Question

所以我在加载时预选多个项目时遇到了一些麻烦。我的目标是让我的应用加载并让我cell当前所在的scroll bar完全预选。

我目前在它下面有一个图像图标和文字，问题是我的图标是预先选中并在开始时突出显示但是它下方的文字不是，除非我点击另一个单元格并单击原始单元格。所以我知道在swift 3.0中，代码看起来像预先选择我的图标但没有文字。我尝试了一些事情，但没有成功，所以这就是为什么我删除了尝试预先选择此代码中的文本的任何尝试。猜测大约四个小时，所以我想，而不是浪费另一天，我以为我会问！

    import UIKit

  class IntroBar: UIView, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {


    lazy var collectionView: UICollectionView = {
    let layout = UICollectionViewFlowLayout()
    let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
    cv.backgroundColor = .black
    cv.dataSource = self
    cv.delegate = self
    return cv
}()

let cellId = "cellId"
let imageNames = ["Ex1","Ex2","Ex3","Ex4"]
let titles = ["Ex1-1","Ex1-2","Ex1-3","Ex-1-4"]

var loginController: LoginController?


override init(frame: CGRect) {
    super.init(frame: frame)

    collectionView.register(MenuCell.self, forCellWithReuseIdentifier: cellId)

    addSubview(collectionView)
    addConstraintsWithFormat("H:|[v0]|", views: collectionView)
    addConstraintsWithFormat("V:|[v0]|", views: collectionView)


    let selectIndexPath = IndexPath(item: 0, section: 0)
    collectionView.selectItem(at: selectIndexPath, animated: false, scrollPosition: UICollectionViewScrollPosition())



    setupHorizontalBar()
}

var horizontalBarLeftAnchorConstraint: NSLayoutConstraint?

func setupHorizontalBar() {
    let horizontalBarView = UIView()
    horizontalBarView.backgroundColor = UIColor(white: 0.95, alpha: 1)
    horizontalBarView.translatesAutoresizingMaskIntoConstraints = false
    addSubview(horizontalBarView)

    horizontalBarLeftAnchorConstraint = horizontalBarView.leftAnchor.constraint(equalTo: self.leftAnchor)
    horizontalBarLeftAnchorConstraint?.isActive = true

    horizontalBarView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
    horizontalBarView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 1/4).isActive = true
    horizontalBarView.heightAnchor.constraint(equalToConstant:4).isActive = true
}

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    loginController?.scrollToMenuIndex(indexPath.item)
}

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return 4
}


func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! MenuCell

    cell.imageView.image = UIImage(named: imageNames[indexPath.item])?.withRenderingMode(.alwaysTemplate)

    cell.imageLabel.attributedText = NSMutableAttributedString(string: titles[indexPath.item], attributes: [NSFontAttributeName: UIFont.systemFont(ofSize: 10, weight: UIFontWeightHeavy), NSForegroundColorAttributeName: UIColor.black])
    cell.imageLabel.textAlignment = .center
    cell.tintColor = .darkGray

    return cell
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    return CGSize(width: frame.width / 4, height: frame.height)
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
    return 0
}


required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

}



class MenuCell: BaseCell {

let imageLabel: UILabel = {
    let label = UILabel()
   return label
}()

    let imageView: UIImageView = {
    let iv = UIImageView()
    iv.image = UIImage(named: "Ex1")?.withRenderingMode(.alwaysTemplate)
    iv.tintColor = .darkGray
    return iv
}()

override var isHighlighted: Bool {
    didSet {
        imageView.tintColor = isHighlighted ? .white : .darkGray
        imageLabel.textColor = isHighlighted ? .white : .black
    }
}

override var isSelected: Bool {
    didSet {
        imageView.tintColor = isSelected ? .white : .darkGray
        imageLabel.textColor = isSelected ? .white : .black
    }
}


    override func setupViews() {
        super.setupViews()

        addSubview(imageLabel)
        addSubview(imageView)
        addConstraintsWithFormat("H:[v0(33)]", views: imageView)
        addConstraintsWithFormat("V:[v0(33)]", views: imageView)
        addConstraintsWithFormat("H:[v0(75)]", views: imageLabel)
        addConstraintsWithFormat("V:[v0(50)]", views: imageLabel)

我为我粗略的编码黑客工作道歉......我刚刚开始几天前所以我真的只是试错了。此外，任何有关清理这些代码的见解都将非常感激!!

这就是它目前的出现方式

This is the start up with only icon preselected

This is when I switch to the 2nd icon

不允许我发布我的第三张图片，所以我希望图片一看起来像第二张图像，除了最初启动时。

Answer 1

在cellForItem方法中添加 cell.isSelected = true

此外，如果我需要手动选择单元格，我也可以使用cellForItem方法。因此，您不需要像您一样手动指定indexPath，因为您从方法本身获得了相应的indexPath。

将collectionView.selectItem(at: selectIndexPath, animated: false, scrollPosition: UICollectionViewScrollPosition())移动到要在渲染时选择的单元格。

func collectionView(_ collectionView: UICollectionView, cellForItemAt
                    indexPath: IndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, 
                                               for: indexPath) as! MenuCell

    cell.imageView.image = UIImage(named: imageNames[indexPath.item])?.withRenderingMode(.alwaysTemplate)

    cell.imageLabel.attributedText = ...
    cell.imageLabel.textAlignment = .center
    cell.tintColor = .darkGray

    if wantThisCellSelected == true {
       cell.isSelected = true
       collectionView.selectItem(at: indexPath, animated: false,
                                  scrollPosition: UICollectionViewScrollPosition())
    } else {
       cell.isSelected = false
       collectionView.deselectItem(at: indexPath, animated: false)
    }
      return cell
   }

预选单元格中的项目

1 个答案: