无法在mapbox中加载MultiLineString geojson

Question

我正在使用mapbox的教程，我可以让geojson文件显示得很好。但是当我尝试使用MultiLine geojson时，我一直得到这个异常，它没有显示在我的地图上。

 Exception Loading GeoJSON: org.json.JSONException: Value [-84.38482011299999,44.24712923700008,0] at 1 of type org.json.JSONArray cannot be converted to double

我试着改变了这句话：

  if (!TextUtils.isEmpty(type) && type.equalsIgnoreCase("LineString")) {

我将"LineString“改为"MultiLineString”，但仍然得到了相同的例外。我的代码中的其他内容和现在的教程是一样的。

我目前使用osmdroid，在那里加载geojson没有问题，所以我不认为这是我的文件的问题。

试图切换到mapbox。

 public class MainActivity extends Activity implements OnMapReadyCallback
 {
     private static final String TAG = "DrawGeojsonLineActivity";

private MapView mapView;
private MapboxMap mapboxMap;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    // Mapbox access token is configured here. This needs to be called either in your application
    // object or in the same activity which contains the mapview.
    Mapbox.getInstance(this, "pk.eyJ1IjoiamViMTkyMDA0IiwiYSI6ImNpbWNyODZyaDAwMmZ1MWx2dHdzcHQ5M2EifQ.IZsMnB3wOYFIaX1A5sy7Mw");

    // This contains the MapView in XML and needs to be called after the access token is configured.
    setContentView(R.layout.main);

    mapView = (MapView) findViewById(R.id.mapView);
    mapView.onCreate(savedInstanceState);
    mapView.getMapAsync(this);
}

@Override
public void onMapReady(MapboxMap mapboxMap) {
    this.mapboxMap = mapboxMap;

    // Load and Draw the GeoJSON
    new DrawGeoJson().execute();
}

@Override
public void onResume() {
    super.onResume();
    mapView.onResume();
}

@Override
protected void onStart() {
    super.onStart();
    mapView.onStart();
}

@Override
protected void onStop() {
    super.onStop();
    mapView.onStop();
}

@Override
public void onPause() {
    super.onPause();
    mapView.onPause();
}

@Override
public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    mapView.onSaveInstanceState(outState);
}

@Override
public void onLowMemory() {
    super.onLowMemory();
    mapView.onLowMemory();
}

@Override
public void onDestroy() {
    super.onDestroy();
    mapView.onDestroy();
}

private class DrawGeoJson extends AsyncTask<Void, Void, List<LatLng>> {
    @Override
    protected List<LatLng> doInBackground(Void... voids) {

        List<LatLng> points = new ArrayList<>();

        try {
            // Load GeoJSON file
            InputStream inputStream = getAssets().open("st_helen_trail.geojson");
            BufferedReader rd = new BufferedReader(new InputStreamReader(inputStream, Charset.forName("UTF-8")));
            StringBuilder sb = new StringBuilder();
            int cp;
            while ((cp = rd.read()) != -1) {
                sb.append((char) cp);
            }

            inputStream.close();

            // Parse JSON
            JSONObject json = new JSONObject(sb.toString());
            JSONArray features = json.getJSONArray("features");
            JSONObject feature = features.getJSONObject(0);
            JSONObject geometry = feature.getJSONObject("geometry");
            if (geometry != null) {
                String type = geometry.getString("type");

                // Our GeoJSON only has one feature: a line string
                if (!TextUtils.isEmpty(type) && type.equalsIgnoreCase("MultiLineString")) {

                    // Get the Coordinates
                    JSONArray coords = geometry.getJSONArray("coordinates");
                    for (int lc = 0; lc < coords.length(); lc++) {
                        JSONArray coord = coords.getJSONArray(lc);
                        LatLng latLng = new LatLng(coord.getDouble(1), coord.getDouble(0));
                        points.add(latLng);
                    }
                }
            }
        } catch (Exception exception) {
            Log.e(TAG, "Exception Loading GeoJSON: " + exception.toString());
        }

        return points;
    }

    @Override
    protected void onPostExecute(List<LatLng> points) {
        super.onPostExecute(points);

        if (points.size() > 0) {

            // Draw polyline on map
            mapboxMap.addPolyline(new PolylineOptions()
                                  .addAll(points)
                                  .color(Color.parseColor("#3bb2d0"))
                                  .width(2));
        }
    }
}

}

Answer 1

我大概一周前就想出来了。这就是我要做的

我把这个去掉了：

 new DrawGeoJson().execute();

这是：

 private class DrawGeoJson extends AsyncTask<Void, Void, List<LatLng>> { @Override protected List<LatLng> doInBackground(Void... voids) { List<LatLng> points = new ArrayList<>(); try { // Load GeoJSON file InputStream inputStream = getAssets().open("st_helen_trail.geojson"); BufferedReader rd = new BufferedReader(new InputStreamReader(inputStream, Charset.forName("UTF-8"))); StringBuilder sb = new StringBuilder(); int cp; while ((cp = rd.read()) != -1) { sb.append((char) cp); } inputStream.close(); // Parse JSON JSONObject json = new JSONObject(sb.toString()); JSONArray features = json.getJSONArray("features"); JSONObject feature = features.getJSONObject(0); JSONObject geometry = feature.getJSONObject("geometry"); if (geometry != null) { String type = geometry.getString("type"); // Our GeoJSON only has one feature: a line string if (!TextUtils.isEmpty(type) && type.equalsIgnoreCase("MultiLineString")) { // Get the Coordinates JSONArray coords = geometry.getJSONArray("coordinates"); for (int lc = 0; lc < coords.length(); lc++) { JSONArray coord = coords.getJSONArray(lc); LatLng latLng = new LatLng(coord.getDouble(1), coord.getDouble(0)); points.add(latLng); } } } } catch (Exception exception) { Log.e(TAG, "Exception Loading GeoJSON: " + exception.toString()); } return points; } @Override protected void onPostExecute(List<LatLng> points) { super.onPostExecute(points); if (points.size() > 0) { // Draw polyline on map mapboxMap.addPolyline(new PolylineOptions() .addAll(points) .color(Color.parseColor("#3bb2d0")) .width(2)); } }

然后在"onMapReady“中添加下面的代码

 final AssetManager assetManager = getAssets();
                try {

                    String[] imgPath = assetManager.list("mi_atv");
                    for (int i = 0; i< imgPath.length; i++) {
                        InputStream is1 = assetManager.open("mi_atv/" + imgPath[i]);
                        Log.d(TAG, imgPath[i]);
                        int size = is1.available();
                        byte[] buffer = new byte[size];
                        is1.read(buffer);
                        is1.close();

                        String json1 = new String(buffer, "UTF-8");

                        GeoJsonSource source = new GeoJsonSource(imgPath[i], json1);
                        map.addSource(source);

                        atv = new LineLayer(imgPath[i], imgPath[i]);
                        atv.setProperties(
                            lineColor(Color.parseColor("#7fff00")),

                            lineWidth(1.0f)
                        );
                    map.addLayer(main.atv);
                    }
                }
                 catch (Exception exception) {
                    Log.e(TAG, "Exception Loading GeoJSON: " + exception.toString());
                }

Answer 2

在onPostExecute()方法中添加此代码。

@Override
    protected void onPostExecute(List<LatLng> points) {
        super.onPostExecute(points);

        if (points.size() > 0) {
      LatLng[] dataOfArray = points.toArray(new LatLng[points.size()]);
            // Draw polyline on map
            mapboxMap.addPolyline(new PolylineOptions()
                                  .addAll(dataOfArray)
                                  .color(Color.parseColor("#3bb2d0"))
                                  .width(2));
        }
    }

Answer 3

问题是，在多行字符串的情况下，您需要获得一个额外的数组。

多个例子：

坐标：[ 7.38588715，44.17675579，7.385923192，44.176754868，.

LINESTRING示例：

坐标：[ 7.38588715，44.17675579，7.385923192，44.176754868，.

因此：

//replace linestring with multilinestring:
if (!TextUtils.isEmpty(type) && type.equalsIgnoreCase("MultiLineString")) {
    // get extra array adding .getJSONArray(0)
    JSONArray coords = geometry.getJSONArray("coordinates").getJSONArray(0);
    for (int lc = 0; lc < coords.length(); lc++) {