swift - iOS - 将字符串转换为 double

Question

所以我正在从 fire base 配置数据中获取并尝试这样操作它。

这是我的结构:

struct FireBaseConfiguration: Codable {
 var updateTime: String = ""
 var iOSMinVersionForceUpdate: String = ""
 var iOSMinVersionMessageUpdate: String = ""
 var iOSMinFirmwareVersion: String = ""
 var privacyPolicyUrlFireBase: String = ""
 var termOfUseUrlFireBase: String = ""
}

这是我的解析器方法:

func fireBaseConfigVersionMapParser(dataString: String, version: String) -> FireBaseConfiguration? {

    var fireBaseConfiguration: FireBaseConfiguration?

    let data = dataString.data(using: .utf8)!

    do {
        if let jsonArray = try JSONSerialization.jsonObject(with: data, options : .allowFragments) as? NSDictionary {

           let model = jsonArray.object(forKey: version)

            let data = try JSONSerialization.data(withJSONObject: model!, options: .prettyPrinted)

            do {
             let parsedModel = try JSONDecoder().decode(FireBaseConfiguration.self, from: data)
                print("parsedModel is: \(parsedModel)")
                fireBaseConfiguration = parsedModel
            } catch let error{
                print(error)
            }
        } else {
            print("bad json")
        }

    } catch let error{
        print(error)
    }
    return fireBaseConfiguration
}

这是vc中的实现:

 self.remoteConfig?.fetch(withExpirationDuration: 0, completionHandler: { [unowned self] (status, error) in
        if status == .success {
            self.remoteConfig?.activateFetched()

            guard let configVersionMap = self.remoteConfig?.configValue(forKey: "iOSConfigVersionMap").stringValue else { return }

            if let configModel = self.parser.fireBaseConfigVersionMapParser(dataString: configVersionMap, version: self.getCurrentAppVersion()!) {

                print(configModel)
                print(configModel.iOSMinVersionForceUpdate)
                print(configModel.iOSMinVersionMessageUpdate)
                                    var doubleForceUpdate = Double(configModel.iOSMinVersionForceUpdate)
                var doubleMessageUpdate = Double(configModel.iOSMinVersionMessageUpdate)

                print(doubleForceUpdate)
                print(doubleMessageUpdate)

            }
      } else {
                  print("Config not fetched")
                  print("Error: \(error?.localizedDescription ?? "No error available.")")
        }
    })

所以打印品是这样的:

FireBaseConfiguration(更新时间:“13/7/2018”，iOSMinVersionForceUpdate:“1.0.2”，iOSMinVersionMessageUpdate:“1.0.2”，iOSMinFirmwareVersion:“1.0.1”，privacyPolicyUrlFireBase:“https://www.name.com/corporate/privacy-policy”，termOfUrlFireBase:“https://www.name.com/corporate/terms-of-use ")

1.0.21.0.2零无

有什么想法吗？

Answer 1

它是一个简单的 String，但它实际上不是一个有效的 Double(Double 值没有两位小数)。所以这就是它失败的原因。

我认为您真正需要的是比较版本号的能力，网站上还有许多其他答案可以告诉您如何做到这一点:

• Compare two version strings in Swift
• Compare version numbers in Objective-C

所以你可以将你的版本号保存为 String