Question

我从这个网址中获取了一些仅用于测试的点数：

https://maps.googleapis.com/maps/api/directions/json?origin=29.6628166, 52.4230969&destination=27.1908698,56.1678579&key=mykey

我运行这个AsyncTask类以获取和绘制方向，这个类在Map类中用于扩展AppCompatActivity：

private class direction extends AsyncTask<String, Void, String> {
    private Context mContext;
    List<LatLng> pontos;
    ProgressDialog dialog;
    double currentLatitude, currentLongitude,destinationLatitude,destinationLongitude;
    String walkDistance;

    public direction (Context context,LatLng point){
        mContext = context;
        destinationLatitude = point.latitude;
        destinationLongitude = point.longitude;
    }


    @Override
    protected String doInBackground(String... params) {
        JSONObject obj;


        String response = HttpRequest.get("https://maps.googleapis.com/maps/api/directions/json?origin=29.6628166, 52.4230969&destination=27.1908698,56.1678579&key=mykey").body();


        try {
            System.out.println("Response content 1 was " + response);

            String jsonOutput = response.toString();

            JSONObject jsonObject = new JSONObject(jsonOutput);

            // routesArray contains ALL routes
            JSONArray routesArray = jsonObject.getJSONArray("routes");
            // Grab the first route
            JSONObject route = routesArray.getJSONObject(0);

            JSONArray legs = route.getJSONArray("legs");
            JSONObject firtsLegs = legs.getJSONObject(0);

            JSONObject distance = firtsLegs.getJSONObject("distance");


            System.out.println("Response test was : " + distance.getString("text"));

            walkDistance = distance.getString("text");

            //Toast.makeText(getApplicationContext(), "فاصله شما تا نقطه: " + distance.getString("text"), Toast.LENGTH_LONG).show();


            JSONObject poly = route.getJSONObject("overview_polyline");
            String polyline = poly.getString("points");
            pontos = decodePoly(polyline);


            return response;

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return "";

    }

    @Override
    protected void onPostExecute(String result) {

        Toast.makeText(getApplicationContext(), "distance : "+walkDistance, Toast.LENGTH_LONG).show();

        /*System.out.println("Response content 2 was " + result);
        Polygon polygon = mapFragment.addPolygon(new PolygonOptions()
        .add(new LatLng(35.7513974, 51.4350038),
             new LatLng(35.7713974, 51.4350038),
             new LatLng(35.7913974, 51.4350038),
             new LatLng(35.7913974, 51.5350038))
        .strokeWidth(5)
        .strokeColor(Color.BLUE));*/


        for (int i = 0; i < pontos.size() - 1; i++) {
            LatLng src = pontos.get(i);
            LatLng dest = pontos.get(i + 1);
            try{
                //here is where it will draw the polyline in your map
                /*Polyline line = googleMap.addPolyline(new PolylineOptions()
                        .add(new LatLng(src.latitude, src.longitude),
                                new LatLng(dest.latitude,                dest.longitude))
                        .width(10).color(Color.BLUE).geodesic(false));

                */

                Polygon line = googleMap.addPolygon(new PolygonOptions()
                        .add(new LatLng(src.latitude, src.longitude),
                                new LatLng(dest.latitude,                dest.longitude))
                        .strokeColor(Color.BLUE).geodesic(true));



            }catch(NullPointerException e){
                Log.e("Error", "NullPointerException onPostExecute: " + e.toString());
            }catch (Exception e2) {
                Log.e("Error", "Exception onPostExecute: " + e2.toString());
            }

        }

        dialog.dismiss();
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        dialog = new ProgressDialog(Map.this);
        dialog.setMessage("در حال مشخص کردن مسیر شما هستیم، لطفا صبر کنید.");
        dialog.setIndeterminate(false);
        dialog.setCancelable(false);
        dialog.show();


        /*gps = new GPSTracker(Map.this);

        // Check if GPS enabled
        if(gps.canGetLocation()) {

            currentLatitude = gps.getLatitude();
            currentLongitude = gps.getLongitude();

            // \n is for new line
            Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + currentLatitude + "\nLong: " + currentLongitude, Toast.LENGTH_LONG).show();
        } else {
            // Can't get location.
            // GPS or network is not enabled.
            // Ask user to enable GPS/network in settings.
            gps.showSettingsAlert();
        }*/





    }

    @Override
    protected void onProgressUpdate(Void... values) {}
}

但路线不在路上，它看起来像波纹管图像：

Answer 1

您正在使用返回的overview_polyline对象中的routes来绘制路径。正如the documentation所说（强调我的）

overview_polyline包含一个单点对象，该对象包含路径的编码折线表示。 此折线是生成路线的近似（平滑）路径。

如果您绘制polyline数组中收到的每个step的{{1}}对象，您将得到更好的近似值。

在您的示例中（红线表示legs，蓝线表示收到的第一个overview_polyline的{{1}}对象：

地图v2绘制的折线不完全在路上

1 个答案: