swift - CollectionView 自动快速移动到下一个单元格

Question

我正在尝试创建像 Flipkart 这样的水平 slider 。我正在使用具有水平滚动和分页功能的 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。我不知道如何自动滚动 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之后转到第一个单元格。请帮助我。

Answer 1

下面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);


    }