在 CollectionView 中的单元格之间拖放不起作用，iOS、PanGestureRecognizer 和 Swift3

Question

我尝试创建具有 2 行和 2 列的集合视图，并在单元格之间进行简单的拖放操作。我会 post 我的控制器的 collectionView() 和 panGestureAction() 是什么样子的。当我将手势识别器添加到故事中时，我将其放在可重复使用的单元格上。

问题是当我尝试拖放时，只有最后一个单元格可以引发事件，并且我看到了控制台日志（"began" 和 "ended"）。如果我注释行 cell.contentView.addGestureRecognizer(recognizer)，只有第一个单元格会引发事件。

我该怎么办，我的所有单元格都在记录消息（能够识别拖放）？

@IBOutlet weak var recognizer: UIPanGestureRecognizer!

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

    guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellReusable, for: indexPath) as? CellCollectionViewCell else {
        fatalError("The dequeued cell is not an instance of CellCollectionViewCell.")
    }

    cell.contentView.addGestureRecognizer(recognizer)

    // Configure the cell
    cell.valueLabel?.text = String(100);
    cell.layer.borderWidth = 5.0
    cell.layer.borderColor = UIColor.red.cgColor

    cells.append(cell);

    return cells[cells.count-1];
}


 @IBAction func panGestureAction(_ sender: UIPanGestureRecognizer) {
    if recognizer.state == UIGestureRecognizerState.began {
        print("began");
    }

    if recognizer.state == UIGestureRecognizerState.ended {
        print("ended");
    }
}

更新：

import UIKit

class GridControllerCollectionViewController: UICollectionViewController, UIGestureRecognizerDelegate {

private let cellReusable = "CellCollectionViewCell"

fileprivate let numberOfColumns = 2
fileprivate let numberOfRows = 4
fileprivate var gesture: UILongPressGestureRecognizer?

@IBOutlet var collectionViewOutlet: UICollectionView!

fileprivate var cells = [CellCollectionViewCell]()

override func viewDidLoad() {
    super.viewDidLoad()

    gesture = UILongPressGestureRecognizer(target: self, action: #selector(panGestureAction(_:)))
    gesture?.minimumPressDuration = 0.5
    gesture?.delegate = self

    //have tried with first line, second, and with both
    collectionViewOutlet.addGestureRecognizer(gesture!)
    collectionView?.addGestureRecognizer(gesture!)

    print("gesture delegate is assigned!")
}

override func numberOfSections(in collectionView: UICollectionView) -> Int {
    return numberOfRows
}


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

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

    guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellReusable, for: indexPath) as? CellCollectionViewCell else {
        fatalError("The dequeued cell is not an instance of CellCollectionViewCell.")
    }

    // Configure the cell
    cell.valueLabel?.text = String(100);
    cell.layer.borderWidth = 5.0
    cell.layer.borderColor = UIColor.red.cgColor

    cells.append(cell);

    return cells[cells.count-1];
}

func panGestureAction(_ sender: UILongPressGestureRecognizer) {

    print("panGestureAction was reached!");

//        if gesture?.state == UIGestureRecognizerState.began {
//            print("began");
//        }
//        
//        if gesture?.state == UIGestureRecognizerState.ended {
//            print("ended");
//        }

    switch sender.state {
    case .began:
        print("began")
    case .changed:
        print("changed")
    case .ended:
        print("ended")
    default:
        collectionView?.cancelInteractiveMovement()
    }
}

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
    return true
}

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive press: UIPress) -> Bool {
    return true
}

override func collectionView(_ collectionView: UICollectionView, canMoveItemAt indexPath: IndexPath) -> Bool {
    return true
}
}

Answer 1

不要将手势添加到单元格。它必须添加到您的 collectionView

gesture = UILongPressGestureRecognizer(target: self, action: #selector(panGestureAction(_:)))
gesture.minimumPressDuration = 0.5
gesture.delegate = self
collectionView.addGestureRecognizer(gesture)

实现手势委托方法

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
    return true
}

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive press: UIPress) -> Bool {
    return true
}

重要：实现集合视图数据源方法

func collectionView(_ collectionView: UICollectionView, moveItemAt sourceIndexPath: IndexPath, to destinationIndexPath: IndexPath) {
    //
}

最后，实现您的平移手势动作

func panGestureAction(_ sender: UILongPressGestureRecognizer) {
    switch sender.state {
    case .began:
        guard let indexPath = collectionView.indexPathForItem(at: sender.location(in: collectionView)) else {
            return
        }
        collectionView.beginInteractiveMovementForItem(at: indexPath)        
    case .changed:
        collectionView.updateInteractiveMovementTargetPosition(sender.location(in: collectionView))
    case .ended:
        collectionView.endInteractiveMovement()
    default:
        collectionView.cancelInteractiveMovement()
    }
}

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