ios - iOS 应用程序是否需要 View Controller ？

Question

我一直在研究 iOS 应用程序结构，并且几乎了解了 MVC 范例，包括委托(delegate)、 View 和 Controller 。然后我在网上看到了一个例子，它只包含一个 AppDelegate 文件，没有 View 、 View Controller 或 nib 文件，它可以工作:

    @implementation AppDelegate

    - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

        self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
        self.window.backgroundColor = [UIColor whiteColor];

        CGRect bounds = self.window.bounds;
        view = [[UIView alloc] initWithFrame: bounds];
        [view setBackgroundColor: [UIColor yellowColor]];
        [self.window addSubview: view];

        CGRect labelFrame = CGRectMake(30, 30, 100, 30);
        label = [[UILabel alloc] initWithFrame: labelFrame];
        [label setText: @"My Label"];
        [label setTextAlignment: NSTextAlignmentCenter];
        [label setTextColor: [UIColor orangeColor]];
        [view addSubview: label];

        CGRect buttonFrame = CGRectMake(vCentre - 50, hCentre - 20, 100, 30);
        button = [[UIButton alloc] initWithFrame: buttonFrame];
        [button setTitle: @"My Button" forState: UIControlStateNormal];
        [[button titleLabel] setTextAlignment: NSTextAlignmentCenter];
        [button setTitleColor: [UIColor redColor] forState: UIControlStateNormal];
        [view addSubview: button];

        [button addTarget:self action:@selector(buttonClicked:) forControlEvents: UIControlEventTouchDown];

        [self.window makeKeyAndVisible];

        return YES;
    }

在没有设置任何 View Controller 或 Root View Controller 的情况下如何工作？这是否意味着实际上不需要 View Controller ？

Answer 1

您可以在 Interface Builder 中设计应用程序并连接所有 socket 。或者您可以在代码中设计窗口、标签等。

这将创建一个充满屏幕的窗口:

self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

然后向其中添加一个 View :

[self.window addSubview: view];

还有一个标签:

[view addSubview: label];

最后，显示窗口:

[self.window makeKeyAndVisible];