ios - 隐藏导航控制器的 rightBarButtonItem

Question

有谁知道如何隐藏 arightBarButtonItem的 a UINavigationController？rightBarButtonItem在我的应用程序中，我有一个编辑按钮作为UINavigationController. 我想隐藏这个？完成某些操作时的 UIBarButton`。

Answer 1

To Hide the right button: self.navigationItem.rightBarButtonItem = nil;

Now, to show it:

1. If you setup the right button in your view controller by assigning it to self.editButtonItem then simply assign it again in order to show it:

   self.navigationItem.rightBarButtonItem = self.editButtonItem;

2. If you setup the right button in your view controller by allocating and initing a UIBarButtonItem, then simply keep a reference to the UIBarButtonItem in your view controller, and assign it again when you need to show it.

Answer 2

尝试

self.navigationItem.rightBarButtonItem = nil;

当你想要它回来时，你将不得不实例化一个按钮，即

UIBarButtonItem *rightBarButton = 
 [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemSearch
                                               target:self
                                               action:@selector(searchBar:)];
self.navigationItem.rightBarButtonItem = rightBarButton;
[rightBarButton release];

Answer 3

如果您需要根据某些条件隐藏/显示按钮，请尝试以下操作：

if (condition) { 
    self.navigationItem.rightBarButtonItem.title = @"";
    self.navigationItem.rightBarButtonItem.enabled = NO;
} else {
    self.navigationItem.rightBarButtonItem.title = @"my button title";
    self.navigationItem.rightBarButtonItem.enabled = YES;
}

这样您就不必在属性中保存对按钮的引用，也不必担心在新按钮上连接操作。