Xamarin.Android 入门实例（1）之获取与解析JSON

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:orientation="vertical"
 4     android:layout_width="fill_parent"
 5     android:layout_height="fill_parent"
 6     android:minWidth="25px"
 7     android:minHeight="25px">
 8     <ListView
 9         android:id="@android:id/list"
10         android:layout_width="fill_parent"
11         android:layout_height="wrap_content" />
12 </LinearLayout>

  1 using System;
  2 using System.Net;
  3 using System.IO;
  4 using System.Json;
  5 using System.Linq;
  6 using System.Xml.Linq;
  7 
  8 using Android.App;
  9 using Android.Content;
 10 using Android.Runtime;
 11 using Android.Views;
 12 using Android.Widget;
 13 using Android.OS;
 14 
 15 namespace NetJsonList
 16 {
 17     [Activity(Label = "NetJsonList", MainLauncher = true, Icon = "@drawable/icon")]
 18     public class MainActivity : ListActivity
 19     {
 20         class Test : Java.Lang.Object
 21         {
 22             public string[] Results { get; set; }
 23         }
 24 
 25         Test t;
 26 
 27         protected override void OnCreate(Bundle bundle)
 28         {
 29             base.OnCreate(bundle);
 30             SetContentView(Resource.Layout.Main);
 31             LoadXamarin();
 32         }
 33 
 34         //重写该方法
 35         public override Java.Lang.Object OnRetainNonConfigurationInstance()
 36         {
 37             return t;
 38         }
 39 
 40         public void LoadXamarin()
 41         {
 42             t = LastNonConfigurationInstance as Test;
 43             ////判断是否存在之前的状态
 44             if (t != null)
 45             {
 46                 ListAdapter = new ArrayAdapter<string>(this, Resource.Id.listView1, t.Results);
 47             }
 48             else
 49             {
 50 
 51                 //JSON请求URL
 52                 string url = "http://192.168.1.2/Country/OaAreaByCountryId?countryId=21&pid=76";
 53                 /*
 54                  {"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"}]}]}
 55                  */
 56                 //创建一个请求
 57                 var httpReq = (HttpWebRequest)HttpWebRequest.Create(new Uri(url));
 58                 //获取响应
 59                 // var httpRes = (HttpWebResponse)httpReq.GetResponse();
 60                 //读取流文本
 61                 //string text = new StreamReader(httpRes.GetResponseStream()).ReadToEnd();
 62                 //将流中的基于文本的 JSON 反序列化为 JSON CLR 类型
 63                 //var text = (JsonObject)JsonObject.Load(httpRes.GetResponseStream());
 64                 //测试
 65                 //var result = new string[] { "1", "2", "3", "4" };
 66                 //返回包含 JsonObject 中的键的集合
 67                 //var result = text.Keys.ToList();
 68                 //适配列表 视图ListView控件id="@android:id/list"
 69                 //ListAdapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleListItem1, result);
 70 
 71                 httpReq.BeginGetResponse(new AsyncCallback(ReadXamarin), httpReq);
 72             }
 73         }
 74 
 75         //异步回调方法
 76         public void ReadXamarin(IAsyncResult asyn)
 77         {
 78             var httpReq = (HttpWebRequest)asyn.AsyncState;
 79 
 80             //获取响应
 81             using (var httpRes = (HttpWebResponse)httpReq.EndGetResponse(asyn))
 82             {
 83                 //判断是否成功获取响应
 84                 if (httpRes.StatusCode == HttpStatusCode.OK)
 85                 {
 86                     //读取响应
 87                     //var text = new StreamReader(httpRes.GetResponseStream()).ReadToEnd();
 88                     var text = (JsonObject)JsonObject.Load(httpRes.GetResponseStream());
 89                     //返回包含 JsonObject 中的键的集合
 90                     var result = text.Keys.ToList();
 91                     //适配列表 视图ListView控件id="@android:id/list"
 92                     //ListAdapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleListItem1, result);
 93                     //切换到UI线程，否则无法对控件进行操作
 94                     RunOnUiThread(() =>
 95                     {
 96                         ListAdapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleListItem1, result);
 97                     });
 98                 }
 99             }
100         }
101     }
102 }