初始化UI导航栏

Question

我在制作顶部有导航栏或控制器的表视图时遇到问题。

我有一段代码，

- (void)viewDidLoad {
    [super viewDidLoad];
    UINavigationController *addNavCon = [[UINavigationController alloc]initWithNibName:@"Welcome" bundle:nil];
    self.navigationItem.rightBarButtonItem = self.addButtonItem;
    self.navigationItem.leftBarButtonItem = self.editButtonItem;


    [self createEditableCopyOfDatabaseIfNeeded];    
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationWillTerminate:) name:UIApplicationWillTerminateNotification object:nil];
    NSString *documentDirectory = [self applicationDocumentsDirectory];
    NSString *path = [documentDirectory stringByAppendingPathComponent:@"notebook.plist"];
    NSMutableArray *tmpArray = [[NSMutableArray alloc] initWithContentsOfFile:path];
    self.Notes = tmpArray;
    [tmpArray release];

}

但是，导航栏永远不会显示，而表运行良好。我可以知道代码出了什么问题吗？

非常感谢

Answer 1

您已经创建了UINavigationController的实例，但从未将其添加到任何内容中。您需要将它添加到当前层次结构中，否则它将不会出现。

如果你想将导航控制器添加到整个应用程序中，那么你应该在的应用程序代理中这样做

- (void)applicationDidFinishLaunching:(UIApplication *)application
{
    UIViewController *rootController = [[MyRootViewController alloc] init];
    UINavigationController *navigationController = [[UINavigationController alloc]
                                initWithRootViewController:rootController];
    [rootController release];

    window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    [window addSubview:navigationController.view];
    [window makeKeyAndVisible];
}