Swift下使用UICollectionView 实现长按拖拽功能

简单用Swift写了一个collectionview的拖拽点击排序效果;

拖拽排序是新闻类的App可以说是必有的交互设计，如今日头条，网易新闻等。

GitHub地址：https://github.com/wangliujiayou/Swift-dragLabel 欢迎Star.

效果

主要代码

手势长按移动

1.给CollectionViewCell添加一个长按手势.

private lazy var collectionView: UICollectionView = {
let clv = UICollectionView(frame: self.view.frame, collectionViewLayout: ChannelViewLayout())
clv.backgroundColor = UIColor.white
clv.delegate = self
clv.dataSource = self
clv.register(ChannelViewCell.self, forCellWithReuseIdentifier: ChannelViewCellIdentifier)
clv.register(ChannelHeaderView.self, forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: ChannelViewHeaderIdentifier)
let longPress = UILongPressGestureRecognizer(target: self, action: #selector(longPressGesture(_:)))
clv.addGestureRecognizer(longPress)
return clv
}()

2.开始长按时对cell进行截图或拷贝一个cell，并隐藏cell.

//MARK: - 长按开始
private func dragBegan(point: CGPoint) {
indexPath = collectionView.indexPathForItem(at: point)
if indexPath == nil || (indexPath?.section)! > 0 || indexPath?.item == 0
{return}
let item = collectionView.cellForItem(at: indexPath!) as? ChannelViewCell
item?.isHidden = true
dragingItem.isHidden = false
dragingItem.frame = (item?.frame)!
dragingItem.text = item!.text
//放大效果(此处可以根据需求随意修改)
dragingItem.transform = CGAffineTransform(scaleX: 1.1, y: 1.1)
}

3.在手势移动的时候，找到目标是的indexPatch，再调用系统的api交换这个cell和隐藏cell的位置，并且更新数据.

//MARK: - 移动过程
private func drageChanged(point: CGPoint) {
if indexPath == nil || (indexPath?.section)! > 0 || indexPath?.item == 0 {return}
dragingItem.center = point
targetIndexPath = collectionView.indexPathForItem(at: point)
if targetIndexPath == nil || (targetIndexPath?.section)! > 0 || indexPath == targetIndexPath || targetIndexPath?.item == 0 {return}
// 更新数据
let obj = selectedArr[indexPath!.item]
selectedArr.remove(at: indexPath!.row)
selectedArr.insert(obj, at: targetIndexPath!.item)
//交换位置collectionView.moveItem(at: indexPath!, to: targetIndexPath!)
//进行记录
indexPath = targetIndexPath
}

4.手势停止或取消时，移除view，显示隐藏cell. (这里手势取消也要掉用此方法)

//MARK: - 长按结束或取消
private func drageEnded(point: CGPoint) {
if indexPath == nil || (indexPath?.section)! > 0 || indexPath?.item == 0 {return}
let endCell = collectionView.cellForItem(at: indexPath!)
UIView.animate(withDuration: 0.25, animations: {
self.dragingItem.transform = CGAffineTransform.identity
self.dragingItem.center = (endCell?.center)!
}, completion: {
(finish) -> () in
endCell?.isHidden = false
self.dragingItem.isHidden = true
self.indexPath = nil
})
}

点击移动

collectionView的点击方法,我这里分为两段,第一段为点击处理事件,第二段为点击添加添加标签(编辑状态下第一段可以点击排序)

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
if indexPath.section > 0 {
// 更新数据
let obj = recommendArr[indexPath.item]
recommendArr.remove(at: indexPath.item)
selectedArr.append(obj)
//移动方法
collectionView.moveItem(at: indexPath, to: NSIndexPath(item: selectedArr.count - 1, section: 0) as IndexPath)
} else {
if isEdite {
if indexPath.item == 0 {return}
// 更新数据
let obj = selectedArr[indexPath.item]
selectedArr.remove(at: indexPath.item)
recommendArr.insert(obj, at: 0)
//移动方法collectionView.moveItem(at: indexPath, to: NSIndexPath(item: 0, section: 1) as IndexPath)
} else {
if switchoverCallback != nil {
//处理点击的闭包
switchoverCallback!(selectedArr, recommendArr, indexPath.item)
_ = navigationController?.popViewController(animated: true)
}
}
}
}

其他

此代码只是一个效果,没有怎么封装,如果仔细看过的朋友可以知道其实没有多么复杂

点击移动

collectionView.moveItem(at: indexPath, to: NSIndexPath(item: 0, section: 1) as IndexPath)

拖拽移动

collectionView.moveItem(at: indexPath!, to: targetIndexPath!)

主要就是这两个方法,其他都是处理逻辑以及视图效果.

提示

如果你们是从iOS9开始适配的话，那么可以用系统的Api，非常简单好用,大家这里可以自己去试试.

// Support for reordering
@available(iOS 9.0, *)
open func beginInteractiveMovementForItem(at indexPath: IndexPath) -> Bool // returns NO if reordering was prevented from beginning - otherwise YES
@available(iOS 9.0, *)
open func updateInteractiveMovementTargetPosition(_ targetPosition: CGPoint)
@available(iOS 9.0, *)
open func endInteractiveMovement()
@available(iOS 9.0, *)
open func cancelInteractiveMovement()

源码可以从这里下载

以上所述是小编给大家介绍的Swift下使用UICollectionView 实现长按拖拽功能，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对脚本之家网站的支持！

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