Question

之前我有这个工作，但看起来在Xamarin或Android SDK中有些变化。我试图用反序列化的json数据填充一个微调器。然而，微调器适配器不再接受我的列表了？它说我无法从对象转换为int？我在here

之前遵循的教程

    Spinner spinner;
    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);

        SetContentView(Resource.Layout.Main);

        string urlmountains = "http://my.azurewebsites.net/api/Mountains";

        JsonValue json1 = FetchMountains(urlmountains);

        var list = JsonConvert.DeserializeObject<List<RootObject>>(json1.ToString());

        spinner = FindViewById<Spinner>(Resource.Id.spinner1);
        //this line ------------------------------------------------->
        spinner.Adapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleSpinnerDropDownItem, list); // Error here cannot convert from Object to Int?

    }


    private JsonValue FetchMountains(string urlmountains)
    {
        // Create an HTTP web request using the URL:
        HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(new Uri(urlmountains));
        request.ContentType = "application/json";
        request.Method = "GET";

        // Send the request to the server and wait for the response:
        using (WebResponse response = request.GetResponse())
        {
            // Get a stream representation of the HTTP web response:
            using (Stream stream = response.GetResponseStream())
            {
                // Use this stream to build a JSON document object:
                JsonValue jsonDoc1 = JsonObject.Load(stream);
                Console.Out.WriteLine("Response: {0}", jsonDoc1.ToString());

                // Return the JSON document:
                return jsonDoc1;
            }
        }
    }
    public class RootObject
    {
        public string ID { get; set; }

        public double? Latitude { get; set; }

        public double? Longitude { get; set; }

        public string Name { get; set; }

        public double? Height_m { get; set; }

        public double? Height_ft { get; set; }

        public double? temperature { get; set; }

        public double? humidity { get; set; }

        public double? snowCover { get; set; }
    }
}

Answer 1

您的list是List的{{1}}：

RootObject

但是您的var list = JsonConvert.DeserializeObject<List<RootObject>>(...);想要ArrayAdapter List：

string

您的IDE无法解析相应的构造函数，因为这些类型不匹配。将您的spinner.Adapter = new ArrayAdapter<string>(...);类型参数更改为ArrayAdapter：

RootObject

此外，spinner.Adapter = new ArrayAdapter<RootObject>(...);显示其模型类的ArrayAdapter方法返回的值，因此您需要覆盖ToString()类中的值以返回所需的{{1} }}

RootObject

无法从object转换为int

1 个答案: