一个 Viewcontroller 中的多个 collectionview 导致 Index out of range 错误

Posted 2023-03-08

【中文标题】一个 Viewcontroller 中的多个 collectionview 导致 Index out of range 错误

【英文标题】：Multiple collectionviews in one Viewcontroller causes Index out of range error

【发布时间】：2018-12-21 21:46:53

【问题描述】：

我尝试在一个视图控制器中使用三个集合视图。我像以下方法所示解析数据： 在底部，我根据位置将数据添加到右侧列表（这部分有效）

 func getEventData(eventIDs: [String], plz: String, positiona: Int)


        for eventId in eventIDs 
        let ref = Database.database().reference().child("Events").child(plz).child(eventId)
         ref.observe(.value, with:  snapshot in
            let item = snapshot.value as? [String: AnyObject]
            let eventName = item?["name"] as! String
            let date = item?["date"] as! String
            let lat = item?["lat"] as! String
            let lng = item?["lng"] as! String
            let infos = item?["additionalInfos"] as! String
            let position = item?["position"] as! String
            let ts = item?["ts"] as! Int
            let createdBy = item?["createdBy"] as! String

         let timestamp = NSDate().timeIntervalSince1970
            if (ts > Int(timestamp)) 
                let eo = EventObject(eventID: eventId, eventName: 
   eventName, info: infos, createdBy: createdBy, date: date, lat: lat, lng: lng, position: position, ts: ts)
                if positiona == 0
                    self.acceptedEvents.append(eo)
                    self.acceptedEventscv.reloadData()

                else if positiona == 1
                    self.myEvents.append(eo)
                    self.myEventscv.reloadData()

                else if positiona == 2
                   self.storedEvents.append(eo)
                self.storedEventscv.reloadData()
                
            

         )
        
    

在我的 NumbersofItemsInSection 方法中，我执行了以下操作：

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int 
    if collectionView == self.acceptedEventscv
    return acceptedEvents.count
    else if collectionView == self.storedEventscv
        return storedEvents.count
    else if collectionView == self.myEventscv
        return myEvents.count
    else
        return 0
    
    

在我的 CellForRowAtItem 方法中，我尝试了以下方法

func collectionView(_ collectionView: UICollectionView, 
 cellForItemAt indexPath: IndexPath) -> UICollectionViewCell 
 if collectionView == self.acceptedEventscv
 let cell = 
  collectionView.dequeueReusableCell(withReuseIdentifier: 
"acceptedEventsCell", for: indexPath) as! 
 acceptedEventsCollectionViewCell
 let eo = acceptedEvents[indexPath.row]
  cell.eventName.text = eo.eventName

  let items = eo.date!.components(separatedBy: " ")//Here replase 
  space with your value and result is Array.
 //Direct line of code
 //let items = "This is my String".components(separatedBy: " ")
 let date = items[0]
let time = items[1]
cell.date.text = date
cell.time.text = time

getUserNameAge(label: cell.usernameAge)
return cell
else 
  let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "savedEventsCell", for: indexPath) as! savedEventsCollectionViewCell
  let eo = acceptedEvents[indexPath.row]
  cell.eventName.text = eo.eventName

  let items = eo.date!.components(separatedBy: " ")//Here replase space with your value and result is Array.
  //Direct line of code
  //let items = "This is my String".components(separatedBy: " ")
  let date = items[0]
  let time = items[1]
  cell.date.text = date
  cell.time.text = time


  getUserNameAge(label: cell.usernameAge)

  return cell

问题是，如果我在第二个 CollectionView 中有更多项目，我总是会收到此错误：

线程 1：致命错误：索引超出范围

在这行代码：

let eo = acceptedEvents[indexPath.row]

【参考方案1】：

cellForItemAt也一定是这样的

if collectionView == self.acceptedEventscv
  let item = acceptedEvents[indexPath.row]
   ----
  return cell
else if collectionView == self.storedEventscv
    let item = storedEvents[indexPath.row]   
    ----
    return cell
else 
     let item = myEvents[indexPath.row] 
     ----
     return cell  

在您的情况下，现在发生的情况是，在 numberOfItemsInSection 中返回的计数可能不同的两种情况下，您都访问了相同的数组 acceptedEvents