objective-c – 来自DetailView的Swift导航中的UISplitViewController

2023年5月31日 138次阅读

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.但是,当我在iOS 7.1 iPad上试用它时出现了这个错误：

**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
}

问题来自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没有出现(在iOS 8模拟器上它确实如此)并且基本上没有导航到MasterView

有没有人有同样的问题？

谢谢！

最佳答案 您仍然可以在UISplitViewControllerDelegate中使用不推荐的回调函数来添加和删除UIBarButtonItem到IOS7平台的详细视图.在UISplitViewControllerDelegate中实现如下

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.
    }
}
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