UINavigationController 显示错误的视图

Question

我正在尝试实现一个基本的 UINavigationController ，但遇到了导航控制器显示错误视图的问题。

我首先在 Xcode 4 中创建一个基于窗口的应用程序，它为我提供了以下文件：spellingAppDelegate.h、spellingAppDelegate.m< /code> 和 MainWindows.xib。然后，我添加了一个新的 UIViewController 子类并将其命名为 gameViewController。

以下是我的 myAppDelegate.h 代码

#import <UIKit/UIKit.h>

@interface spellingAppDelegate : NSObject <UIApplicationDelegate> {
    UIWindow *window;
    UINavigationController *navigationController;
}


@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) UINavigationController *navigationController;

@end

以下是我的 myAppDelegate.m

#import "spellingAppDelegate.h"
#import "gameViewController.h"
#import "resultViewController.h"

@implementation spellingAppDelegate

@synthesize window = window;
@synthesize navigationController = navigationController;


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

    // create the MyView controller instance:
    gameViewController *controller = [[gameViewController alloc] initWithNibName:@"gameViewController" bundle:nil];

    // set the title that appears in the navigation bar:
    [controller.navigationItem setTitle:@"Main View"];

    // create the Navigation Controller instance:
    UINavigationController *newnav = [[UINavigationController alloc] initWithRootViewController:controller];

    // set the navController property:
    [self setNavigationController:newnav];

    // release both controllers:
    [newnav release];
    [controller release];

    // add the Navigation Controller's view to the window:
    [window addSubview:[navigationController view]];

    return YES;
}

我的印象是，如果我运行上述代码，应用程序将以 gameViewController.xib 启动。但是，它显示 MainWindow.xib。我知道我可能错过了一些基本的东西，但我不知道我做错了什么。谢谢。

Answer 1

试试这个，它会起作用

    navigationController = [[UINavigationController alloc] initWithRootViewController:controller];
   [self.window addSubview:navigationController.view];
   [self.window makeKeyAndVisible];

Answer 2

如果你这样做的话它会起作用

demoViewController *controller = [[demoViewController alloc] initWithNibName:@"demoViewController" bundle:nil];

// set the title that appears in the navigation bar:
[controller.navigationItem setTitle:@"Main View"];

// create the Navigation Controller instance:
UINavigationController *newnav = [[UINavigationController alloc] initWithRootViewController:controller];

// set the navController property:
//   [self setNavigationController:newnav];

[self.window addSubview:newnav.view];

// release both controllers:
[newnav release];
[controller release];

Answer 3

应用程序的窗口是在 nib 文件中定义的。通常，此笔尖是 MainWindow.xib，但您可以通过编辑应用程序的 info.plist 文件来更改它。

您可以在此 nib 中放置对要在启动时加载的视图控制器的引用（请参阅基于视图的应用程序模板），或者您可以在应用程序委托中使用 application:didFinishLaunchingWithOptions: 方法一样的效果。

在 iOS 4.0 及更高版本上，我将使用 UIWindow 属性 rootViewController 来添加视图控制器。例如：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{ 
    // Override point for customization after application launch.

    AViewController * aViewController = [[AViewController alloc] initWithNibName:nil bundle:nil];
    self.window.rootViewController = aViewController;
    [aViewController release];

    [self.window makeKeyAndVisible];
    return YES;
}