The simplest and most brutal way to achieve infinite cyclic scrolling uiscrollview

viewcontroller.swift//uiscrollview_example////Created by xxx on 16/4/1.//copyright©2016 year xxx. All rights Reserved.//import Uikitclass Viewcontroller:uiviewcontroller, uiscrollviewdelegate {var scrollview:ui    scrollview!    var childcacheview:[uiview]! Override Func Viewdidload () {super.viewdidload ()//Do any additional setup after loading the view, typical        Ly from a nib. Setupview ()} override func didreceivememorywarning () {super.didreceivememorywarning ()//Dispose of    Any resources the can be recreated. } func Setupview () {Childcacheview = [] Let frame = CGRectMake (0, 0, Self.view.frame . Size.width, +) Let ScrollView = Uiscrollview (frame:frame) scrollview.delegate = self Self.view.ad Dsubview (scrollView) Self.scrollview = scrollView var offset_x:cgfloat = 0.0 Let ind Exs = [TotalCount-1, 0, 1] for I in 0.. < 3 {Let Childview = CreateChildView (indexs[i]) Childview.frame = CGRectMake (0.0 + offset_x, 0, self . View.frame.size.width, Scrollview.addsubview (childview) offset_x + = CGFloat (self.view.frame.si                Ze.width) Childview.tag = Indexs[i] Childcacheview.append (Childview)}        Scrollview.contentsize = Cgsizemake (self.view.frame.size.width * 3.0, +) scrollview.pagingenabled = True                Scrollview.showsverticalscrollindicator = False Scrollview.showshorizontalscrollindicator = False Scrollview.setcontentoffset (cgpointmake (width, 0), animated:false) Let left = UIButton (frame:cgrectmake        (0, 410, 100, 40)) Left.settitle ("left", ForState:UIControlState.Normal) Left.settitlecolor (Uicolor.blackcolor (), Forstate:uicontrol State.normal) Left.addgesturerecognizer (UITapGestureRecognizer (target:self, Action: #selector (Viewcontroller.tapLeftButton (_:))) Self.view.addSubview (left) Let right = UIButton (Frame:cgrectmake (200, 410, 100, 4 0)) Right.settitle ("right", ForState:UIControlState.Normal) Right.settitlecolor (Uicolor.blackcolor (), forSt Ate:UIControlState.Normal) Right.addgesturerecognizer (UITapGestureRecognizer (target:self, Action: #selector (VIEWC        Ontroller.taprightbutton (_:)))) Self.view.addSubview (right)} var width:cgfloat {        Return Self.view.frame.size.width} func Prevchildview (), UIView {return childcacheview[0]}        Func Currchildview (), UIView {return childcacheview[1]} func Nextchildview () UIView { return childcacheview[2]} var totalcount = 8 var currentindex:int = 0 var urls = ["http ://pic3.zhongsou.com/image/3807f47d76cc2876255.jpg "," http://d.hiphotos.baidu.com/zhidao/pic/item/ 902397dda144ad3452a5d2fad2a20cf431ad85b0.JPG "," http://photo.niaolei.org.cn/uploads/201212/1356349545RuOuHkAy.jpg "," http://img3.fengniao.com/forum/a Ttachpics/155/160/6191982.jpg "," http://img0.pconline.com.cn/pconline/1403/03/4374256_05_thumb.jpg "," http:/ /photo.niaolei.org.cn/uploads/201212/1356350324tg2ii27r.jpg "," http://images3.qianyan.biz/qy/1/20/89/  201472417401165442030.jpg "," http://pic3.zhongsou.com/image/380bccf5f1d656ba95e.jpg "] @objc private func Tapimage (Gesture:uigesturerecognizer) {print ("Tapimage ...")} @objc private Func Tapleftbutton (gesture : Uigesturerecognizer) {print ("Tapleftbutton ...") var offset = Scrollview.contentoffset Offs Et.x-= width scrollview.setcontentoffset (offset, animated:true)} @objc private func Taprightbutton (GES        Ture:uigesturerecognizer) {print ("Taprightbutton ...") var offset = Scrollview.contentoffset Offset.x + = width scrollview.sEtcontentoffset (offset, animated:true)} func scrollviewdidscroll (Scrollview:uiscrollview) {print ("SCR         Ollviewdidscroll...\ (Scrollview.contentoffset)}} func scrollviewdidenddecelerating (Scrollview:uiscrollview) {        Print ("scrollviewdidenddecelerating...\ (Scrollview.contentoffset)") Computescrolloffset ()} Func scrollviewwillbegindragging (Scrollview:uiscrollview) {print ("scrollviewwillbegindragging...\ (scrollView.c Ontentoffset)} func scrollviewwillbegindecelerating (Scrollview:uiscrollview) {print ("scrollviewwillb Egindecelerating...\ (Scrollview.contentoffset)}} func Scrollviewdidendscrollinganimation (scrollview:uiscrollv        Iew) {print ("scrollviewdidendscrollinganimation...\ (Scrollview.contentoffset)") Computescrolloffset ()}        Func Computescrolloffset () {Let offset_x = scrollview.contentoffset.x Let index = Offset_x/width     If index = = 0 {       Swipe forward print ("swipe forward") Let Currview = Currchildview () Let NextView = NE            Xtchildview () Let PrevView = Prevchildview () Currchildview (). frame.origin.x + = width                        Prevchildview (). frame.origin.x + = width nextchildview (). frame.origin.x-= width * 2.0 Scrollview.setcontentoffset (cgpointmake (width, 0), animated:false) childcacheview[0] = Nextv Iew childcacheview[1] = prevview childcacheview[2] = Currview Updatechildview (Childcacheview[0], Currindex:childcacheview[1].tag, Increaseindex:false)}            else If index = = 2 {//Slide back print ("swipe backwards") Let Currview = Currchildview () Let NextView = Nextchildview () Let PrevView = Prevchildview () currchildview (). fr ame.origin.x-= width Nextchildview ().frame.origin.x-= width Prevchildview (). frame.origin.x + = width * 2.0 Scrollview.setcont Entoffset (cgpointmake (width, 0), animated:false) childcacheview[0] = Currview Childcach EVIEW[1] = NextView childcacheview[2] = PrevView Updatechildview (childcacheview[2], Curr        Index:childcacheview[1].tag, Increaseindex:true)}} func CreateChildView (index:int), UIView { Let ImageView = Uiimageview () imageview.userinteractionenabled = True Imageview.addgesturerecognizer (UITAPG Esturerecognizer (Target:self, Action: #selector (Viewcontroller.tapimage (_:)))) Let label = UILabel (frame: CGRectMake (0, 0, +)) Label.text = "Label:\ (index)" Label.tag = Label.font = uifont.systemf Ontofsize (28.0) Label.textcolor = Uicolor.whitecolor () imageview.addsubview (label) ImageView. Kf_setimagewithurl (Nsurl(String:urls[index])!, Placeholderimage:uiimage (named: "Test")) return ImageView} func Updatec Hildview (Childview:uiview, Currindex:int, Increaseindex:bool) {var index = 0 Let label = CHILDVIEW.VIEWW Ithtag (as!)                UILabel if Increaseindex {index = currindex + 1 If index > totalCount-1 { index = 0}} else {index = currIndex-1 If index < 0 {Inde x = totalCount-1}} label.text = "label:\ (index)" Childview.tag = Index (childvi EW as! Uiimageview). Kf_setimagewithurl (Nsurl (String:urls[index])!, Placeholderimage:uiimage (named: "Test")}}

Create a blank project and paste the code directly into a copy.

The picture download uses Onecat's kingfisher, downloads itself.

Note Configure Info.plist, add

<key>NSAppTransportSecurity</key><dict>    <key>NSAllowsArbitraryLoads</key>    <true/></dict>

Over

The simplest and most brutal way to achieve infinite cyclic scrolling uiscrollview