UINavigationBarItem以编程方式 [英] UINavigationBarItem programmatically

问题描述

我有从 UINavigationController 继承的视图控制器。
在 viewDidLoad 上，我要设置 rightBarButtonItem 。
我会关注。

I have view controller which is inherited from UINavigationController. On viewDidLoad I want to set rightBarButtonItem. I do following.

UINavigationItem* navItem = self.navigationItem;
UIButton* btnOptionsView = [[UIButton alloc] init];
[btnOptionsView setImage:[UIImage imageNamed:@"options.png"]
                forState:UIControlStateNormal];
[btnOptionsView sizeToFit];
UIBarButtonItem* btnOptions = [[UIBarButtonItem alloc] initWithCustomView:btnOptionsView];
navItem.rightBarButtonItem = btnOptions;

但该按钮不可见，在调试模式下，我注意到 btnOptions。 width 为0，而且我无法为 navItem 设置标题，诸如此类

but the button is invisible, in debug mode I have noticed that btnOptions.width is 0, and also I can't set the title for navItem, something like this

[navItem setTitle:@"title"]

不会更改 UINavigationItem 的标题。

推荐答案

子类化UINavigationController。从苹果文档中获取：

You should not subclassing UINavigationController. From apple documentation:

UINavigationController类实现了专用视图
控制器，该控制器管理分层内容的导航。该
类不适用于子类化。而是在希望应用程序的用户
接口反映内容的层次结构的情况下，按原样使用
实例。

The UINavigationController class implements a specialized view controller that manages the navigation of hierarchical content. This class is not intended for subclassing. Instead, you use instances of it as-is in situations where you want your application’s user interface to reflect the hierarchical nature of your content.

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