CollectionView自动快速移动到下一个单元格

Question

我正在尝试创建像Flipkart一样的水平滑块.我正在使用带有水平滚动和分页的collectionView.单元格包含imageView.我成功地手动水平滚动项目,但我希望所有这些项目都自动和手动移动.我没有得到如何自动滚动collectionView的项目.请指导我这样做.

我在viewDidAppear中使用了这段代码:

let visibleIndexPath: NSIndexPath = self.collectionView.indexPathForCell(cell)!

self.collectionView.scrollToItemAtIndexPath(visibleIndexPath,  
atScrollPosition: UICollectionViewScrollPosition.CenteredHorizontally, animated: true)

谢谢.

编辑:

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)

    }

}

这是我的全部代码..我无法在最后一个单元格后进入第一个单元格.请帮我.

Answer 1

以下是您可以尝试的代码:

    /**
     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);


    }

Answer 2

对于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：-您的收藏夹视图

banner.Count：-包含集合视图的多个单元格

Answer 3

斯威夫特3

此测试代码滚动到下一个单元格并返回到最后一个单元格后的第一个项目.

     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()
    }

Answer 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);
}

Answer 5

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)
}