在打开多任务栏之前看不可见 - iPhone

Question

我在iPhone 3.5英寸显示屏ios 5.1上运行时首次出现自动布局崩溃 - 通过关闭自动布局来修复此问题。但是，现在，当我运行应用程序时，屏幕是黑色的。仅当我双击主页按钮以唤起多任务栏时，才能看到该视图。很奇怪，对吗？

在应用启动时：

唤起多任务处理。

代码段：

   if(screenSize.height == 480) {
        // iPhone Classic
        welcomeViewController = [welcomeViewController initWithNibName:@"WelcomeViewController~iphone3.5" bundle:nil];
        viewController = [viewController initWithNibName:@"selectZone~iphone3.5" bundle:nil];
        fixtureViewController = [fixtureViewController initWithNibName:@"fixture~iphone3.5" bundle:nil];

        [windowOldiPhone addSubview:fixtureViewController.view]; 
        [windowOldiPhone addSubview:viewController.view];
        [windowOldiPhone addSubview:welcomeViewController.view];
        [windowOldiPhone makeKeyAndVisible];
        [windowOldiPhone bringSubviewToFront:welcomeViewController.view];
    }

注意：在运行iOS 6的iPhone / iPad上不会发生这种情况。

Answer 1

在致电bringSubviewToFront之前致电makeKeyAndVisible。如下所示

if(screenSize.height == 480) {
        // iPhone Classic
        welcomeViewController = [welcomeViewController initWithNibName:@"WelcomeViewController~iphone3.5" bundle:nil];
        viewController = [viewController initWithNibName:@"selectZone~iphone3.5" bundle:nil];
        fixtureViewController = [fixtureViewController initWithNibName:@"fixture~iphone3.5" bundle:nil];

        [windowOldiPhone addSubview:fixtureViewController.view]; 
        [windowOldiPhone addSubview:viewController.view];
        [windowOldiPhone addSubview:welcomeViewController.view];

        [windowOldiPhone bringSubviewToFront:welcomeViewController.view];
 [windowOldiPhone makeKeyAndVisible];
    }