Xamarin.Android 入门实例（1）之获取与解析JSON

1.Main.axml 视图界面

2.视图代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:minWidth="25px"
    android:minHeight="25px">
    <ListView
        android:id="@android:id/list"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />
</LinearLayout>

3.MainActivity.cs

using System;
using System.Net;
using System.IO;
using System.Json;
using System.Linq;
using System.Xml.Linq;

using Android.App;
using Android.Content;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;

namespace NetJsonList
{
    [Activity(Label = "NetJsonList", MainLauncher = true, Icon = "@drawable/icon")]
    public class MainActivity : ListActivity
    {
        class Test : Java.Lang.Object
        {
            public string[] Results { get; set; }
        }

        Test t;

        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);
            SetContentView(Resource.Layout.Main);
            LoadXamarin();
        }

        //重写该方法
        public override Java.Lang.Object OnRetainNonConfigurationInstance()
        {
            return t;
        }

        public void LoadXamarin()
        {
            t = LastNonConfigurationInstance as Test;
            ////判断是否存在之前的状态
            if (t != null)
            {
                ListAdapter = new ArrayAdapter<string>(this, Resource.Id.listView1, t.Results);
            }
            else
            {

                //JSON请求URL
                string url = "http://192.168.1.2/Country/OaAreaByCountryId?countryId=21&pid=76";
                /*
                 {"stats":1,"result":[{"pid":76,"id":77,"name":"丽水市","py":"L","items":[{"iskc":true,"ids":"","peisongurl":"","id":78,"name":"莲都区","py":"L"},{"iskc":true,"ids":"","peisongurl":"","id":79,"name":"龙泉市","py":"L"},{"iskc":true,"ids":"","peisongurl":"","id":80,"name":"青田县","py":"Q"},{"iskc":true,"ids":"","peisongurl":"","id":81,"name":"缙云县","py":"J"},{"iskc":true,"ids":"","peisongurl":"","id":82,"name":"遂昌县","py":"S"},{"iskc":true,"ids":"","peisongurl":"","id":83,"name":"松阳县","py":"S"},{"iskc":true,"ids":"","peisongurl":"","id":84,"name":"云和县","py":"Y"},{"iskc":true,"ids":"","peisongurl":"","id":85,"name":"庆元县","py":"Q"},{"iskc":true,"ids":"","peisongurl":"","id":241,"name":"景宁畲族自治县","py":"J"}]}]}
                 */
                //创建一个请求
                var httpReq = (HttpWebRequest)HttpWebRequest.Create(new Uri(url));
                //获取响应
                // var httpRes = (HttpWebResponse)httpReq.GetResponse();
                //读取流文本
                //string text = new StreamReader(httpRes.GetResponseStream()).ReadToEnd();
                //将流中的基于文本的 JSON 反序列化为 JSON CLR 类型
                //var text = (JsonObject)JsonObject.Load(httpRes.GetResponseStream());
                //测试
                //var result = new string[] { "1", "2", "3", "4" };
                //返回包含 JsonObject 中的键的集合
                //var result = text.Keys.ToList();
                //适配列表 视图ListView控件id="@android:id/list"
                //ListAdapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleListItem1, result);

                httpReq.BeginGetResponse(new AsyncCallback(ReadXamarin), httpReq);
            }
        }

        //异步回调方法
        public void ReadXamarin(IAsyncResult asyn)
        {
            var httpReq = (HttpWebRequest)asyn.AsyncState;

            //获取响应
            using (var httpRes = (HttpWebResponse)httpReq.EndGetResponse(asyn))
            {
                //判断是否成功获取响应
                if (httpRes.StatusCode == HttpStatusCode.OK)
                {
                    //读取响应
                    //var text = new StreamReader(httpRes.GetResponseStream()).ReadToEnd();
                    var text = (JsonObject)JsonObject.Load(httpRes.GetResponseStream());
                    //返回包含 JsonObject 中的键的集合
                    var result = text.Keys.ToList();
                    //适配列表 视图ListView控件id="@android:id/list"
                    //ListAdapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleListItem1, result);
                    //切换到UI线程，否则无法对控件进行操作
                    RunOnUiThread(() =>
                    {
                        ListAdapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleListItem1, result);
                    });
                }
            }
        }
    }
}

运行效果

源码下载：NetJsonList.zip