'CollectionView move to next cell automatically swift
I am trying to create horizontal slider like Flipkart. I am using collectionView with Horizontal scrolling and paging. Cell contains imageView. I am succeed in scrolling items horizontally manually, but I want all these items to move automatic and manually both. I am not getting how to scroll items of collectionView automatically. Please guide me to do this.
I have use this code in viewDidAppear:
let visibleIndexPath: NSIndexPath = self.collectionView.indexPathForCell(cell)!
self.collectionView.scrollToItemAtIndexPath(visibleIndexPath,
atScrollPosition: UICollectionViewScrollPosition.CenteredHorizontally, animated: true)
Thanks.
EDIT:
import UIKit
class ViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource {
@IBOutlet var pageControl: UIPageControl!
@IBOutlet var collectionView: UICollectionView!
var begin = false
let image1 = UIImage(named: "Slide 1")
let image2 = UIImage(named: "Slide 2")
let image3 = UIImage(named: "Slide 1")
var images = [UIImage]()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
images = [image1!, image2!, image3!]
startTimer()
}
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
pageControl.numberOfPages = images.count
return images.count
}
var cell : CollectionViewCell1!
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
cell = collectionView.dequeueReusableCellWithReuseIdentifier("CollectionViewCell1", forIndexPath: indexPath) as! CollectionViewCell1
cell.cell_image.image = images[indexPath.row]
return cell
}
/**
Scroll to Next Cell
*/
func scrollToNextCell(){
//get cell size
let cellSize = CGSizeMake(self.view.frame.width, self.view.frame.height);
//get current content Offset of the Collection view
let contentOffset = collectionView.contentOffset;
//scroll to next cell
if begin == true
{
pageControl.currentPage == 0
collectionView.scrollRectToVisible(CGRectZero, animated: true)
begin = false
}
else
{
collectionView.scrollRectToVisible(CGRectMake(contentOffset.x + cellSize.width, contentOffset.y, cellSize.width, cellSize.height), animated: true);
}
}
/**
Invokes Timer to start Automatic Animation with repeat enabled
*/
func startTimer() {
NSTimer.scheduledTimerWithTimeInterval(2.0, target: self, selector: #selector(ViewController.scrollToNextCell), userInfo: nil, repeats: true);
}
func scrollViewDidEndDecelerating(scrollView: UIScrollView) {
// If the scroll animation ended, update the page control to reflect the current page we are on
pageControl.currentPage = Int((collectionView.contentOffset.x / collectionView.contentSize.width) * CGFloat(images.count))
if collectionView.contentSize.width == collectionView.contentOffset.x + self.view.frame.width
{
begin = true
}
}
func scrollViewDidEndScrollingAnimation(scrollView: UIScrollView) {
// Called when manually setting contentOffset
scrollViewDidEndDecelerating(scrollView)
}
}
This is my whole code.. I am not able to go to first cell after last cell. Please Help me.
Solution 1:[1]
Below is code you can try :
/**
Scroll to Next Cell
*/
func scrollToNextCell(){
//get Collection View Instance
let collectionView:UICollectionView;
//get cell size
let cellSize = CGSizeMake(self.view.frame.width, self.view.frame.height);
//get current content Offset of the Collection view
let contentOffset = collectionView.contentOffset;
//scroll to next cell
collectionView.scrollRectToVisible(CGRectMake(contentOffset.x + cellSize.width, contentOffset.y, cellSize.width, cellSize.height), animated: true);
}
/**
Invokes Timer to start Automatic Animation with repeat enabled
*/
func startTimer() {
let timer = NSTimer.scheduledTimerWithTimeInterval(1.0, target: self, selector: Selector("scrollToNextCell"), userInfo: nil, repeats: true);
}
Solution 2:[2]
For Swift4
override func viewDidLoad() {
super.viewDidLoad()
startTimer()
}
func startTimer() {
let timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(self.scrollAutomatically), userInfo: nil, repeats: true)
}
@objc func scrollAutomatically(_ timer1: Timer) {
if let coll = topMenuCollection {
for cell in coll.visibleCells {
let indexPath: IndexPath? = coll.indexPath(for: cell)
if ((indexPath?.row)! < banner.count - 1){
let indexPath1: IndexPath?
indexPath1 = IndexPath.init(row: (indexPath?.row)! + 1, section: (indexPath?.section)!)
coll.scrollToItem(at: indexPath1!, at: .right, animated: true)
}
else{
let indexPath1: IndexPath?
indexPath1 = IndexPath.init(row: 0, section: (indexPath?.section)!)
coll.scrollToItem(at: indexPath1!, at: .left, animated: true)
}
}
}
}
topMenuCollection :- your collection view
banner.Count:- a number of cells containing a collection view
Solution 3:[3]
Swift 3
This tested code scrolls to the next cell and returns to first item after the last one.
func setTimer() {
let _ = Timer.scheduledTimer(timeInterval: 3.0, target: self, selector: #selector(MainVC.autoScroll), userInfo: nil, repeats: true)
}
var x = 1
@objc func autoScroll() {
if self.x < self.storiesForCollectionView.count {
let indexPath = IndexPath(item: x, section: 0)
self.collectionViewUp.scrollToItem(at: indexPath, at: .centeredHorizontally, animated: true)
self.x = self.x + 1
}else{
self.x = 0
self.collectionViewUp.scrollToItem(at: IndexPath(item: 0, section: 0), at: .centeredHorizontally, animated: true)
}
}
override func viewDidLoad() {
super.viewDidLoad()
setTimer()
}
Solution 4:[4]
/**
Scroll to Next Cell
*/
func scrollToNextCell(){
//get cell size
let cellSize = CGSizeMake(self.view.frame.width, self.view.frame.height);
//get current content Offset of the Collection view
let contentOffset = collectionView.contentOffset;
if collectionView.contentSize.width <= collectionView.contentOffset.x + cellSize.width
{
collectionView.scrollRectToVisible(CGRectMake(0, contentOffset.y, cellSize.width, cellSize.height), animated: true);
} else {
collectionView.scrollRectToVisible(CGRectMake(contentOffset.x + cellSize.width, contentOffset.y, cellSize.width, cellSize.height), animated: true);
}
}
/**
Invokes Timer to start Automatic Animation with repeat enabled
*/
func startTimer() {
NSTimer.scheduledTimerWithTimeInterval(2.0, target: self, selector: Selector("scrollToNextCell"), userInfo: nil, repeats: true);
}
Solution 5:[5]
swift 4:
func scrollToNextCell(){
//get cell size
let cellSize = view.frame.size
//get current content Offset of the Collection view
let contentOffset = collectionView.contentOffset
if collectionView.contentSize.width <= collectionView.contentOffset.x + cellSize.width
{
let r = CGRect(x: 0, y: contentOffset.y, width: cellSize.width, height: cellSize.height)
collectionView.scrollRectToVisible(r, animated: true)
} else {
let r = CGRect(x: contentOffset.x + cellSize.width, y: contentOffset.y, width: cellSize.width, height: cellSize.height)
collectionView.scrollRectToVisible(r, animated: true);
}
}
Solution 6:[6]
Use your pagecontrol property and scrolltoitem.
func setuptimer() {
timer = Timer.scheduledTimer(timeInterval: 3, target: self , selector:
#selector(startScrolling), userInfo: nil, repeats: true)
}
@objc func startScrolling() {
if pageControl.currentPage == pageControl.numberOfPages - 1 {
pageControl.currentPage = 0
} else {
pageControl.currentPage += 1
}
<yourCollectionView>.scrollToItem(at: IndexPath(row: pageControl.currentPage, section: 0), at: .right, animated: true)
}
Solution 7:[7]
Here is my slightly improved solution. It stops the scroll when user manually starts to scroll and restarts it if the cell is reused again.
private var indexCurrentCell = 0
private weak var timer: Timer?
private var items = [Item]() {
didSet {
collectionView.reloadData()
indexCurrentCell()
}
}
private func startAutoscrolling() {
indexCurrentCell = 0
timer?.invalidate()
timer = Timer.scheduledTimer(withTimeInterval: 3, repeats: true) { [weak self] timer in
guard let self = self else {
timer.invalidate()
return
}
guard !self.items.isEmpty else {
return
}
if self.indexCurrentCell < self.items.count {
let indexPath = IndexPath(item: self.indexCurrentCell, section: 0)
self.collectionView.scrollToItem(at: indexPath, at: .centeredHorizontally, animated: true)
self.indexCurrentCell += 1
} else {
self.indexCurrentCell = 1
self.collectionView.scrollToItem(at: IndexPath(item: 0, section: 0), at: .centeredHorizontally, animated: true)
}
}
timer?.fire()
}
func scrollViewDidScroll(_ scrollView: UIScrollView) {
if scrollView.isTracking {
timer?.invalidate()
}
}
override func awakeFromNib() {
super.awakeFromNib()
startAutoscrolling()
}
Solution 8:[8]
try this
var index = 0
var inForwardDirection = true
var timer: Timer?
@objc func scrollToNextCell() {
//scroll to next cell
let items = collectionViewTable.numberOfItems(inSection: 0)
if (items - 1) == index {
collectionViewTable.scrollToItem(at: IndexPath(row: index, section: 0), at: UICollectionViewScrollPosition.right, animated: true)
} else if index == 0 {
collectionViewTable.scrollToItem(at: IndexPath(row: index, section: 0), at: UICollectionViewScrollPosition.left, animated: true)
} else {
collectionViewTable.scrollToItem(at: IndexPath(row: index, section: 0), at: UICollectionViewScrollPosition.centeredHorizontally, animated: true)
}
if inForwardDirection {
if index == (items - 1) {
index -= 1
inForwardDirection = false
} else {
index += 1
}
} else {
if index == 0 {
index += 1
inForwardDirection = true
} else {
index -= 1
}
}
}
/**
call this method when collection view loaded
*/
func startTimer() {
if timer == nil {
timer = Timer.scheduledTimer(timeInterval: 5.0, target: self, selector: #selector(scrollToNextCell), userInfo: nil, repeats: true);
}
}
Solution 9:[9]
I suggest using the collection view method scrollToItem(at:at:animated:) rather than scrollRectToVisible. It saves you from having to do calculations to figure out what rectangle to expose. You can just specify an indexPath to which you want to scroll.
Solution 10:[10]
/**
Scroll to Next Cell
*/
@objc func scrollToNextCell(){
//get cell size
let cellSize = CGSize(width:self.view.frame.size.width, height:viewForCV.frame.size.height)
//get current content Offset of the Collection view
let contentOffset = cvAdvertisements.contentOffset;
if cvAdvertisements.contentSize.width <= cvAdvertisements.contentOffset.x + cellSize.width
{
cvAdvertisements.scrollRectToVisible(CGRect(x:0, y:contentOffset.y, width:cellSize.width, height:cellSize.height), animated: true);
} else {
cvAdvertisements.scrollRectToVisible(CGRect(x:contentOffset.x + cellSize.width, y:contentOffset.y, width:cellSize.width, height:cellSize.height), animated: true);
}
}
/**
Invokes Timer to start Automatic Animation with repeat enabled
*/
func startTimer() {
Timer.scheduledTimer(timeInterval: 2.0, target: self, selector: #selector(LoginViewController.scrollToNextCell), userInfo: nil, repeats: true);
}
Solution 11:[11]
You can achieve that using this AutoScrollCollectionView cocoapod to scroll automatically within specific intervals
It is as simple as subclassing your collection view from AutoScrollCollectionView and call startAutoScrolling method as shown below
self.autoScrollCollectionView.startAutoScrolling(withTimeInterval: TimeInterval(exactly: 2.0)!)
self.autoScrollCollectionView.stopAutoScrolling()
Solution 12:[12]
In Swift 4 & above, I have added the following code and works perfectly fine. While we scroll manually the timer has stop and when end scrolling manually then timer again starts from last index scrolled.
Initialise the variable as:-
private var timer: Timer?
private var indexCurrentCell = 0
Then add following code in the class or extension as follows:-
func scrollViewWillBeginDragging(scrollView: UIScrollView) {
self.stopTimer()
}
func scrollViewDidEndDragging(scrollView: UIScrollView, willDecelerate decelerate: Bool) {
self.startTimerForAutoScroll()
}
private func startTimerForAutoScroll() {
self.startAutoScroll()
}
private func stopTimer() {
timer?.invalidate()
timer = nil
}
private func startAutoScroll() {
indexCurrentCell = 0
timer?.invalidate()
timer = Timer.scheduledTimer(withTimeInterval: 2, repeats: true) { [weak self] timer in
guard let self = self else {
timer.invalidate()
return
}
guard let offersDataArr = self.offersData, !offersDataArr.isEmpty else {
return
}
if self.indexCurrentCell < offersDataArr.count {
let indexPath = IndexPath(item: self.indexCurrentCell, section: 0)
self.offersCollectionView.scrollToItem(at: indexPath, at: .centeredHorizontally, animated: true)
self.indexCurrentCell += 1
} else {
self.indexCurrentCell = 1
self.offersCollectionView.scrollToItem(at: IndexPath(item: 0, section: 0), at: .centeredHorizontally, animated: true)
}
}
timer?.fire()
}
And call the function(startTimerForAutoScroll), from where the collection view array setup:-
override func viewDidLoad() {
super.viewDidLoad()
offersCollectionView.delegate = self
offersCollectionView.dataSource = self
startTimerForAutoScroll()
}
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow