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UICollectionview代理方法的执行顺序：
//手指在屏幕上开始拖拽
func scrollViewWillBeginDragging(_ scrollView: UIScrollView)
//停止拖拽，手指离开了屏幕，
func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool)
//手动拖拽，手指离开了屏幕，滚动的cell停止加速度,减速完成(滚动停止)
func scrollViewDidEndDecelerating(_ scrollView: UIScrollView)
//停止滚动,自动滚动才执行，手势拖拽后停下来，这个方法不会执行
func scrollViewDidEndScrollingAnimation(_ scrollView: UIScrollView)
1.*************cell多选***********
包括：全部选中、全部取消、单个选中、单个取消
参考：
重点：allowsMultipleSelection = true
collec.indexPathsForSelectedItems保存着被选中item的indexPath；
/** cell多选，https://blog.csdn.net/qq_22157341/article/details/79184479 全部选中、全部取消、单个选中、单个取消 */import UIKitclass LYBMutipleSelectCellCollectionview: UIView ,UICollectionViewDelegate,UICollectionViewDataSource{ var collec:UICollectionView? var indexpathArr:[IndexPath]=[]//选中的cell的indexpath数组 override init(frame: CGRect) { super.init(frame: frame) createCollectionView() } required init?(coder aDecoder: NSCoder) { fatalError("init(coder:) has not been implemented") } lazy var sureAndCancelView:UIView={ let v:UIView=UIView.init(frame: CGRect.init(x: 0, y: 0, width: Int(WIDTH), height: 50)) let cancelBtn:UIButton=UIButton.init(frame: CGRect.init(x: 20, y: 0, width: 100, height: 50)) cancelBtn.setTitle("取消", for: UIControl.State.normal) cancelBtn.addTarget(self, action: #selector(cancelClick), for: UIControl.Event.touchUpInside) cancelBtn.setTitleColor(UIColor.black, for: UIControl.State.normal) v.addSubview(cancelBtn) let sureBtn:UIButton=UIButton.init(frame: CGRect.init(x:WIDTH-120, y: 0, width: 100, height: 50)) sureBtn.setTitle("全选", for: UIControl.State.normal) sureBtn.addTarget(self, action: #selector(sureClick), for: UIControl.Event.touchUpInside) sureBtn.setTitleColor(UIColor.black, for: UIControl.State.normal) v.addSubview(sureBtn) return v }() //确定按钮 @objc func sureClick(sender:UIButton){ print("确定") selectAllcell(isselectOrcancel: true) } //取消按钮 @objc func cancelClick(sender:UIButton){ print("取消") selectAllcell(isselectOrcancel: false) } func createCollectionView(){ addSubview(sureAndCancelView) let flowLayout = UICollectionViewFlowLayout.init() flowLayout.itemSize=CGSize.init(width: WIDTH/4, height: WIDTH/4) flowLayout.minimumLineSpacing=0 flowLayout.minimumInteritemSpacing=0// flowLayout.headerReferenceSize = CGSize.init(width: WIDTH, height: 50)//组头的高度 collec = UICollectionView.init(frame: CGRect.init(x: 0, y: 50, width: Int(WIDTH), height: Int(HEIGHT)-Int(bottomSafeHeight)-Int(TopSpaceHigh)-50), collectionViewLayout: flowLayout) collec?.backgroundColor=UIColor.white collec?.delegate=self collec?.dataSource=self collec?.register(LYBMutipleselectcel.classForCoder(), forCellWithReuseIdentifier: "LYBMutipleselectcel") collec?.allowsMultipleSelection=true addSubview(collec!) } func numberOfSections(in collectionView: UICollectionView) -> Int { return 1 } func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int { return 12 } func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell { let cell:LYBMutipleselectcel = collectionView.dequeueReusableCell(withReuseIdentifier: "LYBMutipleselectcel", for: indexPath) as! LYBMutipleselectcel cell.backgroundColor=UIColor.red return cell } func collectionView(_ collectionView: UICollectionView, shouldSelectItemAt indexPath: IndexPath) -> Bool { return true } //选中cell，第一次点击是选中 func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) { selectorcancel(collectionview: collectionView) } //选中cell后设置cell页面的内容状态 func selectorcancel(collectionview:UICollectionView){ //选中 indexpathArr=(collec?.indexPathsForSelectedItems)!//所有被选中的cell的indexpath for indexpah in indexpathArr{ let cell:LYBMutipleselectcel=collec!.cellForItem(at: indexpah) as! LYBMutipleselectcel cell.isSelect=true//重写cell的属性 cell.isSelected=true } print("选中\(indexpathArr)") } //取消选中cell，第二次点击是取消 func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) { indexpathArr=(collec?.indexPathsForSelectedItems)!//所有被选中的cell的indexpath let cell:LYBMutipleselectcel=collec!.cellForItem(at: indexPath) as! LYBMutipleselectcel cell.isSelect=false//重写cell的属性 cell.isSelected=false print("取消\(indexpathArr)") } //cell全部选中或取消 func selectAllcell(isselectOrcancel:Bool){ indexpathArr=(collec?.indexPathsForVisibleItems)!//所有可见cell的indexpath for indexpah in indexpathArr { let cell:LYBMutipleselectcel=collec!.cellForItem(at: indexpah) as! LYBMutipleselectcel if isselectOrcancel{ collec?.selectItem(at: indexpah, animated: true, scrollPosition: UICollectionView.ScrollPosition.bottom)//设为选中状态 cell.isSelect=true//重写cell的属性 cell.isSelected=true indexpathArr=(collec?.indexPathsForSelectedItems)!//所有被选中的cell的indexpath }else { collec?.deselectItem(at: indexpah, animated: true)//取消选中的状态 cell.isSelect=false//重写cell的属性 cell.isSelected=false indexpathArr=(collec?.indexPathsForSelectedItems)!//所有被选中的cell的indexpath } } print("全选或取消\(String(describing: indexpathArr))") } }*************/** 多选cell */import UIKitclass LYBMutipleselectcel: UICollectionViewCell { var imageV:UIImageView!var img:UIImage=UIImage.init(named: "center")!{ willSet(newimage) { imageV.image= newimage //或者在didSet中使用imageV.image= img } didSet(oldvalue) { imageV.image= image//这里的img已经是新的值了 } } //是否选中 var isSelect:Bool=false{ didSet{ print("\(isSelect)") if isSelect{ selectbtn.setImage(UIImage.init(named: "comm_btn_checkmark"), for: UIControl.State.normal) }else { selectbtn.setImage(UIImage.init(), for: UIControl.State.normal) } } } override init(frame: CGRect) { super.init(frame: frame) createCell() } required init?(coder aDecoder: NSCoder) { fatalError("init(coder:) has not been implemented") } func createCell(){ imageV = UIImageView.init(frame:CGRect.init(x: 0, y: 0, width: self.frame.size.width, height: self.frame.size.height)) imageV.image=UIImage.init(named: "appstart") addSubview(imageV) addSubview(selectbtn) } lazy var selectbtn:UIButton={ let btn:UIButton=UIButton.init(frame: CGRect.init(x: 0, y: self.frame.size.width-50, width: 30, height: 30)) return btn }()}
2.***********普通的collectionview使用*********
/*** 普通的collectionview */import UIKitclass LYBNormalcollectionview: UIView ,UICollectionViewDelegate,UICollectionViewDataSource { var collec:UICollectionView? override init(frame: CGRect) { super.init(frame: frame) createCollectionView() } required init?(coder aDecoder: NSCoder) { fatalError("init(coder:) has not been implemented") } func createCollectionView(){ let flowLayout = UICollectionViewFlowLayout.init() flowLayout.itemSize=CGSize.init(width: 100, height: 100) flowLayout.headerReferenceSize = CGSize.init(width: WIDTH, height: 50)//组头的高度 collec = UICollectionView.init(frame: CGRect.init(x: 0, y: 0, width: Int(WIDTH), height: Int(HEIGHT)-Int(bottomSafeHeight)-Int(TopSpaceHigh)), collectionViewLayout: flowLayout) collec?.backgroundColor=UIColor.white collec?.delegate=self collec?.dataSource=self collec?.register(LYBNOrmalCollectionviewcell.classForCoder(), forCellWithReuseIdentifier: "LYBNOrmalCollectionviewcell") //注册组头 collec!.register(LYBCollectionviewHeader.classForCoder(), forSupplementaryViewOfKind: UICollectionView.elementKindSectionHeader, withReuseIdentifier: "homeCollectionviewHeader") addSubview(collec!) } func numberOfSections(in collectionView: UICollectionView) -> Int { return 1 } func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int { return 5 } func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell { let cell:LYBNOrmalCollectionviewcell = collectionView.dequeueReusableCell(withReuseIdentifier: "LYBNOrmalCollectionviewcell", for: indexPath) as! LYBNOrmalCollectionviewcell cell.backgroundColor=UIColor.red return cell } //UICollectionElementKindSectionHeader和 kind 比较来区分header 和footer func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView { var headerView : LYBCollectionviewHeader = (collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "homeCollectionviewHeader", for: indexPath as IndexPath) as? LYBCollectionviewHeader)! //分区头 if kind == UICollectionView.elementKindSectionHeader{ headerView = (collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "homeCollectionviewHeader", for: indexPath as IndexPath) as? LYBCollectionviewHeader)! } //分区尾 else if kind == UICollectionView.elementKindSectionFooter{ } return headerView } }****************/** collectionviewcell */import UIKitclass LYBNOrmalCollectionviewcell: UICollectionViewCell { var imageV:UIImageView! var image:String="appstart"{ willSet(image) { } didSet { imageV.image=UIImage.init(named: image) } } override init(frame: CGRect) { super.init(frame: frame) createCell() } required init?(coder aDecoder: NSCoder) { fatalError("init(coder:) has not been implemented") } func createCell(){ imageV = UIImageView.init(frame:CGRect.init(x: 0, y: 0, width: self.frame.size.width, height: self.frame.size.height)) imageV.image=UIImage.init(named: "appstart") addSubview(imageV) }}**********/*** colllectionview组头 */import UIKitclass LYBCollectionviewHeader: UICollectionReusableView { override init(frame: CGRect) { super.init(frame: frame) initViews() } func initViews(){ backgroundColor=UIColor.blue addSubview(lab) } required init?(coder aDecoder: NSCoder) {fatalError("init(coder:) has not been implemented") }lazy var lab:UILabel={ let lbl=UILabel.init(frame: CGRect.init(x: 0, y: 0, width: WIDTH, height: self.frame.size.height))lbl.text="便民" return lbl}()}
******************************
//组头
import UIKit
class LYBHomeconvienceCollectionHeaderViewCollectionReusableView: UICollectionReusableView {
override init(frame: CGRect) {
super.init(frame: frame)
initViews()
}
func initViews(){
backgroundColor=UIColor.blue
addSubview(lab)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
lazy var lab:UILabel={
let lbl=UILabel.init(frame: CGRect.init(x: 0, y: 0, width: WIDTH, height: self.frame.size.height))
lbl.text="便民"
return lbl
}()
}
*****************设置cell
//便民板块的cell
import UIKit
class LYBHomeConvienceCollectionViewCell: UICollectionViewCell {
override init(frame: CGRect) {
super.init(frame: frame)
initViews()
}
func initViews(){
addSubview(imageV)
addSubview(lab)
lab.backgroundColor=UIColor.white
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func setcell(imageStr:String,titleStr:String) {
imageV.image=UIImage.init(named: imageStr)
lab.text=titleStr
}
lazy var imageV:UIImageView={
let imagev=UIImageView.init(frame: CGRect.init(x: 20, y: 20, width: WIDTH/4-40, height: WIDTH/4-40))
return imagev
}()
lazy var lab:UILabel={
let lbl=UILabel.init(frame: CGRect.init(x: 0, y: WIDTH/4, width: WIDTH/4, height: 30))
lbl.textAlignment=NSTextAlignment.center
lbl.font=UIFont.systemFont(ofSize: 13)
return lbl
}()
}
************************主控制器
import UIKit
class LYBConvinienceCollectionView: UIView,UICollectionViewDelegate,UICollectionViewDataSource{
func numberOfSections(in collectionView: UICollectionView) -> Int {
return 1
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return imageArr.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell:LYBHomeConvienceCollectionViewCell=collectionview.dequeueReusableCell(withReuseIdentifier: homeConvienceCollectionIdentifier, for: indexPath) as! LYBHomeConvienceCollectionViewCell
cell.setcell(imageStr: imageArr[indexPath.item], titleStr: titleArr[indexPath.item])
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
collectionview .deselectItem(at: indexPath, animated: true)
}
//UICollectionElementKindSectionHeader和 kind 比较来区分header 和footer
func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
var headerView : LYBHomeconvienceCollectionHeaderViewCollectionReusableView = (collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "homeCollectionviewHeader", for: indexPath as IndexPath) as? LYBHomeconvienceCollectionHeaderViewCollectionReusableView)!
//分区头
if kind == UICollectionElementKindSectionHeader{
headerView = (collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "homeCollectionviewHeader", for: indexPath as IndexPath) as? LYBHomeconvienceCollectionHeaderViewCollectionReusableView)!
}
//分区尾
else if kind == UICollectionElementKindSectionFooter{
}
return headerView
}
***********//组头的高度---这个方法不执行；换成flow.headerReferenceSize = CGSize.init(width: WIDTH, height: 50)就可以了
func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize{
return CGSize.init(width: WIDTH, height: 50)
}
注意：设置组头的注意事项：
1.当前控制器遵守协议(UICollectionViewDelegateFlowLayout);
2.注意设置头部的size;3. 当设置size,依然无法显示的原因:-> 不要使用代理方法,(- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section);->换成使用直接赋值方法(flowLayout.headerReferenceSize = CGSizeMake(xx, xx);).4.未显示的原因:代理方法是最后才执行的.所以当内部添加了header之后,还没有走代理方法执行size,因此不会显示.***************
override init(frame: CGRect) {
super.init(frame: frame)
initViews()
}
func initViews(){
flow.itemSize=CGSize.init(width: WIDTH/4, height: WIDTH/4+30)
flow.minimumLineSpacing=0
flow.minimumInteritemSpacing=0
addSubview(collectionview)
collectionview.delegate=self
collectionview.dataSource=self
collectionview.backgroundColor=UIColor.white
*******flow.headerReferenceSize = CGSize.init(width: WIDTH, height: 50)//设置组头高度
//注册cell
collectionview .register(LYBHomeConvienceCollectionViewCell.classForCoder(), forCellWithReuseIdentifier: homeConvienceCollectionIdentifier)
//注册组头
collectionview.register(LYBHomeconvienceCollectionHeaderViewCollectionReusableView.classForCoder(), forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: "homeCollectionviewHeader")
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
lazy var imageArr:[String] = {
let imageAr=["lczq","banCredit","homeDaikuan","wfsc","sjcz","flowcz","mediaIcon","jtfk"]
return imageAr
}()
lazy var titleArr:[String] = {
let titleAr=["信用卡垫还","大额信用卡","贷款","商城","话费","流量","共享媒体","违章查询"]
return titleAr
}()
lazy var flow:UICollectionViewFlowLayout = {
let flo=UICollectionViewFlowLayout.init()
return flo
}()
lazy var collectionview:UICollectionView = {
let collect=UICollectionView.init(frame: CGRect.init(x: 0, y: 0, width: WIDTH, height: (WIDTH/4+30)*2+50), collectionViewLayout: flow)
return collect
}()
}