Ios can'；t将UIBarButtonim添加到UIAbbarController内部的导航控制器

为什么不将

UIBarButtonItem

添加到我的导航控制器？

首先删除/注释下面的代码行

ViewController *VC = [[ViewController alloc] initWithNibName:nil bundle:nil];
UINavigationController *NavCon = [[UINavigationController alloc] initWithRootViewController:VC];
NavCon.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Close" style:UIBarButtonItemStyleBordered target:self action:@selector(showall)];
[self.myTabBarController setViewControllers:@[NavCon]];

然后将此代码放入导航控制器的viewController的

viewDidLoad

方法中

NavCon.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Close" style:UIBarButtonItemStyleBordered target:self action:@selector(showall)];

你能试试下面的代码吗

self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Close" style:UIBarButtonItemStyleBordered target:self action:@selector(showall)];

---

你可以这样做

VC.navigationController.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Close" style:UIBarButtonItemStyleBordered target:self action:@selector(showall)];
[self.myTabBarController setViewControllers:@[NavCon]];

---

不，它不工作，但如果我这样做，它工作了

VC.navigationItem.leftBarButtonItem=[[UIBarButtonItem alloc]initWithTitle:@“+”样式：UIBarbuttonItemStyleBordeded目标：自我操作：@selector（showall）]
UITabBarController *my = [[UITabBarController alloc]init];
    UIViewController *new =  [[UIViewController alloc]init];
    UINavigationController *nav = [[UINavigationController alloc]initWithRootViewController:new];
    new.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]initWithTitle:@"+" style:UIBarButtonItemStyleBordered target:new action:@selector(addButtonClicked:)];
    [my setViewControllers:@[nav]];