swift - 网址错误 : Unexpectedly found nil while unwrapping an Optional value: file

Question

我正在使用 WinguGallery pod。我想查看我从 MSSQL 与 wingugallerry 拍摄的链接中的照片。我可以成功提取数据。但是“让 asset = ImageAsset (url: url!)我在“我成功从数据库中检索数据。但可能在 url 部分定义变量时。我获取的数据是字符串变量。

import UIKit
import WinguGallery

class GelisimController: UIViewController {
func fillWithGifs() {

        let client = SQLClient.sharedInstance()!
  client.connect("ddd", username: "ddd", password: "ddd", database: "ddd") { success in
             client.execute("SELECT ddd FROM ddd", completion: { (_ results: ([Any]?)) in
                                                    var gifsa: [String] = []
                             for table in results as! [[[String:AnyObject]]] {

                               for row in table {

                                    for (_, value) in row {

                                    if let intVal = value as? String {
                                gifsa.append(String(intVal))
                               var returnArray: [ImageAsset?] = [ImageAsset]()
                                            for item in gifsa {
                                            let url = URL(string: item)
                                            let asset = ImageAsset(url: url!) //error line
                                           returnArray.append(asset)
                                                                }
                                        self.winguGalleryView.assets = returnArray
                                        print("returnArray", gifsa)
                                                                }} }}
                                        client.disconnect()
                                          })}
       }

Answer 1

像这样修改你的 for 循环

for item in gifsa {
   guard let url = URL(string : item) else {continue}
   //Rest of the code here
}

如果您不确定这些值，请不要强行打开包装。 :)