向左或向右滑动即可将集合视图单元格突出显示加载到视图控制器中

Question

我有3个称为的视图控制器firstvc, secondvc, thirdvc。我有一个集合视图，它将水平滚动。如果我选择我的first cell我firstvc的我的我的子画面WIL DISPLY mainviewcontroller。它同样为2, 3rd cell过。没关系
。

现在，我需要一种功能，例如，如果subview我在选择任何单元格时滑动我的所有视图控制器，它将具有所有视图控制器。我需要向左或向右滑动。

例如 ：

如果我参加的firstvc话，我first cell会被 选中
。现在，如果我subview从右向右滑动，我secondvc必须要刻薄，而第二个集合视图单元也必须highlight

我不知道如何申请。

我的代码：

  @IBOutlet weak var collectionview: UICollectionView!

    @IBOutlet weak var contentSubView: UIView!
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return self.items.count
    }

    // make a cell for each cell index path
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

        // get a reference to our storyboard cell
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath as IndexPath) as! MyCollectionViewCell

        // Use the outlet in our custom class to get a reference to the UILabel in the cell
        cell.myLabel.text = self.items[indexPath.item]
       // cell.backgroundColor = UIColor.cyan // make cell more visible in our example project

        var borderColor: UIColor! = UIColor.clear
        //var borderWidth: CGFloat = 0

        if indexPath == selectedIndexPath{
            borderColor = UIColor.red
            //borderWidth = 1 //or whatever you please
        }else{
            borderColor = UIColor.white
           // borderWidth = 0
        }

        cell.myview.backgroundColor = borderColor
       // cell.myview.layer.borderWidth = borderColor

        return cell
    }


    // MARK: - UICollectionViewDelegate protocol

    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        print("You selected cell #\(indexPath.item)!")

        //based on your comment remove the subviews before add on your myview
        //let cell = collectionView.cellForItemAtIndexPath(indexPath) as! MyCollectionViewCell

        selectedIndexPath = indexPath

        for subview in contentSubView.subviews {
            subview.removeFromSuperview()
        }

        let alertStoryBoard =  UIStoryboard(name: "Main", bundle: nil)
        var controller: UIViewController!

        if indexPath.item == 0 {

            if  let allCollectionViewController = alertStoryBoard.instantiateViewController(withIdentifier:"firstvc") as? firstvc  {

                controller = allCollectionViewController
            }

        } else if indexPath.item == 1 {

            if  let allCollec = alertStoryBoard.instantiateViewController(withIdentifier:"secondvc") as? secondvc  {
                controller = allCollec
            }


        }else if indexPath.item == 2 {


            if  let wController = alertStoryBoard.instantiateViewController(withIdentifier:"Thirdvc") as? Thirdvc  {
                controller = wController
            }

        }

        addChildViewController(controller)

        // Add the child's View as a subview
        contentSubView.addSubview(controller.view)
        controller.view.frame = contentSubView.bounds
        controller.view.autoresizingMask = [.flexibleWidth, .flexibleHeight]

        // tell the childviewcontroller it's contained in it's parent
        controller.didMove(toParentViewController: self)

}

我的完整项目zip：https
:
//www.dropbox.com/s/fwj745kdgqvgjxa/Collection%20view%20example.zip?
dl
=0

Answer 1

您应该只添加UISwipeGestureRecognizer到主视图控制器的视图。主视图控制器将负责管理手势的调用

基本上在代码中：

在viewDidLoad：

let swipeToLeft = UISwipeGestureRecognizer(target: self, action: #selector(changePageOnSwipe(_:)))
let swipeToRight = UISwipeGestureRecognizer(target: self, action: #selector(changePageOnSwipe(_:)))
swipeToLeft.direction = .right 
swipeToRight.direction = .left
self.contentSubView.addGestureRecognizer(swipeToLeft) // Gesture are added to the top view that should handle them
self.contentSubView.addGestureRecognizer(swipeToRight)

由于您必须从索引的VC移到另一个索引，因此可能需要一个属性来跟踪当前选定的视图控制器：

var currentIndexPath: IndexPath?

您可以在每次选择新的VC时更改其值。所以：

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    print("You selected cell #\(indexPath.item)!")
    self.currentIndexPath = indexPath
    // ... Other settings
}

changePageOnSwipe(_ gesture: UISwipeGestureRecognizer)在您的主ViewController中添加方法。由于拥有的是“首席”视图控制器collectionView，因此它将处理滑动并告诉其子代出现：

func changePageOnSwipe(_ gesture: UISwipeGestureRecognizer) {
    guard let indexPath = self.currentIndexPath else {
        // When the page loads and there is no current selected VC, the swipe will not work
        // unless you set an initial value for self.currentIndexPath
        return
    }

    var newIndex = indexPath    // if self.collectionview.indexPathsForSelectedItems is not empty, you can also use it instead of having a self.currentIndexPath property

    // move in the opposite direction for the movement to be intuitive
    // So swiping " <-- " should show index on the right (row + 1)
    if gesture.direction == .left {
        newIndex = IndexPath(row: newIndex.row+1, section: newIndex.section)
    } else {
        newIndex = IndexPath(row: newIndex.row-1, section: self.currentIndexPath!.section)
    }

    if canPresentPageAt(indexPath: newIndex) {
        // Programmatically select the item and make the collectionView scroll to the correct number
        self.collectionview.selectItem(at: newIndex, animated: true, scrollPosition: UICollectionViewScrollPosition.centeredHorizontally)
        // The delegate method is not automatically called when you select programmatically
        self.collectionView(self.collectionview, didSelectItemAt: newIndex!)
    } else {
        // Do something when the landing page is invalid (like if the swipe would got to page at index -1 ...)
        // You could choose to direct the user to the opposite side of the collection view (like the VC at index self.items.count-1
        print("You are tying to navigate to an invalid page")
    }
}

并且由于您是通过编程方式进行滑动，因此在尝试实际移动之前，必须确保滑动 有效 。您必须 添加安全检查 ：

/** You can use an helper method for those checks
 */
func canPresentPageAt(indexPath: IndexPath) -> Bool {
    // Do necessary checks to ensure that the user can indeed go to the desired page
    // Like: check if you have a non-nil ViewController at the given index. (If you haven't implemented index 3,4,5,... it should return false)
    //
    // This method can be called either from a swipe
    // or another way when you need it
    if indexPath.row < 0 || indexPath.row >= self.items.count {
        print("You are trying to go to a non existing page")
        return false
    } else {
        print("If you haven't implemented a VC for page 4 it will crash here")
        return true;
    }
}

最后，您可以在中设置默认的indexPath
self.currentIndexPath，viewDidLoad以便用户在登陆主VC时已经可以滑动而无需在collectionView中选择另一个VC。

注意：如果您在子ViewController中碰巧有手势识别器，则某些手势可能会发生冲突，您将必须学习如何使用诸如的委托方法来解决此类冲突gestureRecognizer(_:shouldRequireFailureOf:)。