collectionView 不 scrollToItem - swift - 以编程方式

Question

我以这种方式在 UIView 中设置了一个 UICollectionview：

videoCollectionView.delegate = self
videoCollectionView.dataSource = self
    
self.playerView.insertSubview(videoCollectionView, belowSubview: additionalItemsView)
videoCollectionView.fillSuperview()

这就是数据源和委托方法的实现方式

extension CardView : UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout{


func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    
    let numberOfURLS = cardModel?.urlStrings?.count
    return numberOfURLS!
}

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    
    let videoCell = collectionView.dequeueReusableCell(withReuseIdentifier: "videoCellIdentifier", for: indexPath)
    videoCell.backgroundColor = UIColor.random()
    
    return videoCell
    
}


func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    return CGSize(width: self.bounds.width, height: self.bounds.height)
}
}

从上面的代码可以看出，每个单元格的大小是 collectionView.frame 我想让 collectionView 单元格水平显示并能够滚动浏览它们。

这是我实现的水平滚动单元格的代码：

fileprivate func goToNextVideo(){
    
    counter = counter+1
    counter = min(cardModel!.urlStrings!.count-1, counter)
    
    videoCollectionView.scrollToItem(at: IndexPath(item: 0, section: counter), at: .left, animated: true) 
}


fileprivate func goToPreviousVideo(){
    
    counter = counter - 1
    counter = max(0, counter)

    videoCollectionView.scrollToItem(at: IndexPath(item: 0, section: counter), at: .left, animated: true)
}

我不知道为什么，collectionView 没有滚动到所需的单元格，我在控制台中收到此警告：

Warning: Invalid IndexPath <NSIndexPath: 0xa5dbc31284d24cfa> {length = 2, path = 1 - 0} specified - will use a contentOffset of {0,0} as a fallback value.

Answer 1

我觉得像

IndexPath(item: 0, section: counter)

向后（两次）。尝试

IndexPath(item: counter, section: 0)

在两个地方。

collectionView 不 scrollToItem - swift - 以编程方式

collectionView doesn't scrollToItem - swift - programmatically

swift

uicollectionview

collectionview

indexpath