Question

我在UIViewController中添加了一个导航栏。它仅从另一个UIViewController显示。我想要一个左侧后退按钮，其形状类似于箭头，就像普通的导航栏后退按钮一样。我似乎只能通过IB添加一个条形按钮。我猜测后退按钮需要以编程方式添加。关于我应该怎么做的任何建议？

目前，在RootController中，我通过简单地执行addSubView来推送另一个UIViewController（viewB）。在viewB中，我想显示导航栏。该应用程序是基于视图的，而不是基于导航控制器。

Answer 1

如果您使用的是导航控制器：

MyViewController *_myViewController = [[MyViewController alloc] initWithNibName:@"MyViewController" bundle:nil];
[[self navigationController] pushViewController:_myViewController animated:YES];
UIBarButtonItem *_backButton = [[UIBarButtonItem alloc] initWithTitle:@"Back" style:UIBarButtonItemStyleDone target:nil action:nil];
self.navigationItem.backBarButtonItem = _backButton;
[_backButton release], _backButton = nil;
[_myViewController release], _myViewController = nil;

如果您没有使用导航控制器，请查看Three20 style组件以制作自定义栏按钮。

Answer 2

我已经按照以下方式完成了

在viewDidLoad方法中我有这段代码：

UINavigationBar *navBar = [[UINavigationBar alloc] initWithFrame:CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width, 41)];
    navBar.delegate = self;

    UINavigationItem *backItem = [[UINavigationItem alloc] initWithTitle:@"Back"];
    [navBar pushNavigationItem:backItem animated:NO];
    [backItem release];

    UINavigationItem *topItem = [[UINavigationItem alloc] initWithTitle:@"Your Title"];
    [navBar pushNavigationItem:topItem animated:NO];
    topItem.leftBarButtonItem = nil;
    [topItem release];

    [self.view addSubview:navBar];
    [navBar release];

然后在标头中添加符合UINavigationBarDelegate协议并以这种方式实现委托方法：

- (BOOL)navigationBar:(UINavigationBar *)navigationBar shouldPopItem:(UINavigationItem *)item
{
    //if you want to dismiss the controller presented, you can do that here or the method btnBackClicked

    return NO;
}

Answer 3

解决此问题的另一种方法是设置导航栏的items属性，而不是将条形项连续推入导航栏堆栈：

//Define myFrame based on your needs
let navigationBar = UINavigationBar(frame: myFrame)
let backItem = UINavigationItem(title: "Back")
let topItem = UINavigationItem(title: "My Title")
navigationBar.setItems([backItem,topItem], animated: false)

添加返回按钮到导航栏

3 个答案: