暑期项目开发实训 Day18

用Sketch看设计图还是很方便的，不过有些部件看不太懂，

头脑有点凌乱，就记录一下解决的问题吧：

一、状态栏和导航栏的合并：

// 将navigation bar向上扩展，覆盖状态栏extension ItemViewController: UINavigationBarDelegate {    func position(for bar: UIBarPositioning) -> UIBarPosition {        return .topAttached    }}

二、删去Storyboard 和 LaunchScreen， 纯xib开发，运行时如何指定主界面(rootViewController)

修改AppDelegate的application(didFinishLaunchingWithOptions)

将Main.xib 和 Main.swift绑定

设置rootViewController

import UIKit@UIApplicationMainclass AppDelegate: UIResponder, UIApplicationDelegate {    var window: UIWindow?    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {                        // 将Main.xib和Main.swift绑定        let viewController = Main(nibName: "Main", bundle: nil)        let navigationController = UINavigationController(rootViewController: viewController)                self.window = UIWindow(frame: UIScreen.main.bounds)        self.window?.rootViewController = navigationController        self.window?.makeKeyAndVisible()        // Override point for customization after application launch.        return true    }   ......}

三、删去LaunchScreen后，运行时界面上下会出现黑条？

原因是缺少启动图

在Assets中加入相应尺寸的启动图即可。