Xcode11-建立項目UISceneDelegate

UISceneDelegate

• 在Xcode11中新建項目，發現從iOS13開始，AppDelegate中再也不管理Window，而是將功能遷移到了SceneDelegate中。

• 首先看一下info.plist 的變化

• enable Multipe Windows --- 是否容許分屏
• Scene Configuratiton --- 屏幕配置項
• Application Session Role --- 程序屏幕配置規則（爲每一個Scene指定規則）
• Configuration Name --- 配置名稱
• Delegate Class Name --- 代理類名稱
• Storyboard Name --- Storyboard名稱

• 根據上面配置，咱們能夠解讀爲，建立項目時，系統默認爲咱們作了設置，一個名爲Default Configuratiton 的默認配置，代理類名稱爲SceneDelegate,入口名爲Main的Storyboard，
• AppDelegate中代碼以下

#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];
}

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那麼問題來了，想要自定義Window,不經過Storyboard建立，該如何操做?

在iOS13及以上系統

• 若是繼續使用SceneDelegate，須要將info.plist中的Storyboard Name選項刪除（即不指定Storyboard）
• SceneDelegate中代碼修改以下：

- (void)scene:(UIScene *)scene willConnectToSession:(UISceneSession *)session options:(UISceneConnectionOptions *)connectionOptions {
    if (@available(ios 13, *)) {
         if (scene) {
             self.window = [[UIWindow alloc] initWithWindowScene:(UIWindowScene *)scene];
             self.window.frame = CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height);
             UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:[[ViewController alloc]init]];
             self.window.rootViewController = nav;
             [self.window makeKeyAndVisible];
         }
     }
}

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低於iOS13的系統

• 刪除info.plist文件中的Application Scene Manifest選項
• 刪除SceneDelegate文件
• 刪除AppDelegate中的SceneDelegate方法
• AppDelegate.h中添加

@property (strong, nonatomic) UIWindow *window;
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• AppDelegate修改代碼以下：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
    ViewController * vc = [[ViewController alloc]init];
    UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:vc];
    self.window.rootViewController = nav;
    [self.window makeKeyAndVisible];
    return YES;
}
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