ios - UIBarbuttonItem 操作根本不起作用

Question

我有一个以下帮助程序类

class PDFPreviewHelper {
    var pdfNavigationController: UINavigationController!
    func previewButtonPressed(rootViewController: UIViewController) {
        let pdfViewController = PDFViewController(resource: "final.pdf")
        pdfNavigationController = UINavigationController(rootViewController: pdfViewController)

        let backButton = UIBarButtonItem(title: "Back", style: UIBarButtonItemStyle.Plain, target: self, action: "backButtonPressedInPDF")
        pdfViewController.navigationItem.setLeftBarButtonItem(backButton, animated: false)

        rootViewController.presentViewController(pdfNavigationController, animated: true, completion: nil)
    }



    func backButtonPressedInPDF() {
        pdfNavigationController.dismissViewControllerAnimated(true, completion: nil)
    }
}

我在 rootviewcontroller 中调用上述帮助器类中的函数，如下所示:

func previewInPdfButtonPressed() {
    let a = PDFPreviewHelper()
    a.viewI129InPDF(self)
}

我成功地在我的rootViewController之上以模态方式呈现pdfNavigationController，但是每当我按下后退按钮时，就不会调用任何内容。为什么会这样呢？我在 backButtonPressedInPDF 函数中设置了一个断点，但它甚至没有到达断点。

Answer 1

您需要通过以下方式将leftBarButtonItem分配给UINavigationController。

pdfViewController.navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Back", style: UIBarButtonItemStyle.Plain, target: self, action: "backButtonPressedInPDF")