViewController = nav;
    [self.window makeKeyAndVisible];
    return YES;
}


#pragma mark - UISceneSession lifecycle


- (UISceneConfiguration *)application:(UIApplication *)application configurationForConnectingSceneSession:(UISceneSession *)connectingSceneSession options:(UISceneConnectionOptions *)options {
    // Called when a new scene session is being created.
    // Use this method to select a configuration to create the new scene with.
    return [[UISceneConfiguration alloc] initWithName:@"Default Configuration" sessionRole:connectingSceneSession.role];
}


- (void)application:(UIApplication *)application didDiscardSceneSessions:(NSSet<UISceneSession *> *)sceneSessions {
    // Called when the user discards a scene session.
    // If any sessions were discarded while the application was not running, this will be called shortly after application:didFinishLaunchingWithOptions.
    // Use this method to release any resources that were specific to the discarded scenes, as they will not return.
}


@end

Но, по незнанию, происходит сбой приложения в строке «self.window», которую можно увидеть на изображении ниже:

Это структура файла:

В чем проблема?

Answer 1

Я думаю, вы должны использовать класс SceneDelegate

@implementation SceneDelegate

- (void)scene:(UIScene *)scene willConnectToSession:(UISceneSession *)session options:(UISceneConnectionOptions *)connectionOptions {

self.window = [[UIWindow alloc] initWithWindowScene:(UIWindowScene *)scene];
UIViewController *vc = [[UIViewController alloc] init];
UINavigationController *nav = [[UINavigationController alloc]initWithRootViewController:vc];
self.window.rootViewController = nav;
[self.window makeKeyAndVisible];
}

Answer 2

попробуйте создать новую ссылку из UIWindow.

`- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
CGRect windowFrame = UIScreen.mainScreen.bounds;
UIWindow *theWindow = [[UIWindow alloc] initWithFrame:windowFrame];
UIViewController *viewController = [[UIViewController alloc] initWithNibName:nil bundle:nil];
theWindow.rootViewController = viewController;
[self setWindow:theWindow];
return YES;

}