ios - 使用 UICollectionViewCell 内的 Textfield 更新标签

Question

所以我在普通的 ViewController 中有一个 CollectionView，如果我选择一个单元格并在文本字段中输入一些内容并按保存按钮，它应该更新 nameLabel 但我不知道如何做到这一点。有人有解决办法吗？

这是我当前的代码:

    private let reuseIdentifier: String = "Item"

class ViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate, UIGestureRecognizerDelegate, UITextFieldDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        ItemCollection.delegate = self
    }



    func textEnter() {
        var text = textField.text

        let indexPath = NSIndexPath()
        let cell = ItemCollection.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath) as! ItemCell

        cell.nameLabel.text = text

    }

    @IBAction func save(sender: AnyObject, cell: UICollectionViewCell) {
        textEnter()
    }

    @IBOutlet weak var textField: UITextField!
    @IBOutlet weak var ItemCollection: UICollectionView!


    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 2
    }

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

        cell.backgroundColor = UIColor(red: 0/256, green: 128/256, blue: 255/256, alpha: 0.66)
        cell.nameLabel.text = "Test1"
        return cell
    }

    func collectionView(collectionView: UICollectionView, shouldSelectItemAtIndexPath indexPath: NSIndexPath) -> Bool {
        return true
    }

}

我的手机:

class ItemCell: UICollectionViewCell {

    @IBOutlet weak var nameLbl: UILabel!

}

Answer 1

要完成这项工作，您需要做一些事情。

首先，您需要通过存储对其的“引用”来保留单击单元格的上下文。最简单的事情是引入三个新变量 - 部分和项目。使用这些值，您将能够重新创建索引路径对象并引用单元格。

其次，您应该使用上一步中保存的值构造新的 Index Path 对象并调用 cellForItemAtIndexPath(_indexPath: NSIndexPath)，而不是调用 dequeueReusableCellWithReuseIdentifier()。如果单元格不在 View 中，这可能会返回零。

注意:仅当用户点击“保存”时才会设置标签，如果单元格滚动到 View 之外然后再返回，文本很可能会丢失。为了保留这一点，您应该在 cellForItemAtIndexPath 方法中创建单元格时将输入的值存储在变量中(或直接引用文本框)。

修改后的代码示例(某些语法可能不正确，我是凭内存这样做的):

private let reuseIdentifier: String = "Item"

class ViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate, UIGestureRecognizerDelegate, UITextFieldDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        ItemCollection.delegate = self
    }

    // Store the clicked item location
    private section: Int = 0
    private item: Int = 0

    func textEnter() {
        var text = textField.text

        let indexPath = NSIndexPath(forItem: item inSection:section)
        let cell = ItemCollection.cellForItemAtIndexPath(indexPath) as! ItemCell

        cell.nameLabel.text = text
    }

    @IBAction func save(sender: AnyObject, cell: UICollectionViewCell) {
        textEnter()
    }

    @IBOutlet weak var textField: UITextField!
    @IBOutlet weak var ItemCollection: UICollectionView!

    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 2
    }

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

        cell.backgroundColor = UIColor(red: 0/256, green: 128/256, blue: 255/256, alpha: 0.66)
        cell.nameLabel.text = "Test1"
        return cell
    }

    // Need to capture the tapped cell in here
    func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
        section = indexPath.section
        item = indexPath.item
    }

    func collectionView(collectionView: UICollectionView, shouldSelectItemAtIndexPath indexPath: NSIndexPath) -> Bool {
        return true
    }

}