Xcode 建立iOS13以下項目（OC、Swift）

1.建立項目

2.解決ios13以下運作閃退問題

1）删除SceneDelegate.swift

官方文檔：
In iOS 13 and later, use UISceneDelegate objects to respond to life-cycle events in a scene- 
based app.

這個場景呢，如果不使用ipad的多視窗就不建議使用
           

2）删除 Main.storyboard，不使用storyboard布局，打開info.plist，删除Main storyboard file base name和Application Scene Manifest選項。

3）删除appdelegate 中關于scene的2個代理

4）appdelegate中添加根導航

//swift
class AppDelegate: UIResponder, UIApplicationDelegate {
    var window: UIWindow?
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        let screen = UIScreen.main.bounds        //獲得裝置尺寸
        self.window = UIWindow.init(frame: screen) //給“輸出視窗“執行個體化并設定frame
        let viewController = ViewController() //執行個體化一個ViewController
        let navigationController = UINavigationController(rootViewController: viewController)  //為ViewController設定一個導航欄
        self.window?.rootViewController = navigationController//将“輸出視窗”的根視圖設定為導航欄
        self.window?.makeKeyAndVisible()       //  設定"輸出視窗可見"
        return true
    }
}




//OC 
@interface AppDelegate ()<UISplitViewControllerDelegate>
    @property (strong, nonatomic) UIWindow *window;
@end
@implementation AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window = [[UIWindow alloc]init];
    self.window.frame = [UIScreen mainScreen].bounds;
    LogInViewController *loginVC = [[LogInViewController alloc]initWithNibName:@"LogInViewController" bundle:nil];
    self.window.rootViewController = loginVC;
    [self.window makeKeyAndVisible];
    return YES;
}
           

參考自：https://www.xugj520.cn/archives/xcode-swift.html