Question

我有这个功能，我在我的应用程序中使用，创建一个全局函数会很好：

pc?.delegate = self

我遇到的问题是CustomReportVC。由于UIPopoverPresentationControllerDelegate符合func globalShowPicker(pickerValues:[String], field:UITextField, controller:UIViewController) -> AnyPickerVC{ //... pc?.delegate = controller //<-- ( ! ) Type UIViewController does not conform to UIPopoverPresentationControllerDelegate }，因此效果很好。

但是一旦我尝试将其创建为符合此协议的类之外的全局函数，我就会收到错误：

controller

我是UIViewController AnyObject还是// This works fine except the pnae is on the wrong place obviously .... Pane p = displayField.createDraggablePane(800.0, 800.0, 400.0, 300.0); rootView.getChildren().add(p); // Now the pane is in the right place, but it's 'stuck' .... rootView.setCenter(designView); Pane p = displayField.createDraggablePane(800.0, 800.0, 400.0, 300.0); designView.getChildren().add(p);，它不符合。有没有办法以某种方式将协议符合全局函数？

知道如何解决这个问题吗？谢谢。：）

Answer 1

使您的全局函数通用，以指定它仅适用于某些种类的UIViewControllers。在此示例中，T可以获取任何UIViewController类型的值，该类型也符合列出的其他协议。

func globalShowPicker< T: UIViewController where
    T: UIPopoverPresentationControllerDelegate,
    T: UIAdaptivePresentationControllerDelegate > 
    (pickerValues:[String], field:UITextField, controller: T) -> AnyPickerVC
{
   //...
   pc?.delegate = controller 

   return blah
}

它确实有点长，我还没有想出缩进所有约束的最佳方法。但它确实有效。

Answer 2

尝试添加一个继承自它们的新类。像这样。

class PopoverController: UIViewController, UIPopoverPresentationControllerDelegate {

}

然后，将功能切换为这样。

func globalShowPicker(pickerValues:[String], field:UITextField, controller: PopoverController) -> AnyPickerVC{
  //...
  pc?.delegate = controller  
}

Answer 3

这样的东西？

self.presentViewController(pc, animated: true, completion: nil)

顺便说一下，如果你在做Universal，你就不能像iPhone那样展示iPad UIActivityViewController。您需要按照Apple建议的设计指南在弹出窗口中显示它。

或作为示例

@IBAction func shareButtonClicked(sender: UIButton)
{
let textToShare = "Text"

if let myWebsite = NSURL(string: "http://www.example.com/")
{
    let objectsToShare = [textToShare, myWebsite]
    let activityVC = UIActivityViewController(activityItems:  objectsToShare, applicationActivities: nil)

    var nav = UINavigationController(rootViewController: activityVC)
    nav.modalPresentationStyle = UIModalPresentationStyle.Popover
    var popover = nav.popoverPresentationController as UIPopoverPresentationController!
    activityVC.preferredContentSize = CGSizeMake(500,600)
    popover.sourceView = self.view
    popover.sourceRect = CGRectMake(100,100,0,0)

    self.presentViewController(nav, animated: true, completion: nil)

}
}


class MyViewController : UIViewController,   UIPopoverPresentationControllerDelegate {
//code here
}

Answer 4

您可以将委托作为参数传递给函数，如下所示：

class CustomReportVC: UIViewController, UIAdaptivePresentationControllerDelegate, UIPopoverPresentationControllerDelegate {

    class func showPicker(pickerValues:[String], field:UITextField, delegate: UIPopoverPresentationControllerDelegate) -> UIViewController {
        //Set up modal
        let storyboard = UIStoryboard(name: "Popovers", bundle: nil)
        let modal = storyboard.instantiateViewControllerWithIdentifier("AnyPickerModal") as! UIViewController
        modal.modalPresentationStyle = UIModalPresentationStyle.Popover
        let pc = modal.popoverPresentationController
        pc?.permittedArrowDirections = .Down
        pc?.sourceView = field
        pc?.sourceRect = field.bounds
        modal.preferredContentSize = CGSizeMake(300,180)
        pc?.delegate = delegate

        //Pass in data
        modal.data = pickerValues

        //Set the value from within the picker controller
        modal.passDataToParent = { (value) in
            field.text = value
        }

        return modal
    }

    //Required for the popover
    func adaptivePresentationStyleForPresentationController(controller: UIPresentationController) -> UIModalPresentationStyle {
        return .None
    }

}

最后你有一个符合协议的视图控制器实例，但是这样你就可以像你想要的那样拥有全局函数，并在符合协议的视图控制器中传递自我指针＆＃34; UIPopoverPresentationControllerDelegate＆＃34;：

CustomReportVC.showPicker(pickerValues:....., delegate: self)

iOS 8上的Swift 1.2中的全局弹出功能

4 个答案: