Question

我是Swift的初学者。

我的CollectionView中有UIViewController，我需要在用户点击CollectionViewCell到另一个ViewController时传递数据。我试图覆盖prepareForSegue，但我注意到它先调用didSelectItemAtIndexPath上的代码。

我的第一个ViewController代码：

import UIKit

class ViewController: UIViewController {

    ...

    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

extension ViewController : UICollectionViewDataSource,UICollectionViewDelegate{

    func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
        return 1
    }

    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return items.count
    }

    func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier("collCell", forIndexPath: indexPath) as! MainCollectionViewCell

        ...
        return cell
    }

    func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {

        itemId = items[indexPath.item].id

        let distinationViewController = DistinationViewController()
        distinationViewController.itemId = itemId
    }   
}

我的Distination视图控制器代码

import UIKit

class DistinationViewController: UIViewController{

    var itemId : String!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        print(itemId)
    }
}

itemId中DistinationViewController的值为nil

由于

Answer 1

您可以尝试通过以下代码更改视图：

func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
        itemId = items[indexPath.item].id
        let distinationViewController = self.storyboard.instantiateViewControllerWithIdentifier("DestinationViewControllerStoryBoardID") as! DistinationViewController

        distinationViewController.itemId = itemId
self.navigationController.pushViewController(distinationViewController, animated: true)
}

Answer 2

你需要做两件事：

将您的func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath)更改为以下内容之一：

    func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {

        // Here you can check which Collection View is triggering the segue
        if collectionView == collectionView1 {
            self.performSegueWithIdentifier("fromFirstCollectionView", sender: nil);
        } else if collectionView == collectionView2 {
            // from other CollectionView
        }
    }

并且您的prepareForSegue方法将是这样的

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

        // Even here you can check for segue.identifiers if you have something to differentiate
        let dvc = segue.destinationViewController as! DestinationViewController
        dvc.itemId = "Hello"
    }

从View Controller连接segue并为其指定identifier

根据您的评论，您有3个collectionView，所以我猜您需要3个带有3个不同标识符的segue。

希望这有帮助！很高兴讨论你是否有更多问题。

Answer 3

您可以将所有内容放入prepareForSegue中。像这样：

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if let identifier = segue.identifier{
        switch identifier {
            case "distinationViewController":
                if let nextScene =  segue.destinationViewController as? DistinationViewController {
                    if let indexPath = self.collectionView.indexPathsForSelectedItems.lastItem {
                        nextScene.itemId=items[indexPath.item].id
                        nextScene.delegate = self
                }
            }
            default: break
        }
    }
}

将数据从CollectionView Delegate传递到另一个ViewController

3 个答案: