问题描述

如何根据设备类型启动特定的视图

在启动时候有三个视图，想要实现的是可以根据设备类型来选择三个中的一个。目前我写的代码在AppDelegate.m中

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];    // 应用启动后重写制定    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone && [UIScreen mainScreen].bounds.size.height == 568.0) {        self.viewController = [[ViewController alloc] initWithNibName:@""ViewController_Portrait5"" bundle:nil];    }    else if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone && [UIScreen mainScreen].bounds.size.height == 480.0) {        self.viewController = [[ViewController alloc] initWithNibName:@""ViewController_Portrait4"" bundle:nil];    }    else {        self.viewController = [[ViewController alloc] initWithNibName:@""ViewController_PortraitPad"" bundle:nil];    }}

但是运行之后，应用启动的时候屏幕一片漆黑。
怎么解决，谢谢。

解决方案

在方法的最后添加：

self.window.rootViewController = self.viewController;[self.window makeKeyAndVisible];

解决方案二：
用以下代码，更简洁一些。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];    NSString *nibName;    if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {        nibName = @""ViewController_PortraitPad"";    } else {        if ([UIScreen mainScreen].bounds.size.height == 480.0) {            nibName = @""ViewController_Portrait4"";        } else {            nibName = @""ViewController_Portrait5"";        }    }    self.viewController = [[ViewController alloc] initWithNibName:nibName bundle:nil];    self.window.rootViewController = self.viewController;    [self.window makeKeyAndVisible];