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