iphone - 当我将新 View Controller 推送到 self.navigation Controller 时应用程序崩溃了

Question

我有一个 iOS 5 应用程序。
当我想将 View 推送到导航 Controller 时，应用程序崩溃:(

这是我的 appDelegate 部分:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.


    self.navigationController=[[UINavigationController alloc] init];

    StartViewController *startViewController=[[StartViewController alloc] init];
    [self.navigationController pushViewController:startViewController animated:YES];
    [self.navigationController setNavigationBarHidden:YES];
    [[UIApplication sharedApplication] setStatusBarHidden:YES];

    self.window.backgroundColor = [UIColor whiteColor];
    self.window.rootViewController=self.navigationController;
    [self.window makeKeyAndVisible];
    return YES;
}

这是我推新的 View Controller 方法:

-(IBAction)startPressed:(id)sender
{
    NSLog(@"startPressed: called");
    //loading RootViewController (mainscreen view)
    RootViewController *rootViewController=[[RootViewController alloc] init];
    [self.navigationController pushViewController:rootViewController animated:YES];
}

应用程序在字符串 [self.navigationController pushViewController:rootViewController animated:YES]; 处崩溃

请帮帮我。如何解决这个问题呢？

Answer 1

UINavigationController 需要一个 rootviewController:

StartViewController *startViewController=[[StartViewController alloc] init];
self.navigationController=[[UINavigationController alloc] initWithRootViewControllr:startViewController];

[self.navigationController setNavigationBarHidden:YES];
[[UIApplication sharedApplication] setStatusBarHidden:YES];

更改

@autoreleasepool { 
     return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class])); 
}

到

NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
int retVal = UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class])); 
[pool release];

return retVal;