@UIApplicationMain class AppDelegate: UIResponder,UIApplicationDelegate {

    var window: UIWindow?

    func application(application: UIApplication!,didFinishLaunchingWithOptions launchOptions: NSDictionary!) -> Bool {

        self.window = UIWindow(frame: UIScreen.mainScreen().bounds)

        // ...

        self.window!.tintColor = UIColor.orangeColor()

        return true
    }
}

这是Swift等同于Objective-C：

@interface AppDelegate <UIResponder,UIApplicationDelegate>

@property (nonatomic,strong) UIWindow *window;

@end

@implementation AppDelegate

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

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

    // ...

    self.window.tintColor = [UIColor orangeColor];

    return YES;
}

@end

如果您正在使用故事板,请不要在AppDelegate中放置任何代码,只需更改故事板的“Global Tint”属性：