ios - af_setImage - 展开可选值时意外发现 nil

Question

我想从服务器端加载图像，但 af_setImage 显示此错误:

fatal error: unexpectedly found nil while unwrapping an Optional value

我的代码:

override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath as IndexPath) as! SupportersCollectionViewCell


    let url_img = URL(string: self.titles[indexPath.row])!

    print(url_img)//it returns correct value like http://kashanmap.ir/images/apk_images/hamian/hamian2.png

    cell.img_main.af_setImage(
        withURL: url_img
    )


    return cell
}

我的自定义单元格:

import UIKit
import Alamofire
import AlamofireImage
class SupportersCollectionViewCell: UICollectionViewCell {


    @IBOutlet weak var img_main: UIImageView!
}

已更新

我的 ImageView 返回 null:

if(cell.img_main == nil) { 打印(“测试”) }

Answer 1

试试这个:

    cell.img_main.image = nil

    if let url_img = URL(string: self.titles[indexPath.row])
    {
       cell.img_main.af_setImage(withURL: url_img)
    }
    else
    {
        print("error!")
    }

这样，错误就不会导致您的应用程序崩溃。