UICollectionView 单元格重新排序

Question

我正在尝试重新排序我的 CollectionView 单元格。但似乎无法通过 UILongPressGestureRecognizer。状态从开始 -> 更改 -> 结束。但它不会用到 moveItemAtIndexPath 函数。 这是我的代码：

  func collectionView(collectionView: UICollectionView, moveItemAtIndexPath sourceIndexPath: NSIndexPath,toIndexPath destinationIndexPath: NSIndexPath) {

var temp1 = [self.viewThatIsShown.selectionForView?.pageArray.count]

let temp = temp1.removeAtIndex(sourceIndexPath.item)
temp1.insert(temp, atIndex: destinationIndexPath.item)
}
 func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {

    let layout = self.viewThatIsShown.selectionForView!.rawJSON["pages"].arrayValue[section]["layout"].stringValue

    if layout == "video" || layout == "social-media" {
        return 1
    } else if layout == "pre-list" {
        let dataJSON = self.viewThatIsShown.selectionForView!.rawJSON["pages"].arrayValue[section]["data"]
        return dataJSON["listitems"].arrayValue.count
    }

    let dataSet = self.viewThatIsShown.dataForView!.dataArray[section]

    return min(dataSet.embeddedItemsArray.count, 2)

}
 switch(gesture.state) {

    case UIGestureRecognizerState.Began:
        guard let selectedIndexPath = self.collectionView.indexPathForItemAtPoint(gesture.locationInView(self.collectionView)) else {
            break
        }
        collectionView.beginInteractiveMovementForItemAtIndexPath(selectedIndexPath)
    case UIGestureRecognizerState.Changed:
        collectionView.updateInteractiveMovementTargetPosition(gesture.locationInView(gesture.view!))
    case UIGestureRecognizerState.Ended:
        collectionView.endInteractiveMovement()
    default:
        collectionView.cancelInteractiveMovement()
    }

也没有显示错误。我想我在计算部分中的项目数量时犯了一些错误。但是想不通。 P.S 我的 UICollectionview 中有六个部分，我想将其用于拖放部分。

Answer 1

查看 UILongPressGestureRecognizer 选择器的实现会非常有帮助，因为这是拼图的关键部分。不过，一般来说，您需要观察 .began、.changed、.ended 状态，正如您所提到的，并更新位置。一种方法是打开gesture.state 并执行以下操作：

switch gesture.state {
case .began:
    //Get a reference to the indexPath being pressed
    guard let selectedIndexPath = self.collectionView.indexPathForItem(at: gesture.location(in: self.collectionView)) else { break }
    //Start interactive movement
    self.collectionView.beginInteractiveMovementForItem(at: selectedIndexPath)
case .changed:
    //Update position based on new gesture location
    self.collectionView.updateInteractiveMovementTargetPosition(gesture.location(in: self.collectionView))
case .ended:
    //End interaction with cell. This will cause moveItemAtIndexPath to fire.
    self.collectionView.endInteractiveMovement()
case .default:
    //Just to cover your bases
    self.collectionView.cancelInteractiveMovement()
}