纯代码初始化项目首先在配置也做以下修改:删除Main Interface中的内容,则程序运行时会先去AppDelegate中执行相关的代码。
然后在Appdelegate.swift中添加如下代码:
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
//创建指定window
window = UIWindow.init(frame: UIScreen.main.bounds)
//指定window显示的控制器
window?.rootViewController = nil
//让window成为主windows且可访问
window?.makeKeyAndVisible()
return true
}
}