当我将其添加到我的 UICollectionViewController
子类时,在 iOS9 中可以重新排序
override func collectionView(collectionView: UICollectionView,
moveItemAtIndexPath sourceIndexPath: NSIndexPath,
toIndexPath destinationIndexPath: NSIndexPath)
当此 UICollectionViewController
子类嵌入到容器 View 中时,它不起作用。
我已经对问题进行了演示 here
关于为什么或如何解决它的任何想法?
最佳答案
Scooter 的答案是正确的! 这是 Swift 3 语法版本:
import UIKit
class ViewController: UIViewController
{
// MARK: - IBOutlets
@IBOutlet weak var uiCollectionView: UICollectionView!
// MARK: - Lifecycle
override func viewDidLoad()
{
super.viewDidLoad()
let longPressGesture = UILongPressGestureRecognizer(target: self, action: #selector(ViewController.handleLongGesture))
self.uiCollectionView.addGestureRecognizer(longPressGesture)
}
// MARK: - Gesture recogniser
@objc func handleLongGesture(gesture: UILongPressGestureRecognizer)
{
switch(gesture.state)
{
case .began:
guard let selectedIndexPath = self.uiCollectionView.indexPathForItem(at: gesture.location(in: self.uiCollectionView)) else
{
break
}
self.uiCollectionView.beginInteractiveMovementForItem(at: selectedIndexPath)
case .changed:
self.uiCollectionView.updateInteractiveMovementTargetPosition(gesture.location(in: gesture.view!))
case .ended:
self.uiCollectionView.endInteractiveMovement()
default:
self.uiCollectionView.cancelInteractiveMovement()
}
}
}
// MARK: - UICollectionViewDataSource
extension ViewController: UICollectionViewDataSource
{
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int
{
// TODO: Link to your data model
return 20
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell
{
// TODO: Link to your data model
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "MyCell", for: indexPath)
return cell
}
func collectionView(_ collectionView: UICollectionView,
moveItemAt sourceIndexPath: IndexPath,
to destinationIndexPath: IndexPath)
{
// TODO: Update your data model to reflect the change
}
}
// MARK: - UICollectionViewDelegate
extension ViewController: UICollectionViewDelegate
{
// TODO: Add any UICollectionViewDelegate here if needed.
}
请注意,此代码不考虑触摸位置偏移 - 因此当您开始拖动时,您的单元格将“跳”到手指下方的中心。如果你想阻止这种情况,那么你需要在你的 UIViewController
中定义一个 CGPoint
属性(在下面的代码中命名为 initialGestureLocationInCell
)。然后用这个替换初始示例:
[...]
case .began:
guard let selectedIndexPath = self.uiCollectionView.indexPathForItem(at: gesture.location(in: self.uiCollectionView)) else
{
break
}
let selectedCell = self.uiCollectionView.cellForItem(at: selectedIndexPath)!
let gestureLocationInCell_RelativeToOrigin = gesture.location(in: selectedCell)
let gestureLocationInCell_RelativeToCentre = CGPoint(x: gestureLocationInCell_RelativeToOrigin.x - selectedCell.frame.size.width/2,
y: gestureLocationInCell_RelativeToOrigin.y - selectedCell.frame.size.height/2)
self.initialGestureLocationInCell = gestureLocationInCell_RelativeToCentre
self.uiCollectionView.beginInteractiveMovementForItem(at: selectedIndexPath)
case .changed:
let gestureLocationInCollectionView = gesture.location(in: gesture.view!)
let targetPosition = CGPoint(x: gestureLocationInCollectionView.x - self.initialGestureLocationInCell.x,
y: gestureLocationInCollectionView.y - self.initialGestureLocationInCell.y)
self.uiCollectionView.updateInteractiveMovementTargetPosition(targetPosition)
[...]
关于ios - 嵌入容器 View 时,UICollectionViewController 重新排序不起作用,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/35166607/