Question

我在一个类Main_Screen中有一个IBOutlet，它可以连接到一个主ViewController，它有一个ScrollView，但是如果我尝试得到它则返回nil

视图控制器中的

代码

import UIKit

class ViewController: UIViewController , UIScrollViewDelegate {

    @IBOutlet weak var scrollVieww: UIScrollView!

    override func viewDidLoad() {
         super.viewDidLoad()

      self.scrollVieww.pagingEnabled = true
      self.scrollVieww.delegate = self

        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        if let vc = storyboard.instantiateViewControllerWithIdentifier("MainScreen") as? Main_Screen {
            // imageview returns nil :(
            let imageView = vc.avatarImageView
        }

      // Do any additional setup after loading the view, typically from a nib.
        let V1 = self.storyboard?.instantiateViewControllerWithIdentifier("HomeScreen") as UIViewController!
        //Add initialized view to main view and its scroll view and also set bounds
        self.addChildViewController(V1)
        self.scrollVieww.addSubview(V1.view)
        V1.didMoveToParentViewController(self)
        V1.view.frame = scrollVieww.bounds

        //Initialize using Unique ID for the View
        let V2 = self.storyboard?.instantiateViewControllerWithIdentifier("MainScreen") as UIViewController!
        //Add initialized view to main view and its scroll view also set bounds
        self.addChildViewController(V2)
        self.scrollVieww.addSubview(V2.view)
        V2.didMoveToParentViewController(self)
        V2.view.frame = scrollVieww.bounds

        //Create frame for the view and define its urigin point with respect to View 1
        var V2Frame: CGRect = V2.view.frame
        V2Frame.origin.x = self.view.frame.width
        V2.view.frame = V2Frame

      //The width is set here as we are dealing with Horizontal Scroll
        //The Width is x3 as there are 3 sub views in all
        self.scrollVieww.contentSize = CGSizeMake((self.view.frame.width) * 2, (self.view.frame.height))

 }

Answer 1

简短的回答：不要这样做。您应该将另一个视图控制器的视图视为私有。

如果您需要操纵另一个视图控制器的UI，请添加用于请求更改UI的公共方法，然后让VC中的代码进行更改。

这是更好的设计，它避免了其他视图控制器的视图尚未被创建的情况，所以它们没有，并且它失败/崩溃与＃34 ;在试图打开可选的＆＃34;时遇到nil;消息。

从另一个班级迅速获得IBOutlet

1 个答案: