iphone - 推送到导航栏的问题

Question

我有以下代码：

- (void)setupBook
{
    if (self.bookNavigationController) {
        BookViewController *bookVC = [[BookViewController alloc] initWithTemplate:x];
        self.myBookVC = bookVC;
        [bookVC release];    
        myBookVC.pageTitle = @"My Book";
        UINavigationController *nController = [[UINavigationController alloc] initWithRootViewController:myBookVC];
        self.bookNavigationController = nController;
        [nController release];
    }
}

然后在我拥有的代码的其他部分：

[self.someOtherNavigationController pushViewController:self.bookVC];

但是现在当我尝试将 self.bookNavigationController 呈现为模态视图控制器时，这是因为 myBookVC 不存在。为什么是这样？它只是显示一个带有导航栏的空视图。

Answer 1

何时首先创建视图控制器，您将其分配给属性，但是当分配为导航控制器的 rootViewController 时，您将引用 ivar。在分配 rootViewController 时使用该属性。

BookViewController *bookVC = [[BookViewController alloc] initWithTemplate:x];
bookVC.pageTitle = @"My Book";
self.myBookVC = bookVC;
[bookVC release];
UINavigationController *nController = [[UINavigationController alloc] initWithRootViewController:self.myBookVC];
self.bookNavigationController = nController;
[nController release];