Swift下使用UICollectionView 实现长按拖拽功能

时间:2021-10-07 04:59:51

导读

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

Swift下使用UICollectionView 实现长按拖拽功能

主要代码

手势长按移动

1.给CollectionViewCell添加一个长按手势.

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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.

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//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.

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//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)

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//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)

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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

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

拖拽移动

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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.

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// 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服务器之家网站的支持!

原文链接:http://www.jianshu.com/p/39ef303680fe