项目在Xcode 11中Objective-C中的self.window行崩溃

Question

我一直在使用.styleboard文件以及相应的.h和.m文件来在我的应用程序中显示一个简单的条形码扫描仪。

这背后的问题是什么？

Answer 1

尝试从UIWindow创建新引用。

`- (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;

}

Answer 2

我认为您应该使用SceneDelegate类

@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];
}