UICollectionView indexPath.row奇怪的行为(UICollectionView indexPath.row strange behaviour)

 滚动我的一个collectionView时，我遇到了一个奇怪的问题。 当我打印indexPath.row从indexPath.row正常，但最后一个indexPath.row是3，然后如果我向后滚动它或者与excbadadress崩溃或以随机顺序打印1,2,4。 我假设我的代码中有错误但实际上不明白它在哪里。 这是我的代码：VC： 
 
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: IndexPath) -> CGSize {
    if collectionView == mainEventsCollectionView {
        return CGSize(width: UIScreen.main.bounds.width - 40, height: 180)
    } else {
        return CGSize(width: 150, height: 200)
    }
}

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    if collectionView == mainEventsCollectionView {
        return 3
    } else {
        return 7
    }
}

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    if collectionView == mainEventsCollectionView {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "mainEventsCell", for: indexPath) as! MainEventCollectionViewCell
        cell.eventTitle.text = "Hello world".uppercased()
        cell.setupCell()
        return cell
    } else {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "importantEventsCell", for: indexPath) as! ImportantEventsCollectionViewCell
        print(indexPath.row)
        cell.setupCell()
        return cell
    }
}
 
 细胞： 
 
required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    self.roundCorners(.allCorners, radius: 6, borderColor: .clear, borderWidth: 0)
}

func setupCell() {
    self.content.backgroundColor = colorWithAlpha(.black, alpha: 0.7)
    self.eventDate.textColor = .white
    self.eventTime.textColor = .white
    self.eventName.textColor = .white
    if self.content.layer.sublayers!.count > 3 {
        self.content.layer.sublayers!.removeLast()
    }
    if self.eventDate.text == "Today" {
        self.content.backgroundColor = .clear
        DispatchQueue.main.async(execute: {
            self.content.drawGradient(colors: [UIColor(red: 250/255, green: 217/255, blue: 97/255, alpha: 0.7).cgColor, UIColor(red: 255/255, green: 135/255, blue: 67/255, alpha: 0.7).cgColor], locations: [0, 1])
        })
        self.eventDate.textColor = .black
        self.eventTime.textColor = .black
        self.eventName.textColor = .black
    }
}

I'm having strange issue while scrolling one of my collectionViews. When I'm printing indexPath.row is goes ok from 0..6 but then last indexPath.row is 3, and then if I scroll back it either crashes with excbadadress or prints 1, 2, 4 in random order. I assume that I have and error in my code but really don't understand where is it. Here is my code: VC:
 
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: IndexPath) -> CGSize {
    if collectionView == mainEventsCollectionView {
        return CGSize(width: UIScreen.main.bounds.width - 40, height: 180)
    } else {
        return CGSize(width: 150, height: 200)
    }
}

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    if collectionView == mainEventsCollectionView {
        return 3
    } else {
        return 7
    }
}

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    if collectionView == mainEventsCollectionView {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "mainEventsCell", for: indexPath) as! MainEventCollectionViewCell
        cell.eventTitle.text = "Hello world".uppercased()
        cell.setupCell()
        return cell
    } else {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "importantEventsCell", for: indexPath) as! ImportantEventsCollectionViewCell
        print(indexPath.row)
        cell.setupCell()
        return cell
    }
}
 
Cell:
 
required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    self.roundCorners(.allCorners, radius: 6, borderColor: .clear, borderWidth: 0)
}

func setupCell() {
    self.content.backgroundColor = colorWithAlpha(.black, alpha: 0.7)
    self.eventDate.textColor = .white
    self.eventTime.textColor = .white
    self.eventName.textColor = .white
    if self.content.layer.sublayers!.count > 3 {
        self.content.layer.sublayers!.removeLast()
    }
    if self.eventDate.text == "Today" {
        self.content.backgroundColor = .clear
        DispatchQueue.main.async(execute: {
            self.content.drawGradient(colors: [UIColor(red: 250/255, green: 217/255, blue: 97/255, alpha: 0.7).cgColor, UIColor(red: 255/255, green: 135/255, blue: 67/255, alpha: 0.7).cgColor], locations: [0, 1])
        })
        self.eventDate.textColor = .black
        self.eventTime.textColor = .black
        self.eventName.textColor = .black
    }
}

原文：https://stackoverflow.com/questions/39722070