Question

我在数组中有200个项目，我正在传递到集合视图在设备上运行时，由于内存警告，它会崩溃。有没有办法根据滚动将单元格限制在索引路径的行。由于下载图像，它显示内存警告。如果我跳过下载部分，那么它就不会崩溃。

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    var cell:ProductListCell? = collectionView.dequeueReusableCell(withReuseIdentifier: "ProductListCell", for: indexPath) as? ProductListCell

    if (cell == nil) {
        let nib: NSArray = Bundle.main.loadNibNamed("ProductListCell", owner: self, options: nil)! as NSArray
        cell = (nib.object(at: 0) as? ProductListCell)!
        cell?.layer.shouldRasterize = true
        cell?.layer.rasterizationScale = UIScreen.main.scale;
    }

        if let url = NSURL(string: ((self.objCategorywiseResponse.SimilirProductsList![indexPath.row].productPic)!)) {
            cell?.imgProduct.sd_setImage(with: url as URL, placeholderImage: UIImage(named: "placeholder.png"))
        }

    if let strProductName = self.objCategorywiseResponse.SimilirProductsList![indexPath.row].ProductName {
        cell?.lblProductName.text = strProductName
    }

    cell?.lblProductDesc .text = ""

    if let strProductPrice = self.objCategorywiseResponse.SimilirProductsList![indexPath.row].MRP {
        cell?.lblProductPrice.attributedText = Common().setPrice(Price:strProductPrice, StrikePrice1:(self.objCategorywiseResponse.SimilirProductsList![indexPath.row].discountprice)!)
    }

    if let strDiscount = self.objCategorywiseResponse.SimilirProductsList![indexPath.row].DiscountPercentage {
        if strDiscount > 0 {
            cell?.btnDiscount.setTitle("\(strDiscount)% off", for: .normal)
        } else {
            cell?.btnDiscount.isHidden = true
        }
    }

    if let strRatingDesc = self.objCategorywiseResponse.SimilirProductsList![indexPath.row].TotalRating_Reviews {
        cell?.lblRatingdesc.text = strRatingDesc
    }

    if let strRating = self.objCategorywiseResponse.SimilirProductsList![indexPath.row].AvgRatingCount {
        cell?.lblRating.text = "\(strRating)"
    }

    if let intRating = self.objCategorywiseResponse.SimilirProductsList![indexPath.row].AvgRatingCount {
        cell?.subViewRating.rating = intRating
    }

    if let strShopName = self.objCategorywiseResponse.SimilirProductsList![indexPath.row].ShopName {
        cell?.lblShopName.text = strShopName
    }

    if let strDisctance = self.objCategorywiseResponse.SimilirProductsList![indexPath.row].Distance {
        cell?.lblDistance.setTitle("\(strDisctance) km near by you", for: .normal)
    }

    if let strLandLineNo = self.objCategorywiseResponse.SimilirProductsList![indexPath.row].LandLineNumber {
        cell?.lblMobileNo.text = "\(strLandLineNo)"
    }

    cell?.btnAddToCompare.tag = indexPath.row
    cell?.btnAddToCompare.addTarget(self, action: #selector(btnClickedAddToCompare(_:)), for: .touchUpInside)

    cell?.btnAddProduct.tag = indexPath.row
    cell?.btnAddProduct.addTarget(self, action: #selector(btnClickedAddProduct(_:)), for: .touchUpInside)

    cell?.btnCall.tag = indexPath.row
     cell?.btnCall.addTarget(self, action: #selector(self.callCellactn(_:)), for: .touchUpInside)

    cell?.btnMap.tag = indexPath.row
     cell?.btnMap.addTarget(self, action: #selector(self.locationCellactn(_:)), for: .touchUpInside)

    return cell!
}

Answer 1

我不认为细胞数量是个问题。 UICollectionView自动管理单元格集合，包括处理屏幕外单元格。

我认为您更有可能遇到内存泄漏，这会阻止在UICollectionView释放它们时实际取消分配单元格。你有很多块可能导致内存泄漏。

Answer 2

您可以使用分页概念一次停止加载所有单元格。它取消了可重用单元的高内存使用率。

检查这个link将详细说明使用分页概念。

Answer 3

您没有正确地重用作为内存警告原因的单元格删除这个`

if (cell == nil) {
    let nib: NSArray = Bundle.main.loadNibNamed("ProductListCell", owner: self, options: nil)! as NSArray
    cell = (nib.object(at: 0) as? ProductListCell)!
}

` 在viewDidLoad中使用以下代码

 self.collectionView.register(UINib.init(nibName: "ProductListCell", bundle: nil), forCellWithReuseIdentifier: "ProductListCell")

如果问题仍然存在，请使用以下库进行图像缓存 Kingfisher

它是一个内存影响较小的轻量级库

Answer 4

我在ScrollView中放置了Collection View这就是为什么它一次调用所有100个单元格。然后我删除了滚动视图然后它工作正常

限制一次加载的单元格的集合视图数量的方法

4 个答案: