无法将UIBarButtonItem添加到UITabBarController内的navigationController

Question

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]];

为什么它不添加UIBarButtonItem到我的导航控制器？

Answer 1

首先删除/注释以下代码行

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

然后将此代码放在viewDidLoadnavContrller的viewController方法中.

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