Question

我无法弄清楚如何在UIPageViewController中的UIViewControllers之间保存/传递数据。我的设置是这样的：

#pragma mark - UIPageViewControllerDataSource

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
{

    //This is nice and avoids having to use a counter
    NSString *vcRestorationID = viewController.restorationIdentifier;
    NSUInteger index = [self.controllerRestorationIDs indexOfObject:vcRestorationID];

    if (index == 0) {
        return nil;
    }

    return [self viewControllerAtIndex:index - 1];
}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
    NSString *vcRestorationID = viewController.restorationIdentifier;
    NSUInteger index = [self.controllerRestorationIDs indexOfObject:vcRestorationID];

    //Don't allow it to go forward if there is one at the end
    if (index == self.controllerRestorationIDs.count - 1) {
        return nil;
    }

    return [self viewControllerAtIndex:index + 1];
}


#pragma mark - Private Methods

- (UIViewController *)viewControllerAtIndex:(NSUInteger)index
{
    // Only process a valid index request.
    if (index >= self.controllerRestorationIDs.count) {
        return nil;
    }

    // Create a new view controller.
    //Note this is just an extension of UIViewController with a variable inside. All my view controllers in this must be subclassed off BaseContentViewController
    BaseContentViewController *contentViewController = (BaseContentViewController *)[self.storyboard instantiateViewControllerWithIdentifier:self.controllerRestorationIDs[index]];

    // Set any data needed by the VC here
    contentViewController.rootViewController = self;

    return contentViewController;

}

这是在我的RootViewController.m（包含UIPageViewController的控制器）中。我需要做的是在刷新新控制器时，在当前显示的控制器中保存变量或数据。我是否需要使用单身或其他东西？

Answer 1

尝试在* ViewController中使用NSNotificationCenter类

Answer 2

NSNotificationCenter可能是您最快的实现，如果您只需要来回传递小块信息，并且需要同时向多个目的地传递信息。如果在更可能的情况下，您需要经常更新信息并仅在必要时引用它，那么单例将是一个更实用的解决方案。

单身人士非常容易使用和实施。 A quick google search had this walkthrough as the first result。这将向您展示如何设置它，并且使用它非常类似于在视图控制器中使用任何其他属性。

可能需要花费几分钟的时间来运行NSNotificationCenter，但它更具可扩展性，可读性和可维护性。

我应该如何在UIPageViewController中的UIViewControllers之间传递数据并保存变量

2 个答案: