objective-c - 从 DetailView 快速导航中的 UISplitViewController

Question

我正在尝试在 Swift 中创建一个 MasterDetail 应用程序，它在 iOS8 模拟器上运行良好。然而，当我在我的 iOS 7.1 iPad 上尝试时，我得到了这个错误:

**Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-    [UISplitViewController displayModeButtonItem]: unrecognized selector sent to instance**

这是在我的 AppDelegate.swift 文件中(由 Xcode 生成，我没有添加任何内容):

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    // Override point for customization after application launch.
    let splitViewController = self.window!.rootViewController as UISplitViewController
    let navigationController = splitViewController.viewControllers[splitViewController.viewControllers.count-1] as UINavigationController
    navigationController.topViewController.navigationItem.leftBarButtonItem = splitViewController.displayModeButtonItem()
    splitViewController.delegate = self

    let masterNavigationController = splitViewController.viewControllers[0] as UINavigationController
    let controller = masterNavigationController.topViewController as MasterViewController
    controller.managedObjectContext = self.managedObjectContext
    return true
}

问题出在创建左按钮的这一行:

navigationController.topViewController.navigationItem.leftBarButtonItem = splitViewController.displayModeButtonItem()

当我删除此行时，它在 iOS 7 上运行但仅显示 DetailView。当我从左边缘滑动时，MasterView 不会出现(在 iOS 8 模拟器上会出现)并且基本上没有到 MasterView 的导航

有人遇到同样的问题吗？

谢谢!

Answer 1

您仍然可以在 UISplitViewControllerDelegate 中使用已弃用的回调函数来添加和删除 UIBarButtonItem 到您的 IOS7 平台的详细 View 。在您的 UISplitViewControllerDelegate 中实现如下所示

func splitViewController(svc: UISplitViewController, willHideViewController aViewController: UIViewController, withBarButtonItem barButtonItem: UIBarButtonItem, forPopoverController pc: UIPopoverController) {
    if !self.respondsToSelector(Selector("displayModeButtonItem")) {
        let navigationController = self.viewControllers.last as! UINavigationController
        let detailViewController: UIViewController? = navigationController.viewControllers?.last as? UIViewController
        barButtonItem.image = UIImage(named: "IC_BackArrow")
        detailViewController?.navigationItem.leftBarButtonItem = barButtonItem
    } else {
        // This callback function is depreciated in IOS8. We use displayModeButtonItem.
    }
}

func splitViewController(svc: UISplitViewController, willShowViewController aViewController: UIViewController, invalidatingBarButtonItem barButtonItem: UIBarButtonItem) {
    if !self.respondsToSelector(Selector("displayModeButtonItem")) {
        let navigationController = self.viewControllers.last as! UINavigationController
        let detailViewController: UIViewController? = navigationController.viewControllers?.last as? UIViewController
        detailViewController?.navigationItem.leftBarButtonItem = nil
    } else {
        // This callback function is depreciated in IOS8. We use displayModeButtonItem.
    }
}