之前写过oc版本的筛选界面。最近开发一直在使用swift。再写一个swift版本的筛选。
 先上效果图：

图一 效果图二

我们要的效果是，点击第一组，根据内容联动第三组。

第一组，第二组为单选。第三组为多选

好了，简单说一下思路：

首先创建collectionView。再添加collectionView的头部试图和尾部试图。最后开始写筛选逻辑。

上代码：

private lazy var collection: UICollectionView = {
        let layout = UICollectionViewFlowLayout.init()
        layout.minimumLineSpacing = 12
        layout.sectionInset = UIEdgeInsets(top: 12, left: 16, bottom: 1, right: 15)
        let collection = UICollectionView.init(frame: CGRect.init(x: SCREEN_WIDTH - CGFloat(collectionWidth), y: 0, width: CGFloat(collectionWidth), height: SCREENH_HEIGHT), collectionViewLayout: layout)
        collection.backgroundColor = .white
        collection.delegate = self
        collection.dataSource = self
        collection.alwaysBounceVertical = true
        collection.showsVerticalScrollIndicator = true
        collection.register(YXScreenCell.self, forCellWithReuseIdentifier: "SwiftCollectionViewCell")
        collection.register(UICollectionReusableView.self, forSupplementaryViewOfKind: UICollectionView.elementKindSectionFooter, withReuseIdentifier: "SwiftFooterCollectionReusableView")
        collection.register(UICollectionReusableView.self, forSupplementaryViewOfKind: UICollectionView.elementKindSectionHeader, withReuseIdentifier: "SwiftHeaderCollectionReusableView")
        return collection
    }()
使用懒加载创建collectionView

这里的代码我直觉使用extension 方式实现代理
extension YXScreenView:UICollectionViewDelegate ,UICollectionViewDataSource, UICollectionViewDelegateFlowLayout{
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        if section == 0 {
            return self.screenClassModelList.count
        }
        if section == 1 {
            return 2
        }
        if section == 2 {
            return self.screenTowClassModelList.count
        }
        return 0

    }
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        return self.list.count
    }
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cellString = "SwiftCollectionViewCell"
        let cell = collection.dequeueReusableCell(withReuseIdentifier: cellString, for: indexPath) as! YXScreenCell
        if list.count > 0 {
            let obj = (list[indexPath.section][indexPath.item] as! YXscreenClassModel)
            if indexPath.section == 0 {
                if scenarioArr.contains(obj) {
                    cell.buleColorCell()
                } else {
                    cell.originalColorCell()
                }
            } else if indexPath.section == 1 {
                if taskTypeArr.contains(obj) {
                    cell.buleColorCell()
                } else {
                    cell.originalColorCell()
                }
            } else if indexPath.section == 2 {
                if contentArr.contains(obj) {
                    cell.buleColorCell()
                } else {
                    cell.originalColorCell()
                }
            }
            cell.classModel = obj
        }
        
        return cell
    }
//设置 区头和区尾
   func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
    var reusabView = UICollectionReusableView.init()
       if kind == UICollectionView.elementKindSectionHeader  {
        let headerView:UICollectionReusableView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "SwiftHeaderCollectionReusableView", for: indexPath)
        for v in headerView.subviews{
            v.removeFromSuperview()
        }
        let heardLab = UILabel.init()
        heardLab.font = .systemFont(ofSize: 14)
        heardLab.textColor = UIColor.color136
        headerView.addSubview(heardLab)
        heardLab.snp_makeConstraints { (make) in
            make.left.equalTo(16)
            make.bottom.equalTo(0)
        }
        let hearTestArr = ["任务场景","任务类型","任务内容"]
        heardLab.text = hearTestArr[indexPath.section]
        reusabView = headerView
       }
       
       else {
        let footerView:UICollectionReusableView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "SwiftFooterCollectionReusableView", for: indexPath)
        for v in footerView.subviews{
            v.removeFromSuperview()
        }
        let screenFoot = YXScreenFootView.init()
        footerView.addSubview(screenFoot)
        screenFoot.snp_makeConstraints { (make) in
            make.left.right.top.bottom.equalTo(footerView)
        }
        screenFoot.delegate = self
        reusabView = footerView
       }
       return reusabView
    }//footView是我单独封装出来的一个view。就是图中的 确定，重置按钮，和选择时间的按钮
     //尾部高度
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForFooterInSection section: Int) -> CGSize {
        if section == 2 {
            return CGSize(width: collectionWidth, height: 155)
        }else{
            return CGSize(width: 0, height: 0)
        }
    }
    //头部高度设置
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
        if section == 0 {
            return CGSize(width: collectionWidth, height: 60)
        }else{
            return CGSize(width: collectionWidth, height: 44)
        }
    }
    //设置两个cell的左右间距
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        return 12
    }

好了，到这里基本的collectionview试图应该差不多出来了。下面开始写核心的筛选逻辑。

//这是第二组 写死的数组模型
    var cellSectionTow: [YXscreenClassModel] = [YXscreenClassModel]()
    //第一组section里的几个数据
    private var screenOneSectionlList = [YXScrennDataModel]()
    //这是第一组下每个taskDetailList里的数组模型
    private var oneList = [[YXscreenClassModel]]()
    //第一组Section数组模型
    private var screenClassModelList = [YXscreenClassModel]()
    //第三组section数组模型
    private var screenTowClassModelList = [YXscreenClassModel]()
    //最终给cell赋值的模型。里面放三组数组模型
    var list :[Array] = [Array<Any>]()
前两组为单选，所以我定义了两个index变量：
var indexPathRow: IndexPath?   第一组的indexPatch
var indexPathTow: IndexPath?   第三组的indexPatch
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
//之前用indexPatch进行记录，但是这样太麻烦了。换个思路
    let cell = collection.cellForItem(at: indexPath) as! YXScreenCell
//通过cell拿到对应的model
    let model = cell.classModel as! YXScreenClassModel
       if indexPath.section == 0 {
          if !scenarioArr.contains(model) {  //说明之前点击过了，这次点击的不是同一个cell
                scenarioArr.removeAllObjects()
                scenarioArr.add(model)
                reloadSection(index: indexPath.item)
                collection.reloadData()
            }
     }
           
            
if indexPath.section == 1 {//和第一组的方法一样
            if !taskTypeArr.contains(model) {
                taskTypeArr.removeAllObjects()
                taskTypeArr.add(model)
                collection.reloadData()
            }
        }
        //多选，这个再次点击相同的是可以取消高亮的。
        if indexPath.section == 2 {
           if contentArr.contains(model) {
                contentArr.remove(model)
            } else {
                contentArr.add(model)
            }
            collection.reloadData()
}

//刷新第三组section
    func reloadSection(index:Int){
        let section3Data: [YXscreenClassModel] = self.oneList[index]
        self.screenTowClassModelList.removeAll()
        for m in section3Data {
            //KNLog(m.name)
            let classModel = YXscreenClassModel.init()
            classModel.name = m.name
            screenTowClassModelList.append(classModel)
        }
        list.removeLast()
        list.insert(screenTowClassModelList, at: 2)
        reloadSectionTowData()
        contentArr.removeAllObjects()
        removeCellArr()
    }
//这个是刷新collectionView的方法。必须要用动画方法。否则试图会上下跳。
func reloadSectionTowData(){
        UIView.performWithoutAnimation {
            let indeS = NSIndexSet.init(index: 2)
            collection.reloadSections(indeS as IndexSet)
        }
    }

#最后cell.classModel 这里模型。用的class方式。
//MARK：筛选
class YXscreenClassModel: HandyJSON {
    required init(){
        
    }
    //名字
    var name: String?
    //添加属性是否高亮
    var isSelect:Bool? = false
    
    var code: String?
    var taskSenceCode:String?
}

写完了，谢谢大家！