AMap行政区查询服务

AMap.DistrictSearch行政区查询服务插件，提供全国各省、市、县、区的中心点经纬度、行政区边界坐标组、下级行政区等信息。根据行政区边界坐标组可在地图上绘制行政区边界。（本文为原创，并在项目中验证成功。作者：张甫军）

第一步，插件及样式的引用：

    <link rel="stylesheet" href="http://cache.amap.com/lbs/static/main1119.css" />
    <script src="http://webapi.amap.com/maps?v=1.3&key=7defcebd378d7fcd05dbcb9298d20d2e&plugin=AMap.PolyEditor,AMap.CircleEditor,AMap.MouseTool,AMap.DistrictSearch"></script>
    <script type="text/javascript" src="http://cache.amap.com/lbs/static/addToolbar.js"></script>
 <script type="text/javascript" src="http://webapi.amap.com/demos/js/liteToolbar.js"></script>

第二步，HTML代码：

  <div id="container"></div>
    <div id="tip">
        省：<select id='province' style="100px" onchange='search(this)'></select>
        市：<select id='city' style="100px" onchange='search(this)'></select>
        区：<select id='district' style="100px" onchange='search(this)'></select>
        街道：<select id='street' style="100px" onchange='setCenter(this)'></select>
        &nbsp;&nbsp;<input type="button" id="clearMap" onclick="clearMap()" value="清除" />
    </div>

第三步，页面CSS样式：

    <style type="text/css">
        #tip {
            background-color: #fff;
            padding: 0 10px;
            border: 1px solid silver;
            box-shadow: 3px 4px 3px 0px silver;
            position: absolute;
            font-size: 12px;
            right: 10px;
            top: 5px;
            border-radius: 3px;
            line-height: 36px;
        }
    </style>

第四步，JavaScript代码：

1. 初始化地图：

           var editorTool, district, polygons = [], citycode, map = new AMap.Map("container", {
               //resizeEnable: true,
               //center: [116.403322, 39.900255],
               //zoom: 13
               resizeEnable: true,
               //center: [116.30946, 39.937629],
               zoom: 3
           });

2. 初始化搜索下拉框：

           var citySelect = document.getElementById('city');
           var districtSelect = document.getElementById('district');
           var areaSelect = document.getElementById('street');
   
           var opts = {
               subdistrict: 1,
               level: 'city',
               showbiz: false
           };
           district = new AMap.DistrictSearch(opts);
           district.search('中国', function (status, result) {
               if (status == 'complete') {
                   getData(result.districtList[0]);
               }
           });
           var mapCenter = null;
           var districtObj = {
               Center: null,
               Bounds: null
           };
           function getData(data) {
               var bounds = data.boundaries;
               mapCenter = data.center;
               districtObj.Center = data.center;
               districtObj.Bounds = bounds == null ? districtObj.Bounds : bounds;
               console.log('default1');
               if (bounds && '@((int)ElectronicFenceModel.ShapeType.District)' == '@((int)shapeType)') {
                   for (var i = 0, l = bounds.length; i < l; i++) {
                       var polygon = new AMap.Polygon({
                           map: map,
                           strokeWeight: 1,
                           strokeColor: '#CC66CC',
                           fillColor: '#CCF3FF',
                           fillOpacity: 0.5,
                           path: bounds[i]
                       });
                       polygons.push(polygon);
                   }
                   map.setFitView();
               }
   
               var subList = data.districtList;
               var level = data.level;
   
               if (level === 'province') {
                   nextLevel = 'city';
                   citySelect.innerHTML = '';
                   districtSelect.innerHTML = '';
                   areaSelect.innerHTML = '';
               } else if (level === 'city') {
                   nextLevel = 'district';
                   districtSelect.innerHTML = '';
                   areaSelect.innerHTML = '';
               } else if (level === 'district') {
                   nextLevel = 'street';
                   areaSelect.innerHTML = '';
               }
               if (subList) {
                   var contentSub = new Option('--请选择--');
                   for (var i = 0, l = subList.length; i < l; i++) {
                       var name = subList[i].name;
                       var levelSub = subList[i].level;
                       var cityCode = subList[i].citycode;
                       if (i == 0) {
                           document.querySelector('#' + levelSub).add(contentSub);
                       }
                       contentSub = new Option(name);
                       contentSub.setAttribute("value", levelSub);
                       contentSub.center = subList[i].center;
                       contentSub.adcode = subList[i].adcode;
                       document.querySelector('#' + levelSub).add(contentSub);
                   }
               }
   
           }
           function search(obj) {
               //清除地图上所有覆盖物
               for (var i = 0, l = polygons.length; i < l; i++) {
                   polygons[i].setMap(null);
               }
               var option = obj[obj.options.selectedIndex];
               var keyword = option.text; //关键字
               var adcode = option.adcode;
               district.setLevel(option.value); //行政区级别
               district.setExtensions('all');
               //行政区查询
               //按照adcode进行查询可以保证数据返回的唯一性
               district.search(adcode, function (status, result) {
                   if (status === 'complete') {
                       getData(result.districtList[0]);
                       setFence();
                   }
               });
           }
           function setCenter(obj) {
               mapCenter = obj[obj.options.selectedIndex].center;
               map.setCenter(obj[obj.options.selectedIndex].center);
               setFence();
           }
   
           function clearMap() {
               map.clearMap();
           }

   以上代码，可以完成行政区查询，提供全国各省、市、县、区的中心点经纬度、行政区边界坐标组、下级行政区等信息。根据行政区边界坐标组可在地图上绘制行政区边界。注意：AMap.DistrictSearch行政区查询服务插件的初始化有2种方式，第一种：使用插件同步下发功能才能这样直接使用（本文采用此种方式，注意查看插件的引用）；第二种：（查看下面的代码）

   mapObj.plugin('AMap.DistrictSearch', function () {
   					var opts = {
   					subdistrict: 0, //返回下一级行政区
   					extensions: 'all', //返回行政区边界坐标组等具体信息
   					level:'city' //查询行政级别为 市
   				};
   

   　　

mapObj.plugin('AMap.DistrictSearch', function () {

               var opts = {

               subdistrict: 0, //返回下一级行政区

               extensions: 'all', //返回行政区边界坐标组等具体信息

               level:'city'//查询行政级别为市

            };