Question

我有以下布局：当滚动tableView fps下降到25左右时，它变得非常抖动。

我认为这是我对collectionView的实现，因为很多操作都是在cellForIndexAtPath中执行的。但我看不出可以优化什么？

extension MyTableViewController: UICollectionViewDelegate, UICollectionViewDataSource {

func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int
{
    // No sections are longer than 99
    if(collectionView.tag < 100)
    {
        let code = codes0[collectionView.tag].objectForKey("code") as! String

        return code.componentsSeparatedByString(",").count
    }
    else if(collectionView.tag < 200)
    {
        let code = codes1[collectionView.tag-100].objectForKey("code") as! String

        return code.componentsSeparatedByString(",").count
    }
    else
    {
        let code = codes2[collectionView.tag-200].objectForKey("code") as! String

        return code.componentsSeparatedByString(",").count
    }
}

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell
{
    let cell = collectionView.dequeueReusableCellWithReuseIdentifier("code", forIndexPath: indexPath) as! ImageCodeCollectionViewCell

    // Read that this should help for GPU
    cell.layer.shouldRasterize = true
    cell.layer.rasterizationScale = UIScreen.mainScreen().scale

    var codeLength:String! = ""

    if(collectionView.tag < 100)
    {
        codeLength = self.codes0[collectionView.tag].objectForKey("code") as! String
    }
    else if(collectionView.tag < 200)
    {
        codeLength = self.codes1[collectionView.tag-100].objectForKey("code") as! String
    }
    else
    {
        codeLength = self.codes2[collectionView.tag-200].objectForKey("code") as! String
    }

    let cLength = codeLength.componentsSeparatedByString(",")

    if(indexPath.row <= cLength.count)
    {
        cell.imageCode.image = UIImage(named: cLength[indexPath.row])
    }

    return cell
}

我的tableView看起来像是：

这是collectionView数据源和委托集

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
{
    let cell = tableView.dequeueReusableCellWithIdentifier("cheat") as! CodeTableViewCell

    cell.layer.shouldRasterize = true
    cell.layer.rasterizationScale = UIScreen.mainScreen().scale

    cell.setCollectionViewDataSourceDelegate(self, forRow: indexPath.row, forSection: indexPath.section)

    return cell
}

func tableView(tableView: UITableView, willDisplayCell cell: CodeTableViewCell, forRowAtIndexPath indexPath: NSIndexPath)
{
    switch indexPath.section
    {
    case 2:
        cell.name = codes2[indexPath.row].objectForKey("name") as! String

        cell.descript = ((codes2[indexPath.row].objectForKey("description") as! String).isEmpty ? "-" : codes2[indexPath.row].objectForKey("description") as! String)

    case 1:
        cell.name = codes1[indexPath.row].objectForKey("name") as! String

        cell.descript = ((codes1[indexPath.row].objectForKey("description") as! String).isEmpty ? "-" : codes1[indexPath.row].objectForKey("description") as! String)

    default:
        cell.name = codes0[indexPath.row].objectForKey("name") as! String

        cell.descript = ((codes0[indexPath.row].objectForKey("description") as! String).isEmpty ? "-" : codes0[indexPath.row].objectForKey("description") as! String)
    }
}

Answer 1

通过简要地查看您的代码，只需UICollectionView设置就可以使用UICollectionReusableView作为标题，就可以了。这样，所有collectionViews都会重复使用相同的cells，并且每次collectionViews变为可见时您都不必布置UITableViewCell。

此外，您可能会考虑将code.componentsSeparatedByString(",").count等操作的结果存储在单独的变量中，并且只在数据更改后才计算出来。

具有collectionView性能问题的TableView单元格

1 个答案: