android - 在两个地址之间绘制路线

Question

我必须在两个地址之间绘制一条路线，这些地址写在两个地方的自动完成片段中。我搜索了它，但大多数代码都是 onclick 事件。我必须根据片段中写入的地址绘制折线。你能给我一个关于如何为此编写代码的总体思路吗？

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {


private GoogleMap mMap;
Context context;
Polyline polyline;
Marker markers;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);
    // Obtain the SupportMapFragment and get notified when the map is ready to be used.
    SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
            .findFragmentById(R.id.map);

    mapFragment.getMapAsync(this);
    PlaceAutocompleteFragment autocompleteFragment = (PlaceAutocompleteFragment)
            getFragmentManager().findFragmentById(R.id.place_autocomplete_fragment);

    autocompleteFragment.setOnPlaceSelectedListener(new PlaceSelectionListener() {
        @Override
        public void onPlaceSelected(Place place) {
            // TODO: Get info about the selected place.
            addMarker(place);

            // Log.i(TAG, "Place: " + place.getName());
            String placeName = place.getName().toString();
        }

        @Override
        public void onError(Status status) {
            // TODO: Handle the error.
            //Log.i(TAG, "An error occurred: " + status);
        }
    });
    final PlaceAutocompleteFragment autocompleteFragments = (PlaceAutocompleteFragment)
            getFragmentManager().findFragmentById(R.id.place_autocomplete_fragments);

    autocompleteFragments.setOnPlaceSelectedListener(new PlaceSelectionListener() {
        @Override
        public void onPlaceSelected(Place place) {
            // TODO: Get info about the selected place.
            addMarker(place);
            // Log.i(TAG, "Place: " + place.getName());
            String placeName = place.getName().toString();
        }

        @Override
        public void onError(Status status) {
            // TODO: Handle the error.
            //Log.i(TAG, "An error occurred: " + status);
        }
    });

}

/**
 * Manipulates the map once available.
 * This callback is triggered when the map is ready to be used.
 * This is where we can add markers or lines, add listeners or move the camera. In this case,
 * we just add a marker near Sydney, Australia.
 * If Google Play services is not installed on the device, the user will be prompted to install
 * it inside the SupportMapFragment. This method will only be triggered once the user has
 * installed Google Play services and returned to the app.
 */
@Override
public void onMapReady(final GoogleMap googleMap) {
    mMap = googleMap;

    // Add a marker in Sydney and move the camera


    //LatLng warora = new LatLng(20.2407, 79.0136);
    //LatLng amravati=new LatLng(20.9374,77.7796);
    /*LatLng nagpur=new LatLng(21.1458,79.0882);

    PolylineOptions polylineOptions=new PolylineOptions().add(warora).add(nagpur).width(5).color(Color.BLUE)
            .geodesic(true);
    googleMap.addPolyline(polylineOptions);
    googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(warora,8));
    mMap.addMarker(new MarkerOptions().position(warora).title("Marker in India"));
    //mMap.addMarker(new MarkerOptions().position(amravati).title("Marker in Pune"));
    mMap.addMarker(new MarkerOptions().position(nagpur).title("Marker in Nagpur"));
    mMap.moveCamera(CameraUpdateFactory.newLatLng(warora));
    */
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        // TODO: Consider calling
        //    ActivityCompat#requestPermissions
        // here to request the missing permissions, and then overriding
        //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
        //                                          int[] grantResults)
        // to handle the case where the user grants the permission. See the documentation
        // for ActivityCompat#requestPermissions for more details.
        return;
    }
    mMap.setMyLocationEnabled(true);

}

public void addMarker(Place p) {
        MarkerOptions markerOptions = new MarkerOptions();
        markerOptions.position(p.getLatLng()).title(p.getName() + "");
        mMap.addMarker(markerOptions);
        mMap.moveCamera(CameraUpdateFactory.newLatLng(p.getLatLng()));
        mMap.animateCamera(CameraUpdateFactory.zoomTo(9));
}

}

在我的代码中，我添加了标记，但两个搜索框都在调用一种方法（addMarker）。我想这就是我无法得到它们之间的折线的原因。我尝试使用相同的代码制作不同的方法，然后添加折线，但它不起作用。

Answer 1

我正在为您提供绘制路径以及获取行驶距离和旅行时间的代码。

创建一个新的 java 文件，即“<strong>DirectionsJSONParser.java”：

public class DirectionsJSONParser {

    /** Receives a JSONObject and returns a list of lists containing 
    latitude and longitude */
    public List<List<HashMap<String,String>>> parse(JSONObject jObject){

        List<List<HashMap<String, String>>> routes = new 
        ArrayList<List<HashMap<String,String>>>() ;
        JSONArray jRoutes = null;
        JSONArray jLegs = null;
        JSONArray jSteps = null;
        JSONObject jDistance = null;
        JSONObject jDuration = null;

        try {

            jRoutes = jObject.getJSONArray("routes");

            /** Traversing all routes */
            for(int i=0;i<jRoutes.length();i++){
                jLegs = ( (JSONObject)jRoutes.get(i)).getJSONArray("legs");

                List<HashMap<String, String>> path = new 
                ArrayList<HashMap<String, String>>();

                /** Traversing all legs */
                for(int j=0;j<jLegs.length();j++){

                    /** Getting distance from the json data */
                    jDistance = ((JSONObject) 
                    jLegs.get(j)).getJSONObject("distance");
                    HashMap<String, String> hmDistance = new HashMap<String, 
                    String>();
                    hmDistance.put("distance", jDistance.getString("text"));

                    /** Getting duration from the json data */
                    jDuration = ((JSONObject) 
                    jLegs.get(j)).getJSONObject("duration");
                    HashMap<String, String> hmDuration = new HashMap<String, 
                    String>();
                    hmDuration.put("duration", jDuration.getString("text"));

                    /** Adding distance object to the path */
                    path.add(hmDistance);

                    /** Adding duration object to the path */
                    path.add(hmDuration);

                    jSteps = ( 
                    (JSONObject)jLegs.get(j)).getJSONArray("steps");

                    /** Traversing all steps */
                    for(int k=0;k<jSteps.length();k++){
                        String polyline = "";
                        polyline = (String)((JSONObject)
                        ((JSONObject)jSteps.get(k)).get("polyline"))
                        .get("points");
                        List<LatLng> list = decodePoly(polyline);

                        /** Traversing all points */
                        for(int l=0;l<list.size();l++){
                            HashMap<String, String> hm = new HashMap<String, 
                            String>();
                            hm.put("lat", 
                            Double.toString(((LatLng)list.get(l))
                            .latitude) );
                            hm.put("lng", 
                            Double.toString(((LatLng)list.get(l))
                            .longitude) );
                            path.add(hm);
                        }
                    }
                }
                routes.add(path);
            }
        } catch (JSONException e) {
           e.printStackTrace();
        }catch (Exception e){
        }
        return routes;
    }

    /**
    * Method to decode polyline points
    * Courtesy : jeffreysambells.com/2010/05/27/decoding-polylines-from-
    google-maps-direction-api-with-java
    * */
    private List<LatLng> decodePoly(String encoded) {

        List<LatLng> poly = new ArrayList<LatLng>();
        int index = 0, len = encoded.length();
        int lat = 0, lng = 0;

        while (index < len) {
            int b, shift = 0, result = 0;
            do {
                b = encoded.charAt(index++) - 63;
                result |= (b & 0x1f) << shift;
                shift += 5;
            } while (b >= 0x20);
            int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
            lat += dlat;

            shift = 0;
            result = 0;
            do {
                b = encoded.charAt(index++) - 63;
                result |= (b & 0x1f) << shift;
                shift += 5;
            } while (b >= 0x20);
            int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
            lng += dlng;

            LatLng p = new LatLng((((double) lat / 1E5)),
            (((double) lng / 1E5)));
            poly.add(p);
        }
        return poly;
    }
}

现在在您的地图所在的 MainActivity 中：

public class MainActivity extends FragmentActivity {

    GoogleMap map;
    ArrayList<LatLng> markerPoints;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        // Initializing
        markerPoints = new ArrayList<LatLng>();

        // Getting reference to SupportMapFragment of the activity_main
        SupportMapFragment fm = 
        (SupportMapFragment)getSupportFragmentManager().
        findFragmentById(R.id.map);

        // Getting Map for the SupportMapFragment
        map = fm.getMap();

        // Enable MyLocation Button in the Map
        map.setMyLocationEnabled(true);

        // Setting onclick event listener for the map
        map.setOnMapClickListener(new OnMapClickListener() {

            @Override
            public void onMapClick(LatLng point) {

                // Already two locations
                if(markerPoints.size()>1){
                    markerPoints.clear();
                    map.clear();
                }

                // Adding new item to the ArrayList
                markerPoints.add(point);

                // Creating MarkerOptions
                MarkerOptions options = new MarkerOptions();

                // Setting the position of the marker
                options.position(point);

                /**
                * For the start location, the color of marker is GREEN and
                * for the end location, the color of marker is RED.
                */
                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
                map.addMarker(options);

                // Checks, whether start and end locations are captured
                if(markerPoints.size() >= 2){
                    LatLng origin = markerPoints.get(0);
                    LatLng dest = 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 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";

        // Building the parameters to the web service
        String parameters = str_origin+"&"+str_dest+"&"+sensor;

        // 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;
    }

    /** A method to download json data from url */
    private String downloadUrl(String strUrl) throws IOException{
        String data = "";
        InputStream iStream = null;
        HttpURLConnection urlConnection = null;
        try{
            URL url = new URL(strUrl);

            // Creating an http connection to communicate with url
            urlConnection = (HttpURLConnection) url.openConnection();

            // Connecting to url
            urlConnection.connect();

            // Reading data from url
            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 while downloading url", e.toString());
        }finally{
            iStream.close();
            urlConnection.disconnect();
        }
        return data;
    }

    // Fetches data from url passed
    private class DownloadTask extends AsyncTask<String, Void, String>{

        // Downloading data in non-ui thread
        @Override
        protected String doInBackground(String... url) {

            // For storing data from web service
            String data = "";

            try{
                // Fetching the data from web service
                data = downloadUrl(url[0]);
            }catch(Exception e){
                Log.d("Background Task",e.toString());
            }
            return data;
        }

        // Executes in UI thread, after the execution of
        // doInBackground()
        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);

            ParserTask parserTask = new ParserTask();

            // Invokes the thread for parsing the JSON data
            parserTask.execute(result);
        }
    }

    /** A class to parse the Google Places in JSON format */
    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();

                // Starts parsing data
                routes = parser.parse(jObject);
            }catch(Exception e){
                e.printStackTrace();
            }
            return routes;
        }

        // Executes in UI thread, after the parsing process
        @Override
        protected void onPostExecute(List<List<HashMap<String,
        String>>> result) {
            ArrayList<LatLng> points = null;
            PolylineOptions lineOptions = null;
            MarkerOptions markerOptions = new MarkerOptions();
            String distance = "";
            String duration = "";

            if(result.size()<1){
                Toast.makeText(getBaseContext(), "No Points", 
                Toast.LENGTH_SHORT).show();
                return;
            }

            // Traversing through all the routes
            for(int i=0;i<result.size();i++){
                points = new ArrayList<LatLng>();
                lineOptions = new PolylineOptions();

                // 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);

                    if(j==0){    // Get distance from the list
                        distance = (String)point.get("distance");
                        continue;
                    }else if(j==1){ // Get duration from the list
                        duration = (String)point.get("duration");
                        continue;
                    }

                    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);
                lineOptions.width(2);
                lineOptions.color(Color.RED);
            }

            // Drawing polyline in the Google Map for the i-th route
            map.addPolyline(lineOptions);
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is 
        present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
}

而已！

如果您需要更多解释，这里是链接。

Answer 2

您需要获取两个地址的坐标——谷歌地图有一个 API库可以做到这一点。然后按照指南在此链接上的地图上绘制折线。按照两个链接上的指南进行操作，您应该被分类。希望这可以帮助。

Answer 3

使用google 路线 API获取您的 2 个地址之间的航点。Google 提供了一个 Util 库来帮助您从地图上的响应中显示“overview_polyline”。