不能的CollectionView

Question

刪除項目我有簡單的CollectionView這表明在iphone 1列，並在iPad上

2列

有一個按鈕從的CollectionView刪除項目，但是當我按下按鈕，我得到這個錯誤：

The number of sections contained in the collection view after the update (3) must be equal to the number of sections contained in the collection view before the update (4), plus or minus the number of sections inserted or deleted (0 inserted, 0 deleted).'

這是我的代碼

protocol AudioListDataProtocol: class { 
    func search(searchText: String) 
    func playComposition(composition: Composition, data: [Composition], play: Bool) 
    func endEditing() 
} 

class AudioListDataAdapter: NSObject, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout, UISearchBarDelegate, AudioItemCellProtocol { 
    var delegate: AudioListDataProtocol! 
    var isFavoriesList = false 

    private var data = [Composition]() 
    private var collectionView: UICollectionView! 
    private var searchBar: UISearchBar! 
    private let cellIdentifier = "AudioCellIdent" 
    private var selectedIndexPath: IndexPath! 
    private var cellWidth = 0 as CGFloat 
    private var sectionCount = 0 
    private var itemCount = 0 


    //MARK: public methods 
    func initSearchBar(searchBar: UISearchBar) -> Void { 
     self.searchBar = searchBar 
     self.searchBar.delegate = self 
     self.searchBar.returnKeyType = .done 
     self.searchBar.placeholder = DicionaryManager.shared.getStringValue(dKey: AMKeys.mobile_label_search_here) 
    } 

    func initCollection(collection: UICollectionView) -> Void { 
     self.collectionView = collection 
     self.collectionView.dataSource = self 
     self.collectionView.delegate = self 
     self.collectionView.register(UINib.init(nibName: "AudioItemCell", bundle: nil), forCellWithReuseIdentifier: cellIdentifier) 
    } 

    func setListData(data: [Composition], itemsPerSection: Int, itemWidth: CGFloat) -> Void { 
     cellWidth = itemWidth 
     self.data = data 
     itemCount = itemsPerSection 
     sectionCount = Int(ceil(Double(self.data.count/itemCount))) 
    } 

    func reload() { 
     collectionView.reloadData() 
    } 


    //MARK: UISearchBarDelegate 
    func searchBarTextDidBeginEditing(_ searchBar: UISearchBar) { 
     searchBar.showsCancelButton = true 
    } 

    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) { 
     if searchText.characters.count >= 3 { 
      if let d = delegate { 
       d.search(searchText: searchText) 
      } 
     } 
    } 

    func searchBarCancelButtonClicked(_ searchBar: UISearchBar) { 
     searchBar.text = "" 
     if let d = delegate { 
      d.search(searchText: "") 
      d.endEditing() 
     } 
    } 

    func searchBarSearchButtonClicked(_ searchBar: UISearchBar) { 
     if let d = delegate { 
      d.endEditing() 
     } 
    } 


    //MARK: UICollectionViewDataSource 
    func numberOfSections(in collectionView: UICollectionView) -> Int { 
     return sectionCount 
    } 

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int { 
     return itemCount 
    } 

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell { 
     if let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdentifier, for: indexPath) as? AudioItemCell { 
      return cell 
     } 
     return UICollectionViewCell() 
    } 

    func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) { 
     let c = cell as! AudioItemCell 
     c.setupComposition(composition: data[curItemIndex(indexPath: indexPath)]) 
     c.indexPath = indexPath 
     c.favoriteState = isFavoriesList 
     c.delegate = self 
    } 

    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) { 
     PlayerManager.shared.changePlaylist() 
     var item: Composition 
     item = data[curItemIndex(indexPath: indexPath)] as Composition 
     item.isPlaying = true 
     item.showPlayer = true 
     collectionView.reloadItems(at: [indexPath]) 
     selectedIndexPath = indexPath 
     delegate.playComposition(composition: item, data: data, play: true) 
    } 

    func playingCompositionForReload(composition: Composition) { 
     composition.isPlaying = true 
     composition.showPlayer = true 
     collectionView.reloadData() 
    } 


    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize { 
     return CGSize(width: cellWidth, height: 90) 
    } 


    //MARK: helpers methods 
    func updateState(play: Bool) -> Void { 
     if (selectedIndexPath) != nil { 
      let item = data[curItemIndex(indexPath: selectedIndexPath)] 
      item.isPlaying = !item.isPlaying 
     } else { 
      selectedIndexPath = IndexPath(row: 0, section: 0) 
      let item = data[0] 
      item.isPlaying = true 
      item.showPlayer = true 
     } 

     collectionView.reloadItems(at: [selectedIndexPath]) 
    } 


    private func curItemIndex(indexPath: IndexPath) -> Int { 
     return indexPath.section * itemCount + indexPath.item 
    } 


    //MARK: AudioItemCellProtocol 
    func removeCellAtIndexpath(indexPath: IndexPath) { 
     collectionView.performBatchUpdates({ 
         self.data.remove(at: self.curItemIndex(indexPath: indexPath)) 
      sectionCount = Int(ceil(Double(self.data.count/self.itemCount))) 
      self.collectionView.deleteItems(at: [indexPath]) 
     }, completion: nil) 
    } 
} 

，這個按鈕按下代碼

delegate.removeCellAtIndexpath(indexPath: indexPath) 

我在這裏做錯了什麼，爲什麼它崩潰？

請幫助我堅持這一天。

Answer 1

問題出在您的numberOfItemsInSection方法和使用itemCount屬性。你正在返回一個固定的號碼。你假設每個部分都有相同的固定數量的項目。相反，您應該返回給定部分的數據源中的當前記錄數。

如果將數據源設置爲數組數組，其中外部數組表示您的部分，並且每個內部數組都是該部分中的項目，這將有很大幫助。然後你只需返回數組數而不是某個預定的變量。