如何在纬度和经度的帮助下在谷歌地图上绘制路线

Question

我想在经度和纬度的帮助下在谷歌地图上显示路线方向。我已经尝试了一些代码，但它在方向 API 中给了我一条错误消息

此 API 项目无权使用此 API。

我无法使用免费试用版启用方向 API

我的代码片段

public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;
    int permission = ContextCompat.checkSelfPermission(this,
            Manifest.permission.ACCESS_FINE_LOCATION);
    if (permission == PackageManager.PERMISSION_GRANTED) {
        //mMap.setMyLocationEnabled(true);
        // Add a marker in Sydney and move the camera
        //LatLng sydney = new LatLng(lat, lon);
        LatLng sydney = new LatLng(lat, lon);
        mMap.addMarker(new MarkerOptions().position(sydney).title("Current Location"));
        mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
        // mMap.setMyLocationEnabled(true);
    } else {
        requestPermission(
                Manifest.permission.ACCESS_FINE_LOCATION,
                LOCATION_REQUEST_CODE);
    }

    mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
        @Override
        public void onMapClick(LatLng latLng) {
            if (markerPoints.size() > 1) {
                markerPoints.clear();
                mMap.clear();
            }
            // Adding new item to the ArrayList
            markerPoints.add(latLng);
            // Creating MarkerOptions
            MarkerOptions options = new MarkerOptions();
            // Setting the position of the marker
            options.position(latLng);
            if (markerPoints.size() == 1) {
                options.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN));
            } else if (markerPoints.size() == 2) {
                options.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED));
            }
            // Add new marker to the Google Map Android API V2
            mMap.addMarker(options);
            // Checks, whether start and end locations are captured
            if (markerPoints.size() >= 2) {
                LatLng origin = (LatLng) markerPoints.get(0);
                LatLng dest = (LatLng) markerPoints.get(1);
                // Getting URL to the Google Directions API
                String url = getDirectionsUrl(origin, dest);
                DownloadTask downloadTask = new DownloadTask();
                // Start downloading json data from Google Directions API
                downloadTask.execute(url);
            }
        }
    });


}

---

private class DownloadTask extends AsyncTask<String, Void, String> {
    @Override
    protected String doInBackground(String... url) {
        String data = "";
        try {
            data = downloadUrl(url[0]);
        } catch (Exception e) {
            Log.d("Background Task", e.toString());
        }
        return data;
    }
    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);
        ParserTask parserTask = new ParserTask();

        parserTask.execute(result);
    }
}

---

private class ParserTask extends AsyncTask<String, Integer, List<List<HashMap<String, String>>>> {
    // Parsing the data in non-ui thread
    @Override
    protected List<List<HashMap<String, String>>> doInBackground(String... jsonData) {
        JSONObject jObject;
        List<List<HashMap<String, String>>> routes = null;
        try {
            jObject = new JSONObject(jsonData[0]);
            DirectionsJSONParser parser = new DirectionsJSONParser();
            routes = parser.parse(jObject);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return routes;
    }
    @Override
    protected void onPostExecute(List<List<HashMap<String, String>>> result) {
        ArrayList<LatLng> points = new ArrayList<LatLng>();;
        PolylineOptions lineOptions = new PolylineOptions();;
        lineOptions.width(2);
        lineOptions.color(Color.RED);
        MarkerOptions markerOptions = new MarkerOptions();
        // Traversing through all the routes
        for(int i=0;i<result.size();i++){
            // Fetching i-th route
            List<HashMap<String, String>> path = result.get(i);
            // Fetching all the points in i-th route
            for(int j=0;j<path.size();j++){
                HashMap<String,String> point = path.get(j);
                double lat = Double.parseDouble(point.get("lat"));
                double lng = Double.parseDouble(point.get("lng"));
                LatLng position = new LatLng(lat, lng);
                points.add(position);
            }
            // Adding all the points in the route to LineOptions
            lineOptions.addAll(points);
        }
        // Drawing polyline in the Google Map for the i-th route
        if(points.size()!=0)mMap.addPolyline(lineOptions);//to avoid crash
    }
}

---

private String getDirectionsUrl(LatLng origin, LatLng dest) {
    // Origin of route
    String str_origin = "origin=" + origin.latitude + "," + origin.longitude;
    // Destination of route
    String str_dest = "destination=" + dest.latitude + "," + dest.longitude;
    // Sensor enabled
    String sensor = "sensor=false";
    String mode = "mode=driving";
    String key = "key=" + getResources().getString(R.string.google_maps_key);
    // Building the parameters to the web service
    String parameters = str_origin + "&" + str_dest + "&" + key + "&" + mode;
    // Output format
    String output = "json";
    // Building the url to the web service
    String url = "https://maps.googleapis.com/maps/api/directions/" + output + "?" + parameters;

    return url;
}

---

private String downloadUrl(String strUrl) throws IOException {
    String data = "";
    InputStream iStream = null;
    HttpURLConnection urlConnection = null;
    try {
        URL url = new URL(strUrl);
        urlConnection = (HttpURLConnection) url.openConnection();
        urlConnection.connect();
        iStream = urlConnection.getInputStream();
        BufferedReader br = new BufferedReader(new InputStreamReader(iStream));
        StringBuffer sb = new StringBuffer();
        String line = "";
        while ((line = br.readLine()) != null) {
            sb.append(line);
        }
        data = sb.toString();
        br.close();
    } catch (Exception e) {
        Log.d("Exception", e.toString());
    } finally {
        iStream.close();
        urlConnection.disconnect();
    }
    return data;
}

Answer 1

1. 创建地图和地点搜索关键字后，您可以在谷歌API控制台中启用谷歌地图相关库
2. 早期阶段他们每天提供 1000 次免费配额，但现在一切都只需支付，所以您必须添加您的计费帐户