iPad：没有“弹出按钮”的 UISplitViewController？

Question

我有一个 UISplitViewController （完美工作），我想在顶部显示按钮以纵向模式显示弹出菜单。

AppDelegate 代码

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

    splitViewController = [[MySplitViewController alloc] init];

    MasterViewController *master = [[MasterViewController alloc] init];
    PicsTableViewController *detail = [[PicsTableViewController alloc] init]; 

    //create NavigationControllers
    UINavigationController *masterNav = [[UINavigationController alloc] initWithRootViewController:master];
    UINavigationController *detailNav = [[UINavigationController alloc] initWithRootViewController:detail];

    [master release];

    splitViewController.viewControllers = [NSArray arrayWithObjects:masterNav, detailNav, nil];
    [masterNav release]; [detailNav release];
    splitViewController.delegate = detail;
    [detail release];

    [self.window addSubview:splitViewController.view];
    [self.window makeKeyAndVisible];

    return YES;
}

PicsTableViewController（委托）代码：

//add button on top
- (void)splitViewController:(UISplitViewController *)svc
     willHideViewController:(UIViewController *)aViewController
          withBarButtonItem:(UIBarButtonItem*)barButtonItem
       forPopoverController:(UIPopoverController*)pc
{
    barButtonItem.title = aViewController.title;
    self.navigationItem.rightBarButtonItem = barButtonItem;
}

- (void)splitViewController:(UISplitViewController *)svc
     willShowViewController:(UIViewController *)aViewController
  invalidatingBarButtonItem:(UIBarButtonItem *)button
{
    self.navigationItem.rightBarButtonItem = nil;
}

按钮永远不会出现，我的代码有什么问题？ 谢谢

Answer 1

检查aViewController确实具有title属性，如果没有任何字母，则按钮不会出现。

我刚遇到同样的问题，当我硬编码时：

barButtonItem.title = [NSString stringWithFormat:@"hello"];

按钮出现并工作。

我认为引用导航没有标题，这就是它不起作用的原因。