使用 UICollectionViewCell 内的 Textfield 更新标签

Question

所以我在我的普通 ViewController 中有一个 CollectionView，如果我选择一个单元格并在我的 textField 中输入一些内容并按下保存按钮，它应该会更新 nameLabel 但我不知道该怎么做。有人对此有解决方案吗？

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，您需要做几件事。

首先，您需要通过存储“引用”来保留单击单元格的上下文。最简单的方法是引入三个新变量——section 和 item。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，不要调用dequeueReusableCellWithReuseIdentifier()，你应该使用上一步保存的值构造新的Index Path对象并调用cellForItemAtIndexPath(_ indexPath: NSIndexPath)。如果单元格不在视图中，这可能会返回 nil。

注意：这只会在用户点击保存时设置标签，如果单元格滚动出视图然后返回，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（部分语法可能不对，我是凭记忆做的）：

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
    }

}