Question

我想做这样的事情。

（1）。如果我按下31中的那个按钮（A）之一，那个数字（A）就会变成红色。

（2）。然后如果我按下另一个按钮（B），然后（A）再次变黑，然后（B）变红。

**

class ViewController: UICollectionViewController {

var collectionViewCell = CollectionViewCell()
let data = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31]

override func viewDidLoad() {
    super.viewDidLoad()
    collectionView.register(UINib(nibName: "CollectionViewCell", bundle: nil), forCellWithReuseIdentifier : "MyCell")
}

override func numberOfSections(in collectionView: UICollectionView) -> Int {
    return 1
}
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return data.count
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "MyCell", for: indexPath) as! CollectionViewCell
        cell.Label.text = String(data[indexPath.row])
        return cell
}

}

  class CollectionViewCell: UICollectionViewCell {
@IBOutlet weak var Label: UILabel!
@IBOutlet weak var button: UIButton!

@IBAction func buttonPressed(_ sender: UIButton) {
    if Label.textColor == .red{
     Label.textColor = .black
    } else if Label.textColor == .black{
     Label.textColor = .red
    }
}

public override func awakeFromNib() {
    super.awakeFromNib()
}

}

Answer 1

您必须将所选单元格的行号保存在视图控制器中。

添加callback闭包而不是修改单元格中的颜色。在cellForRow中，通过重新加载行来处理回调，以将当前行设置为红色，将上一行设置为黑色。

类似这样的东西

class ViewController: UICollectionViewController {

    var selectedRow : Int?

    let data = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31]

    override func viewDidLoad() {
        super.viewDidLoad()
        collectionView.register(UINib(nibName: "CollectionViewCell", bundle: nil), forCellWithReuseIdentifier : "MyCell")
    }

    override func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 1
    }
    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return data.count
    }

    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "MyCell", for: indexPath) as! CollectionViewCell
        cell.Label.textColor = indexPath.item == selectedRow ? .red : .black
        cell.callback = { [unowned self] in
            if let row = self.selectedRow { 
                self.selectedRow = indexPath.item
                collectionView.reloadItems(at: [IndexPath(item: row, section: 0)])
            }
            cell.Label.textColor = .red
        }
        cell.Label.text = String(data[indexPath.row])
        return cell
     }
}

class CollectionViewCell: UICollectionViewCell {
    @IBOutlet weak var Label: UILabel!
    @IBOutlet weak var button: UIButton!

    var callback : (() -> Void)?

    @IBAction func buttonPressed(_ sender: UIButton) {
        callback?()
    }
}

Answer 2

您必须使用isSelected和func setSelected(_ selected: Bool, animated: Bool) {

但是首先您需要知道，在Swift中，我们对变量使用了camelCase样式。

现在，我们将不得不更改您的单元格实现：

class CollectionViewCell: UICollectionViewCell {
    @IBOutlet weak var label: UILabel!
    @IBOutlet weak var button: UIButton!

    public override func awakeFromNib() {
        super.awakeFromNib()
    }

    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)

        if selected {
            label.textColor = .red
        } else {
            label.textColor = .black
        }
    }

    @IBAction func buttonPressed(_ sender: UIButton) {
       self.isSelected = !self.isSelected
    }
}

也不要忘记将cell.Label.text = String(data[indexPath.row])更新为cell.label.text = String(data[indexPath.row])

编辑

Leo Darbus指出，使用isSelected.toggle()比self.isSelected = !self.isSelected更好，因为它已经由系统提供

我不知道要使（2）迅速工作，我需要做什么。

2 个答案: