ios - SWIFT：在 TVOS 中退出收集时强制焦点引擎转到按钮

Question

我已经以编程方式实现了这个：

1. tableView 单元格列表。
2. 每个 tableViewCell 都包含一个 collectionView 和一个 Button。

现在发生了什么事：

1. 焦点引擎在集合视图上
2. 用户向下滚动
3. 除非我在焦点集合视图的最后一项上，否则焦点引擎会转到下一个集合视图，然后它会转到 VoirTout 按钮。

我想要的是：

1. 焦点引擎在集合视图上
2. 用户向下滚动
3. 焦点引擎转到 Voir Tout 按钮

我已经看到了几个使用preferredFocusEnvironments这样的答案：

 // Trying to force focus on button
    var voirToutButton:  CustomButton? = CustomButton(color: .red, titleString: "");
    override var preferredFocusEnvironments : [UIFocusEnvironment] {
        return [voirToutButton!]
    }

然后在 viewDidLoad 中调用这些：

 // TRYING TO FORCE FOCUS ON VOIR TOUT BUTTON
setNeedsFocusUpdate()
updateFocusIfNeeded()

但是，就我而言，这没有效果。

Answer 1

我是这样解决的。我不确定这是最理想的方式，但它确实有效：

class TableViewCell: UITableViewCell {

    var voirToutButton:  CustomButton? = CustomButton(color: .red, titleString: "");
    var shouldRefocusToVoirToutButton:Bool = false
    override var preferredFocusEnvironments : [UIFocusEnvironment] {
            return [voirToutButton!]
    }
    override func shouldUpdateFocus(in context: UIFocusUpdateContext) -> Bool {
        if (self.shouldRefocusToVoirToutButton){
            // Resetting this to false in order to avoid the focus getting stuck on voirToutButton
            self.shouldRefocusToVoirToutButton = false
                    self.setNeedsFocusUpdate()
                   self.updateFocusIfNeeded()
        }
        return true
        
    }
}

extension TableViewCell: UICollectionViewDelegate, UICollectionViewDataSource {

    func collectionView(_ collectionView: UICollectionView, shouldUpdateFocusIn context: UICollectionViewFocusUpdateContext) -> Bool {
       
        if let previouslyFocusedItemParent =  context.previouslyFocusedItem?.parentFocusEnvironment as? UICollectionView, let nextFocusedItemParent = context.nextFocusedItem?.parentFocusEnvironment as? UICollectionView  {
          
 let isPreviousFocusInCurrentCollectionView = previouslyFocusedItemParent == self.moviesCollectionView
        let isNextFocusInCurrentCollectionView = nextFocusedItemParent == self.moviesCollectionView
        let isFocusLeavingCollectionView = !(isPreviousFocusInCurrentCollectionView == isNextFocusInCurrentCollectionView)
        let isFocusMovingDown:Bool =  !(context.focusHeading == .up)
        if (isFocusLeavingCollectionView && isFocusMovingDown) {
            self.shouldRefocusToVoirToutButton = true
        }
        return true
        }
            // I remove this else it says that I need to return a bool (!(
        else {
            print("If I remove this else it says that I need to return a bool (!(")
            return true
        }
    }
    
}