无法导航到另一个 ViewController

Question

我是新手。 ViewController.m 中有一个按钮。当我按下按钮时，它必须导航到 SecondViewController 但 SecondViewController 没有出现。

并且在导航栏的SecondViewController处，会有“Back”按钮回到ViewController。你能告诉我我错过了什么吗？

ViewController.m：

-(IBAction)buttonPressed:(id)sender
{

    EnglishViewController *v = [[[EnglishViewController alloc]
                                initWithNibName:@"EnglishViewController"
                                bundle:nil]
                               autorelease];


    [self.navigationController pushViewController:v animated:TRUE];
}

AppDelegate.m：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
    // Override point for customization after application launch.
    self.viewController = [[[ViewController alloc] initWithNibName:@"ViewController" bundle:nil] autorelease];
    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];
    return YES;
}

解决方案（取决于@George 的回答）：

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

    self.viewController = [[[ViewController alloc] initWithNibName:@"ViewController" bundle:nil] autorelease];
    UINavigationController *navCon =[[[UINavigationController alloc]
                                      initWithRootViewController:self.viewController]
                                     autorelease];

    self.window.rootViewController =navCon;

    [self.window makeKeyAndVisible];
    return YES;
}

Answer 1

当您在 AppDelegate.m 中创建您的 ViewController 时，您必须用 navigationController 包围它才能使其工作

类似这样的：

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

    self.viewController = [[[ViewController alloc] initWithNibName:@"ViewController" bundle:nil] autorelease];
    UINavigationController *navigation = [[UINavigationController alloc] initWithRootViewController:self.viewController];
    self.window.rootViewController = navigation;
    [navigation release];

    [self.window makeKeyAndVisible];
    return YES;
}

Answer 2

首先要检查的几件事：你的-buttonPressed 方法是否真的被调用了？您是否正在获取非零值并将其传递给-pushViewController:animated:？当您拨打电话时，self.navigationController 实际上不是零吗？

您的代码看起来不错。