ios - 在方向更改时重新加载 UIPageViewController View

Question

对于我正在构建的应用程序，我在 UIView 中有一个 UIPageViewController，它具有 Transition Style = Scroll。每个页面都有相同的 UITableViewController 类(当然有不同的数据)。此时一切正常。

现在我想要根据设备的方向使用 UITableViewController 的横向版本或纵向版本。为此，我实现了一个 NSNotification，其中包含一个在方向更改 (orientationChanged) 时调用的方法，这也有效。但是从这里出现了一个问题，当改变设备的方向时，我不确定如何加载正确的 UITableViewController 实例。如您所见，我正在使用 UIPageViewControllerDataSource 的委托(delegate)方法 viewControllerAtIndex，我在其中确保启动 viewController 的横向或纵向版本。

问题是，当改变设备的方向时，正确的 UITableViewController 只有在向左/向右滑动几页后才会加载。我一定是忽略了一些简单的东西，但似乎找不到它!

我有以下代码片段，我认为其中的问题是:

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Create the data model
    _pageTitles = @[@"1",@"2",@"3",@"4",@"5"];
    _pageTables = @[@"test1",@"test2",@"test3",@"test4",@"test5"];

    // Create page view controller
    self.weightPageViewController = [self.storyboard instantiateViewControllerWithIdentifier:@"WeightPageViewController"];
    self.weightPageViewController.dataSource = self;

    WeightPageContentViewController *startingViewController = [self viewControllerAtIndex:0];
    NSArray *viewControllers = @[startingViewController];
    [self.weightPageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil];

    [self addChildViewController:_weightPageViewController];
    [self.view addSubview:_weightPageViewController.view];
    [self.weightPageViewController didMoveToParentViewController:self];

    self.edgesForExtendedLayout = UIRectEdgeNone;

    //Register for device orientation changes.
    [[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(orientationChanged:) name:@"UIDeviceOrientationDidChangeNotification" object:nil];
}

- (void) orientationChanged:(id)object {
    [self viewControllerAtIndex:0];
}

- (WeightPageContentViewController *)viewControllerAtIndex:(NSUInteger)index
{
    if (([self.pageTitles count] == 0) || (index >= [self.pageTitles count])) {
        return nil;
    }

    UIDeviceOrientation deviceOrientation = [UIDevice currentDevice].orientation;
    if (UIDeviceOrientationIsLandscape(deviceOrientation)) {
        NSLog(@"Orientation is now Landscape);
        // Create a new view controller and pass suitable data.
        WeightPageContentViewController *weightPageContentViewController = [self.storyboard instantiateViewControllerWithIdentifier:@"WeightPageContentViewControllerLandscape"];
        weightPageContentViewController.tableText = self.pageTables[index];
        weightPageContentViewController.titleText = self.pageTitles[index];
        weightPageContentViewController.pageIndex = index;
        return weightPageContentViewController;
    } else if (deviceOrientation == UIDeviceOrientationPortrait) {
        NSLog(@"Orientation is now Portrait);
        // Create a new view controller and pass suitable data.
        WeightPageContentViewController *weightPageContentViewController = [self.storyboard instantiateViewControllerWithIdentifier:@"WeightPageContentViewController"];
        weightPageContentViewController.tableText = self.pageTables[index];
        weightPageContentViewController.titleText = self.pageTitles[index];
        weightPageContentViewController.pageIndex = index;
        return weightPageContentViewController;
    } else {
        NSLog(@"Orientation is now unknown);
        // Create a new view controller and pass suitable data.
        WeightPageContentViewController *weightPageContentViewController = [self.storyboard instantiateViewControllerWithIdentifier:@"WeightPageContentViewController"];
        weightPageContentViewController.tableText = self.pageTables[index];
        weightPageContentViewController.titleText = self.pageTitles[index];
        weightPageContentViewController.pageIndex = index;
        return weightPageContentViewController;
    }
}

Answer 1

每次方向改变你都需要重新设置 View Controller

WeightPageContentViewController *startingViewController = [self viewControllerAtIndex:currentViewControllerIndex];
NSArray *viewControllers = @[startingViewController];
[self.weightPageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil];