swift - CollectionView selectItem TintColor 未突出显示或选择该项目

Question

我在MenuClass中有这个 Collection View 如下:

class MenuBar: UIView, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {
    lazy var collectionView: UICollectionView = {
        let layout = UICollectionViewFlowLayout()
        let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
        cv.backgroundColor = UIColor.rgb(colorLiteralRed: 230, green: 32, blue: 31, alpha: 1)
        cv.dataSource = self
        cv.delegate = self
        return cv
    }()

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

        addSubview(collectionView)
        collectionView.register(MenuCell.self, forCellWithReuseIdentifier: cellId)
        //NOT WORKING
        let selectIndexPath = IndexPath(item: 0, section: 0)
        collectionView.selectItem(at: selectIndexPath, animated: false, scrollPosition: [])

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

        backgroundColor = UIColor.rgb(colorLiteralRed: 230, green: 32, blue: 31, alpha: 1)
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! MenuCell
        cell.imageView.image = UIImage(named: imageName[indexPath.row])?.withRenderingMode(UIImageRenderingMode.alwaysTemplate)
        cell.imageView.tintColor = UIColor.rgb(colorLiteralRed: 91, green: 14, blue: 13, alpha: 1)
        return cell
    }
}

这是MenuCell我为上面的 Collection View 注册的类:

class MenuCell: BaseCell {

    let imageView: UIImageView = {
        let iv = UIImageView()
        return iv
    }()


    override var isHighlighted: Bool {
        didSet {
            imageView.tintColor = isHighlighted ? UIColor.white : UIColor.rgb(colorLiteralRed: 91, green: 14, blue: 13, alpha: 1)
        }
    }

    override var isSelected: Bool {
        didSet {
            imageView.tintColor = isSelected ? UIColor.white : UIColor.rgb(colorLiteralRed: 91, green: 14, blue: 13, alpha: 1)
        }
    }

    override func setUpViews() {
        super.setUpViews()
        addSubview(imageView)
        addConstraintsWithFormat(format: "H:[v0(28)]", views: imageView)
        addConstraintsWithFormat(format: "V:[v0(28)]", views: imageView)

        addConstraint(NSLayoutConstraint(item: imageView, attribute: .centerX, relatedBy: .equal, toItem: self, attribute: .centerX, multiplier: 1, constant: 0))
        addConstraint(NSLayoutConstraint(item: imageView, attribute: .centerY, relatedBy: .equal, toItem: self, attribute: .centerY, multiplier: 1, constant: 0))
    }
}

我的问题是在 MenuBar init 内这些代码行中的类方法:

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

它没有选择 Collection View 的第一项并将其突出显示为白色作为默认选定的项目。我认为这与这一行有关:cell.imageView.tintColor = UIColor.rgb(colorLiteralRed: 91, green: 14, blue: 13, alpha: 1)里面cellForItemAt MenuBar中的方法以及 isSelected 内的覆盖属性( isHighLighted 和 MenuCell ) .

我不确定这种着色如何在 imageView 上发挥作用。 (我在 MenuCell 上定义)或者我是否正确使用了属性。有人可以让我知道如何使用着色和属性来实现这一目标。主页按钮突出显示为白色:

Answer 1

好的，我在 MenuBar 的 cellForItemAt 方法中更改了这一行:

cell.imageView.image = UIImage(命名: imageName[indexPath.row])?.withRenderingMode(UIImageRenderingMode.alwaysTemplate)

至:

cell.image = UIImage(命名: imageName[indexPath.row])?.withRenderingMode(UIImageRenderingMode.alwaysTemplate)

通过删除该 imageView 并由于某种原因它修复了问题并现在默认选择第一项。谁能告诉我为什么这有效？