将层从 cartoDB 浏览器添加到 Android 应用程序答案

【问题标题】：Add layers from cartoDB browser to Android Application将层从 cartoDB 浏览器添加到 Android 应用程序
【发布时间】：2018-11-06 04:55:53
【问题描述】：

我在 cartoDB 浏览器中有一个包含三层的地图，我无法在 android 应用程序中的地图中添加图层如何使用 java 代码将 CartoDB 浏览器中的 aKMZ 图层（不是底图）添加到 Android 应用程序以显示应用程序中的所有图层?? 谁能帮我？ ????

添加底图的代码

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // Register the license so that CARTO online services can be used
    MapView.registerLicense(LICENSE,getApplicationContext());

    // Get 'mapView' object from the application layout
    mapView = (MapView) this.findViewById(R.id.mapView);

    // Add basemap layer to mapView
    CartoOnlineVectorTileLayer baseLayer = new CartoOnlineVectorTileLayer(CartoBaseMapStyle.CARTO_BASEMAP_STYLE_VOYAGER);
    mapView.getLayers().add(baseLayer);
}

【问题讨论】：

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标签： java android cartodb

【解决方案1】：

我的项目是室内导航系统，所以我需要 cartoDB 地图中的图层来显示 Android App 中的建筑水平

【讨论】：

【解决方案2】：

建议的解决方案是预先使用一些工具将 KMZ 转换为 GeoJSON。 SDK 本身不这样做。在 SDK 中，您可以使用 GeoJSONGeometryReader 来解析 GeoJSON 并最终将其添加到映射为 VectorLayer。我的通用函数来完成这一切：

// usage: the file tpr-men.geojson is in assets folder of project
polygonGeoJSON(mapView,"tpr-men.geojson",android.graphics.Color.LTGRAY);

//helper function to read polygons from GeoJSON file, sets styles

private void polygonGeoJSON(MapView mapView, final String fileName, int color) {

    final Thread thread;// Initialize a local vector data source
    final LocalVectorDataSource source = new LocalVectorDataSource(baseProjection);

    // Initialize a vector layer with the previous data source
    VectorLayer vectorLayer = new VectorLayer(source);

    vectorLayer.setVectorElementEventListener(listener);

    // Add the clustered vector layer to the map
    mapView.getLayers().add(vectorLayer);



    LineStyleBuilder lsb = new LineStyleBuilder();
    lsb.setColor(new Color(color));
    lsb.setWidth(0.5f);
    lsb.setLineJoinType(LineJoinType.LINE_JOIN_TYPE_NONE);
    lsb.setLineEndType(LineEndType.LINE_END_TYPE_NONE);

    PolygonStyleBuilder polygonBuilder = new PolygonStyleBuilder();
    polygonBuilder.setColor(new Color(color & 0xbbffffff)); // a bit transparent
   //polygonBuilder.setLineStyle(lsb.buildStyle());
    final PolygonStyle style = polygonBuilder.buildStyle();

    // As the file to load is rather large, we don't want to block our main thread
    thread = new Thread(new Runnable() {
        @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
        @Override
        public void run() {


            try {

                // Read GeoJSON, parse it using SDK GeoJSON parser
                GeoJSONGeometryReader reader = new GeoJSONGeometryReader();

                // Set target projection to base (mercator)
                reader.setTargetProjection(baseProjection);
                Log.d("log","Starting load from .geojson");

                // Read features from local asset
                String json = loadJSONFromAsset(fileName);
                Log.d("log","Finished load from .geojson");

                FeatureCollection features = reader.readFeatureCollection(json);
                Log.d("log","Finished parsing of geojson, loaded objects: "+features.getFeatureCount());

                source.addFeatureCollection(features,style);

            } catch (IOException e) {
                e.printStackTrace();
            }

            Log.d("log","Finished load from geojson");

        }
    });

    thread.start();


}

// general helper function to read file to String
private String loadJSONFromAsset(String fileName) throws IOException {

    InputStream is = getAssets().open(fileName);
    int size = is.available();
    byte[] buffer = new byte[size];
    is.read(buffer);
    is.close();

    return new String(buffer, "UTF-8");

}

【讨论】：