Android GIS开发系列-- 入门季（15） 网络图层加载

一、首先我们来看一个网络图层：

http://services.arcgisonline.com/arcgis/rest/services/World_Street_Map/MapServer，这是全球街道图。加载的代码也很简单：

 private static final String WORLD_STREETS_URL = "http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer";
    private MapView mMapView = null;
    private ArcGISTiledMapServiceLayer mWorldStreetsLayer = null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mMapView = (MapView) findViewById(R.id.map_view);
        mWorldStreetsLayer = new ArcGISTiledMapServiceLayer(WORLD_STREETS_URL);
        mMapView.addLayer(mWorldStreetsLayer);
        mWorldStreetsLayer.setOnStatusChangedListener(new OnStatusChangedListener() {
            @Override
            public void onStatusChanged(Object o, STATUS status) {
                if (status==STATUS.INITIALIZED){
                    Log.i("huang","加载成功");

                }else if(status==STATUS.INITIALIZATION_FAILED||status==STATUS.LAYER_LOADING_FAILED){
                    Log.i("huang","加载失败");
                }
            }
        });
    }

效果图

问：为什么用ArcGISTiledMapServiceLayer 加载而不用其他图层加载呢？

用浏览器打开
http://services.arcgisonline.com/arcgis/rest/services/World_Street_Map/MapServer，可以看到详细信息。
它的子图层只有一个：

下面是坐标信息，注意Single Fused Map Cache: true，支持缓存。
与Tile Info信息，

通过信息说明这是一个TiledLayer,而ArcGISTiledMapServiceLayer是TiledLayer子类的子类，看一下ArcGISTiledMapServiceLayer的介绍
。

点开World Street Map链接，
http://services.arcgisonline.com/arcgis/rest/services/World_Street_Map/MapServer/0，这是它的唯一子图层。真正加载的也是这个图层

Type虽然说是FeatureLayer，但它得用ArcGISFeatureLayer加载。

ArcGISFeatureLayer arcGISFeatureLayer = new ArcGISFeatureLayer(WORLD_STREETS_URL+"/0", ArcGISFeatureLayer.MODE.ONDEMAND);
        SimpleFillSymbol simpleFillSymbol = new SimpleFillSymbol(Color.argb(0,0,0,0),SimpleFillSymbol.STYLE.SOLID);

        mMapView.addLayer(arcGISFeatureLayer);
        arcGISFeatureLayer.setRenderer(new SimpleRenderer(simpleFillSymbol));
        arcGISFeatureLayer.setOnStatusChangedListener(new OnStatusChangedListener() {
            @Override
            public void onStatusChanged(Object o, STATUS status) {
                if (status==STATUS.INITIALIZED){
                    Log.i("huang","加载成功");

                }else if(status==STATUS.INITIALIZATION_FAILED||status==STATUS.LAYER_LOADING_FAILED){
                    Log.i("huang","加载失败");
                }
            }
        });

上面虽然加载成功，但并看不到图层，而且报错：

FeatureSetCallback.onError
com.esri.core.io.EsriServiceException: Requested operation is not supported by this service.
The requested capability is not supported.

仔细再看网络信息， 
 
 
大体上知道为什么报 The requested capability is not supported。也就是不能用这种方法加载，而得用前面的代码加载！！！

ArcGISDynamicMapServiceLayer

服务地址：
http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Specialty/ESRI_StateCityHighway_USA/MapServer，这是美国的高铁图。
用浏览器打开，有三个子图层，Single Fused Map Cache: false！

下面是ArcGISDynamicMapServiceLayer的介绍：

加载代码 ：

 private static final String DYNAMIC_USA_HIGHWAY_URL = "http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Specialty/ESRI_StateCityHighway_USA/MapServer";
    private ArcGISDynamicMapServiceLayer usaHighwayLayer = null;
    private MapView mMapView = null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mMapView = (MapView) findViewById(R.id.map_view);
        usaHighwayLayer = new ArcGISDynamicMapServiceLayer(DYNAMIC_USA_HIGHWAY_URL);
        mMapView.addLayer(usaHighwayLayer);
        usaHighwayLayer.setOnStatusChangedListener(new OnStatusChangedListener() {
            @Override
            public void onStatusChanged(Object o, STATUS status) {
                if (status==STATUS.INITIALIZED){
                    Log.i("huang","加载成功");

                }else if(status==STATUS.INITIALIZATION_FAILED||status==STATUS.LAYER_LOADING_FAILED){
                    Log.i("huang","加载失败");
                }
            }
        });}

效果图

二、ArcGISFeatureLayer加载图层

服务地图
http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Specialty/ESRI_StateCityHighway_USA/MapServer/0，也就是上面服务的子图层。

 ArcGISFeatureLayer arcGISFeatureLayer = new ArcGISFeatureLayer("http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Specialty/ESRI_StateCityHighway_USA/MapServer/0", ArcGISFeatureLayer.MODE.ONDEMAND);
        mMapView.addLayer(arcGISFeatureLayer);
        arcGISFeatureLayer.setRenderer(new SimpleRenderer(new SimpleLineSymbol(Color.argb(250, 52, 17, 255),2)));
        arcGISFeatureLayer.setOnStatusChangedListener(new OnStatusChangedListener() {
            @Override
            public void onStatusChanged(Object o, STATUS status) {
                if (status==STATUS.INITIALIZED){
                    Log.i("huang","加载成功");

                }else if(status==STATUS.INITIALIZATION_FAILED||status==STATUS.LAYER_LOADING_FAILED){
                    Log.i("huang","加载失败");
                }
            }
        });

注意要设置setRenderer，效果

ArcGISFeatureLayer 具有FeatureLayer的一些查询方法，与前面几讲里FeatureLayer查询相似，这里不再讲了。

//查询要素方法
queryIds(Query query, CallbackListener<int[]> callback)
queryFeatures(Query query, CallbackListener<FeatureSet> callback)

在http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Specialty/ESRI_StateCityHighway_USA/MapServer/0，页面底部，

点击Query进入查询要素界面，可直接 查询要素

where 1=1，点击Query(GET)，可得到以下结果集