swift - 如何使用swift中的计数数组移动到下一个对象？

Question

我正在使用 uicollectionview 进行无限滚动。但是我正在尝试当用户单击“下一步”(按钮)时应该更改为下一个对象。喜欢

我有一个像 "arrayOfItems = ["Apple","Ball","Cat","Rat"]” 这样的数组

如果在 Collection View Cell 中，我在标签中显示“Apple”。

如果我点击下一个按钮，“球”就来了。

如果我再次点击下一个按钮，它不会滚动到下一个对象。

我的代码是这样的:

   func reversePhotoArray(arrayItems:[String], startIndex:Int, endIndex:Int){
        if startIndex >= endIndex{
            return
        }
        swap(&arrayOfItems[startIndex], &arrayOfItems[endIndex])

        reversePhotoArray(arrayOfItems, startIndex: startIndex + 1, endIndex: endIndex - 1)
    }

}
  @IBAction func nextButtonMethod(sender: AnyObject) {


      //   let fullyScrolledContentOffset:CGFloat = infiniteScrollingCollectionView.frame.size.width * CGFloat(photosUrlArray.count - 1)


        //  reversePhotoArray(photosUrlArray, startIndex:  0 + 1, endIndex: photosUrlArray.count - 1)


            reversePhotoArray(arrayOfItems, startIndex: 0, endIndex: photosUrlArray.count - 1)
            reversePhotoArray(arrayOfItems, startIndex: 0, endIndex: 1)

            reversePhotoArray(arrayOfItems, startIndex: 2, endIndex: arrayOfItems.count - 1)
        reversePhotoArray(arrayOfItems, startIndex: 0, endIndex: arrayOfItems.count - 1)
        reversePhotoArray(arrayOfItems, startIndex: 0, endIndex: arrayOfItems.count - 3)
        reversePhotoArray(arrayOfItems, startIndex: arrayOfItems.count - 2, endIndex: arrayOfItems.count - 1)
            let indexPath : NSIndexPath = NSIndexPath(forRow: 1, inSection: 0)
            infiniteScrollingCollectionView.scrollToItemAtIndexPath(indexPath, atScrollPosition: .Left, animated: false)



//            let indexPath : NSIndexPath = NSIndexPath(forRow: photosUrlArray.count - 2, inSection: 0)
//            infiniteScrollingCollectionView.scrollToItemAtIndexPath(indexPath, atScrollPosition: .Left, animated: false)



    }


extension InfiniteScrollingViewController : UICollectionViewDataSource{

    func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {

        return 1

    }



    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {

        return arrayOfItems.count

    }



    func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

        let cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath) as! InfiniteScrollingCell

        let photoName = photoForIndexPath(indexPath)

        cell.label.text = photoName

     cell.configureCell(photoName)



        return cell

    }

}

谁能帮我解决这个问题。我在这里犯了什么错误。

提前致谢。

Answer 1

你的下一个按钮总是滚动到第 1 行。
试试这个:

var nextRow = 1

@IBAction func nextButtonMethod(sender: AnyObject) {

  //   let fullyScrolledContentOffset:CGFloat = infiniteScrollingCollectionView.frame.size.width * CGFloat(photosUrlArray.count - 1)

     //  reversePhotoArray(photosUrlArray, startIndex:  0 + 1, endIndex: photosUrlArray.count - 1)


    reversePhotoArray(arrayOfItems, startIndex: 0, endIndex: photosUrlArray.count - 1)
    reversePhotoArray(arrayOfItems, startIndex: 0, endIndex: 1)

    reversePhotoArray(arrayOfItems, startIndex: 2, endIndex: arrayOfItems.count - 1)
    reversePhotoArray(arrayOfItems, startIndex: 0, endIndex: arrayOfItems.count - 1)
    reversePhotoArray(arrayOfItems, startIndex: 0, endIndex: arrayOfItems.count - 3)
    reversePhotoArray(arrayOfItems, startIndex: arrayOfItems.count - 2, endIndex: arrayOfItems.count - 1)

    if nextRow < arrayOfItems.count {
        let indexPath : NSIndexPath = NSIndexPath(forRow: nextRow, inSection: 0)
        infiniteScrollingCollectionView.scrollToItemAtIndexPath(indexPath, atScrollPosition: .Left, animated: false)
        nextRow += 1
    }

//            let indexPath : NSIndexPath = NSIndexPath(forRow: photosUrlArray.count - 2, inSection: 0)
//            infiniteScrollingCollectionView.scrollToItemAtIndexPath(indexPath, atScrollPosition: .Left, animated: false)



}