在UINavigationController中为所有视图控制器添加相同的按钮 [英] Adding same button to all view controllers in UINavigationController

问题描述

我有一个 UINavigationController （用作向导页面）我以编程方式创建，我需要显示取消按钮以取消任何<$中的进程c $ c> UIViewController 。

I have a UINavigationController (to use like a wizard page) which I create programmatically and I need to display a "Cancel" button to cancel the process in any UIViewController.

创建 UINavigationController ：

FirstVC *firstVC = [[[FirstVC alloc] initWithNibName:@"FirstPage" bundle:nil] autorelease];
firstVC.delegate = self;

navigationController = [[UINavigationController alloc] initWithRootViewController:firstVC];
[self.view addSubview:navigationController.view];

添加取消按钮：

UIBarButtonItem *cancelButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(cancelRequestNewLeave:)];
navigationController.topViewController.navigationItem.rightBarButtonItem = cancelButton;
[cancelButton release];

但当我将第二页推到 UINavigationController 取消按钮未显示在 UINavigationBar 上。如果我回到第一页，取消按钮就在那里。所以，显然只为第一个视图添加了按钮。我相信这是因为我没有继承 UINavigationController ，因为我需要在子视图中使用它。但我不知道如何在以编程方式创建的 UINavigationController 中设置 rightBarButtonItem 。

But when I push a second page to UINavigationController the cancel button is not shown on the UINavigationBar. If I go back to first page, the cancel button is there. So, apparently the button is added only for the first view. I believe this is because I'm not subclassing UINavigationController, because I need to use it in a subview. But I don't know how to set the rightBarButtonItem in a UINavigationController which is created programmatically.

navigationController.topViewController.navigationItem.rightBarButtonItem = cancelButton;

有人能说清楚这个吗？

提前致谢。

推荐答案

导航项目是每个视图控制器。导航栏从视图控制器的导航项中绘制其内容，该视图控制器的当前框架视图对应于导航控制器堆栈顶部的视图控制器。

The navigation item is per view controller. The navigation bar draws its contents from the navigation item of the view controller whose view it's currently framing, which corresponds to the view controller at the top of the navigation controller's stack.

您基本上需要每个视图控制器在其导航项中粘贴取消按钮。您可以执行以下任何操作：

You basically need each view controller to stick a cancel button in its navigation item. You can do any of the following:

• 将代码复制粘贴到所有相关的视图控制器中。


• 将代码移动到实用程序函数或类中并调用它。


• 为所有相关视图控制器创建一个公共超类，用于设置其子类的取消按钮。

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