將數據從CollectionView委托傳遞到另一個ViewController

Question

我是Swift的初學者。

我的UIViewController有CollectionView ，當用戶單擊CollectionViewCell到另一個ViewController時，我需要傳遞數據。 我嘗試覆蓋prepareForSegue但我注意到它先調用，然后在didSelectItemAtIndexPath上進行編碼。

我的第一個ViewController代碼：

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視圖控制器代碼

import UIKit

class DistinationViewController: UIViewController{

    var itemId : String!

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

DistinationViewController中itemId的DistinationViewController nil

謝謝

Answer 1

您可以嘗試通過以下代碼更改視圖：

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

您需要做兩件事：

1. 將您的func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath)更改為以下內容：

     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 } } 

   您的prepareForSegue方法將如下所示

    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" } 

2. 從View Controller連接segue並為其分配identifier

根據您的評論，您有3個collectionView所以我想您需要3個帶有3個不同標識符的segue。

希望這可以幫助！ 如果您還有其他問題，很高興與您討論。

Answer 3

您可以將所有內容都放入prepareForSegue中。 像這樣：

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
        }
    }
}