Question

我正在尝试更改集合视图单元格标签的文本大小，并且可以工作一些。当我选择明智的项目索引（单元格0，单元格1，单元格2 ...）时，它对我有用，但是当我尝试选择随机索引（例如：单元格0至单元格3）上的项目时，我的应用程序崩溃了

我正在尝试以下代码：

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath)  {
    let idxPath = IndexPath(item: indexPath.item, section: 0)
    let cell = collectionView.cellForItem(at: idxPath)
    let myCell = collectionView.cellForItem(at: idxPath) as! MenuCell
    cell?.isSelected = true
    myCell.isSelected = true
    myCell.title.font = UIFont.systemFont(ofSize: 16)
    collectionView.scrollToItem(at: idxPath, at: UICollectionViewScrollPosition.centeredHorizontally, animated: true)
}
func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
    let idxPath = IndexPath(item: indexPath.item, section: 0)
    let myCell = collectionView.cellForItem(at: idxPath) as! MenuCell
    myCell.isSelected = false
    myCell.title.font = UIFont.systemFont(ofSize: 13)
}

它在串联电池选择中起作用

enter image description here

但是当我随机选择单元格

enter image description here

谢谢，抱歉我的英语不好

Answer 1

因为您重新创建了IndexPath，然后对单元进行了强制解包。如果您只需要为第一部分更改字体，请尝试更改如下代码：

func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
    if indexPath.section == 0 {
      let myCell = collectionView.cellForItem(at: indexPath) as? MenuCell
       myCell?.isSelected = false
       myCell?.title.font = UIFont.systemFont(ofSize: 13)
    }
}

Answer 2

尝试一下...

var selectedCell = [Int]()

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: yourCellIdentifier, for: indexPath) as! MenuCell

    //Code for change font size

    if selectedCell.contains(indexPath.cell){
       cell.title.font = UIFont.systemFont(ofSize: 16)
    }else{
       cell.title.font = UIFont.systemFont(ofSize: 13)
    }

    return cell
}

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath)  {
    if selectedCell.contains(indexPath.item){
       selectedCell.remove(at: selectedCell.index(of: selectedCell.contains[indexPath.item])!)
    }else{
       selectedCell.append(indexPath.item)
    }
    collectionView.reloadData()
}

在UICollectionView中更改选定单元格的文本大小

2 个答案: