Xcode11新建项目移除SceneDelegate

1、删除SceneDelegate.h、SceneDelegate.m文件

2、删除info.plist文件相关项Application Scene Manifest

3、删除AppDelegate.m文件相关SceneDelegate代码

#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.
}

4、在AppDelegate.h中，补回window属性

#import <UIKit/UIKit.h>

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@end

5、纯代码需要完善AppDelegate.m的window实例化

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    [self.window setRootViewController:[[ViewController alloc]init]];
    [self.window makeKeyAndVisible];
    return YES;
}