通过 Collection View cell 在 ViewControllers 之间传递数据

Question

我有一个关于 UICollectionView 的相当基本的问题，并将数据传递给多个视图控制器，具体取决于按下的单元格。

在 ViewController.swift - 我拥有在控制器视图中显示单元格的所有代码。如您所见，我有一个小打印线测试，它告诉我哪个单元格（最终布局）被点击了。然后将我转到另一个由 uniqueViewController.swift 管理的视图控制器。

正是这个视图控制器 (uniqueViewController.swift) 我有一个标签 (uniqueLabel)，我希望根据从 ViewController 中单击的布局来更改文本。这是让我难过的整个数据传递部分。任何代码 sn-ps 和指导将不胜感激！谢谢。

ViewController.swift

import UIKit

class CollectionViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate  {


var data = [String]()


override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    data = ["Layout one", "Layout two", "Layout three", "Layout four"]


}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

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

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

    var btnLabel = cell.viewWithTag(1) as! UILabel
    btnLabel.text = data[indexPath.row]

    return cell
}

func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
    //println("Cell \(indexPath.row) tapped")
    performSegueWithIdentifier("testSegue", sender: self)

    if((indexPath.row) == 0) {
        println("Layout 1 clicked")

    }
    else if((indexPath.row) == 1) {
        println("Layout 2 clicked")
    }
    else if((indexPath.row) == 2) {
        println("Layout 3 clicked")
    }
    else if((indexPath.row) == 3) {
        println("Layout 4 clicked")
    }

}

}

uniqueViewController.swift

import UIKit

class uniqueViewController: UIViewController {

@IBOutlet weak var uniqueLabel: UILabel!

override func viewDidLoad() {
    super.viewDidLoad()

    uniqueLabel.text = "I want this labels text unique depending on which cell was tapped from ViewController.swift"

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

}

** 更新**

func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
    //println("Cell \(indexPath.row) tapped")
    performSegueWithIdentifier("testSegue", sender: indexPath.row)

}

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if let vc = segue.destinationViewController as? uniqueViewController {

        switch(sender as! Int) {
        case 0:
            vc.uniqueLabel.text = "First"
            break
        case 1:
            vc.uniqueLabel.text = "Second"
            break
        case 2:
            vc.uniqueLabel.text = "Third"
            break
        case 3:
            vc.uniqueLabel.text = "Fourth"
            break
        default:
            println("Index out of range.")
        }
    }
}

Answer 1

你应该在你的CollectionViewController中实现prepareForSegue

示例： 您必须在 uniqueViewController 中创建一个变量来保存从 prepareForSegue 分配的缓存字符串值

class uniqueViewController : UIViewController {
    var clickedCellValue: String!

    override func viewDidLoad(){
       super.viewDidLoad()

       uniqueLabel.text = clickedCellValue
    }
}

在您的 CollectionViewController 中，实现以下内容：

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let vc = segue.destinationViewController as? uniqueViewController {

            switch(sender as! Int) {
            case 0:
                vc.clickedCellValue = "First"
                break
            case 1:
                vc.clickedCellValue = "Second"
                break
            case 2:
                vc.clickedCellValue = "Third"
                break
            case 3:
                vc.clickedCellValue = "Fourth"
                break
            default:
                println("Index out of range.")
            }
        }
    }

为了能够检索点击的索引，请将indexPath.row 作为发件人传递：

performSegue("testSegue", sender: indexPath.row)

注意： 我并不是说您应该完全这样做，但这应该让您了解如何实现自己的解决方案。您可以将发送者传递给 uniqueViewController 并让控制器将索引转换为字符串，这取决于您如何构建数据源。

prepareForSegue(_:sender:)

希望这会有所帮助:)