Question

当UICollectionView滚动时，单元格的选择会发生变化。以下是我正在做的，请检查下面提到的代码。我选择第0部分中有多个单元格的单元格和第1部分只有一个单元格的单元格。因此，在选择第1节单元格时，第0节中的所有选择都将变得清晰。此功能正在运行，但滚动选择会发生变化。

func initUI()
{
   self.collectionViewBrands!.registerClass(SignupStep3CollectionViewCell.self, forCellWithReuseIdentifier: "cell")

    let nibName = UINib(nibName: "SignupStep3CollectionViewCell", bundle:nil)
    self.collectionViewBrands.registerNib(nibName, forCellWithReuseIdentifier: "cell")

    self.collectionViewBrands.allowsMultipleSelection = true
}

func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
     return 2
}

func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    if section == 0
    {
        return self.arrItems.count
    }
    else
    {
        return 1
    }
}

func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAtIndex section: Int) -> UIEdgeInsets {

    if section == 1
    {
        let flowLayout = (collectionViewLayout as! UICollectionViewFlowLayout)
        let cellSpacing = flowLayout.minimumInteritemSpacing
        let cellWidth = flowLayout.itemSize.width
        let cellCount = CGFloat(collectionView.numberOfItemsInSection(section))

        let totalCellWidth = cellWidth * cellCount
        let totalSpacingWidth = cellSpacing * (cellCount - 1)

        let leftInset = (self.collectionViewBrands.frame.size.width - CGFloat(totalCellWidth + totalSpacingWidth)) / 2;
        let rightInset = leftInset

        return UIEdgeInsetsMake(0, leftInset, 0, rightInset)
    }
    else
    {
        return UIEdgeInsetsMake(0, 0, 28, 0)
    }
}

// make a cell for each cell index path
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

    // get a reference to our storyboard cell

    let cell = collectionView.dequeueReusableCellWithReuseIdentifier("cell", forIndexPath: indexPath) as! SignupStep3CollectionViewCell

    // Use the outlet in our custom class to get a reference to the UILabel in the cell
    if indexPath.section == 0
    {
        cell.contentView.backgroundColor = UIColor.whiteColor()
        cell.lblNone.hidden = true
        cell.imgBrands.backgroundColor = UIColor.clearColor()
        cell.imgBrands.image = UIImage(named: "logo_sample")
    }
    else
    {
        cell.contentView.backgroundColor = UIColor.clearColor()
        cell.imgBrands.image = UIImage(named: "")
        cell.lblNone.hidden = false
        cell.lblNone.backgroundColor = UIColor.clearColor()
        cell.lblNone.text = "None"
    }
    return cell
}

func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath){

    let cell = collectionView.cellForItemAtIndexPath(indexPath) as! SignupStep3CollectionViewCell

    cell.layer.borderWidth = 4
    cell.layer.masksToBounds = false
    cell.layer.borderColor = UIColor.init(red: 46.0/255.0, green: 234.0/255.0, blue: 219.0/255.0, alpha: 1.0).CGColor
    cell.layer.cornerRadius = cell.frame.height/2
    cell.clipsToBounds = true

    if indexPath.section == 0
    {
          self.arrSelectedItems.addObject(self.arrItems.objectAtIndex(indexPath.row))

        let indexSet = NSIndexSet(index: 1)
        self.collectionViewBrands.reloadSections(indexSet)
    }
    if indexPath.section == 1
    {
        let indexSet = NSIndexSet(index: 0)
        self.arrSelectedItems.removeAllObjects()
        self.collectionViewBrands.reloadSections(indexSet)
    }
}

请指出上面的错误。并随意询问是否有任何不清楚的事情。

Answer 1

问题在于，由于UICollectionView的单元重用机制，您不能保证在给定的索引路径上获得相同的单元实例，因此您在{{1}中进行了配置可能会迷路。

您可以通过在didSelectItemAtIndexPath：

中配置单元格选择外观和感觉来解决问题

cellForItemAtIndexPath

在swift 2中滚动时，UICollectionView更改单元格数据

1 个答案: