ios6 - 在没有 Storyboard 的 iOS 6 上保存和恢复应用程序状态

Question

我已经按照这个 tutorial 完成了测试应用程序

我尝试在不使用 Storyboard 的情况下做同样的事情，但它不起作用。我在 AppDelegate 中启用了状态保存和恢复。我已将 restoreIdentifier 分配给我的所有 Controller 及其 View 。我想我必须在 AppDelegate 中实现一些额外的代码来恢复 rootviewcontroller，但我找不到正确的方法。

-(BOOL)application:(UIApplication *)application shouldRestoreApplicationState:(NSCoder *)coder
{
    return YES;
}

-(BOOL)application:(UIApplication *)application shouldSaveApplicationState:(NSCoder *)coder
{
    return YES;
}


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

    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
    // Override point for customization after application launch.
    UIViewController *viewController1 = [[[StateTestFirstViewController alloc] initWithNibName:@"StateTestFirstViewController" bundle:nil] autorelease];
    UIViewController *viewController2 = [[[StateTestSecondViewController alloc] initWithNibName:@"StateTestSecondViewController" bundle:nil] autorelease];
    self.tabBarController = [[[UITabBarController alloc] init] autorelease];
    self.tabBarController.restorationIdentifier = @"TabBarController";
    self.tabBarController.viewControllers = @[viewController1, viewController2];
    self.window.rootViewController = self.tabBarController;

    [self.window makeKeyAndVisible];

    return YES;
}

Answer 1

实际上，您的 View Controller 在 application:willFinishLaunchingWithOptions: 和 application:didFinishLaunchingWithOptions: 之间恢复，所以如果您将代码更改为:

- (BOOL)application:(UIApplication *)application willFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];

    UIViewController *viewController1 = [[[StateTestFirstViewController alloc] initWithNibName:@"StateTestFirstViewController" bundle:nil] autorelease];
    UIViewController *viewController2 = [[[StateTestSecondViewController alloc] initWithNibName:@"StateTestSecondViewController" bundle:nil] autorelease];
    self.tabBarController = [[[UITabBarController alloc] init] autorelease];
    self.tabBarController.restorationIdentifier = @"TabBarController";
    self.tabBarController.viewControllers = @[viewController1, viewController2];
    self.window.rootViewController = self.tabBarController;
    return YES;
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {                
    [self.window makeKeyAndVisible];

    return YES;
}

它对我有用。另外我建议您观看WWDC 2012 Session 208 — Saving and Restoring Application State on iOS .