ios - +[UIView onBackgroundRequest :]: unrecognized selector sent to class

Question

部署目标:8.4 swift :2.0

我有一个 UIViewController 类，它有一个 UITableView 和一个 UIView 因为它是 tableHeaderView。 UIViewController 类有一个 UINotification 监听器，用作 tableHedearView 的 UIView 调度一个 UINotification。

我的 UIViewController 类相当简单。

StartViewController(UIViewController):

class StartViewController: UIViewController, UINavigationControllerDelegate
{
    @IBOutlet weak var tblContents: UITableView!

    override func viewDidLoad()
    {
        super.viewDidLoad()

        // table header view
        let headerView = StartTableHeaderView(frame: CGRectMake(0, 0, tblContents.bounds.width, self.view.frame.height*0.3))
        tblContents.tableHeaderView = headerView

        // adds notification listener
        NSNotificationCenter.defaultCenter().addObserver(self, selector: "onBackgroundRequested:", name: "changeBackground", object: nil)
    }

    func onBackgroundRequested(notification:NSNotification)
    {
        let uiImagePicker = UIImagePickerController()
        uiImagePicker.delegate = self
        uiImagePicker.sourceType = UIImagePickerControllerSourceType.PhotoLibrary

        self.presentViewController(uiImagePicker, animated: true, completion: nil)
    }
}

extension StartViewController: UIImagePickerControllerDelegate
{
    func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject])
    {
         ...
    }
}

StartTableHeaderView(UIView):

class StartTableHeaderView: UIView
{
    ...

    @IBAction func onBackgroundRequest(sender: AnyObject)
    {
        NSNotificationCenter.defaultCenter().postNotificationName("changeBackground", object: nil)
    }
}

在运行时，每当方法 (onBackgroundRequest) 在 StartTableHeaderView 中点击按钮时触发并分派(dispatch) UINotification，我会遇到以下错误:

2015-10-06 17:31:00.738 Elmo[1838:55864] +[UIView onBackgroundRequest:]: unrecognized selector sent to class 0x3272d90 2015-10-06 17:31:00.745 Elmo[1838:55864] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+[UIView onBackgroundRequest:]: unrecognized selector sent to class 0x3272d90'

Answer 1

StartTableHeaderView 类中调用 onBackgroundRequest: 的按钮上的操作是如何设置的？您是在使用 Interface Builder 还是在代码中进行操作？如果在代码中，您可以发布吗？

我认为您可能没有像您想象的那样发布通知。在 StartTableHeaderView onBackgroundRequest: 中放置一个断点，看看它是否曾经被触发。

错误告诉您未找到 onBackgroundRequest:，而不是 onBackgroundRequested:。