ios - 使用第二个 UIViewController 启动 ViewPagerController

Question

我有一个 viewpagercontroller 并让它与 3 个预先设置的 UIViewController 一起正确运行，但是当我加载应用程序时它首先显示第一个 UIViewController，我想先显示第二个 UIViewController，但是我在实现这个时遇到了麻烦.

这是我的 ViewDidLoad()

override func viewDidLoad() {
    super.viewDidLoad()

    self.dataSource = self
    if let firstViewController = orderedViewControllers.first {
        setViewControllers([firstViewController],
                           direction: .forward,
                           animated: true,
                           completion: nil)
    }

}

这是我的 orderedViewControllers

private(set) lazy var orderedViewControllers: [UIViewController] = {
    return [self.newProfileViewController(vc: "UserContentViewController"),
            self.newProfileViewController(vc: "ProfileViewController"),
            self.newProfileViewController(vc: "NotificationViewController")]
}()

Answer 1

你可以用你想要的索引来实现这个功能，

func scrollToViewController(index newIndex: Int) {
    if let firstViewController = viewControllers?.first,
        let currentIndex = orderedViewControllers.indexOf(firstViewController) {
            let direction: UIPageViewControllerNavigationDirection = newIndex >= currentIndex ? .Forward : .Reverse
            let nextViewController = orderedViewControllers[newIndex]
            scrollToViewController(nextViewController, direction: direction)
    }
}