如何向 UINavigationController 添加右键?

问题描述

我正在尝试将刷新按钮添加到导航控制器的顶部栏，但没有成功.

I am trying to add a refresh button to the top bar of a navigation controller with no success.

这是标题:

@interface PropertyViewController : UINavigationController {

}

这是我尝试添加它的方式:

Here is how I am trying to add it:

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
        UIBarButtonItem *anotherButton = [[UIBarButtonItem alloc] initWithTitle:@"Show" style:UIBarButtonItemStylePlain
                                          target:self action:@selector(refreshPropertyList:)];      
        self.navigationItem.rightBarButtonItem = anotherButton;
    }
    return self;
}

推荐答案

尝试在 viewDidLoad 中进行.一般来说，你应该尽可能推迟任何事情，直到那个时候，当 UIViewController 被初始化时，它可能还需要很长一段时间才能显示出来，提前工作和占用内存是没有意义的.

Try doing it in viewDidLoad. Generally you should defer anything you can until that point anyway, when a UIViewController is inited it still might be quite a while before it displays, no point in doing work early and tying up memory.

- (void)viewDidLoad {
  [super viewDidLoad];

  UIBarButtonItem *anotherButton = [[UIBarButtonItem alloc] initWithTitle:@"Show" style:UIBarButtonItemStylePlain target:self action:@selector(refreshPropertyList:)];          
  self.navigationItem.rightBarButtonItem = anotherButton;
  // exclude the following in ARC projects...
  [anotherButton release];
}

至于为什么它目前不工作，我不能在没有看到更多代码的情况下 100% 肯定地说，但是在 init 和视图加载之间发生了很多事情，你可能正在做一些导致 navigationItem 的事情在两者之间重置.

As to why it isn't working currently, I can't say with 100% certainty without seeing more code, but a lot of stuff happens between init and the view loading, and you may be doing something that causes the navigationItem to reset in between.

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