Google maps api v2获取路线

Question

我在android中使用google maps api v2。我已经放置了一个标记。我如何获得当前位置和标记之间的方向。任何帮助都很棒。

Answer 1

看看这个代码，我在这里提供的职位之一来自谷歌的方向API创建折线，你可以改变，如果你想从其他来源获得它是获取数据的类，但你这是怎么做到这一点。创建一个类，将负责获取方向和解析：

public class GMapV2Direction { 
public final static String MODE_DRIVING = "driving"; 
public final static String MODE_WALKING = "walking"; 

public GMapV2Direction() { } 

public Document getDocument(LatLng start, LatLng end, String mode) { 
    String url = "http://maps.googleapis.com/maps/api/directions/xml?" 
      + "origin=" + start.latitude + "," + start.longitude 
      + "&destination=" + end.latitude + "," + end.longitude 
      + "&sensor=false&units=metric&mode="+ mode; 

    try { 
     HttpClient httpClient = new DefaultHttpClient(); 
     HttpContext localContext = new BasicHttpContext(); 
     HttpPost httpPost = new HttpPost(url); 
     HttpResponse response = httpClient.execute(httpPost, localContext); 
     InputStream in = response.getEntity().getContent(); 
     DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder(); 
     Document doc = builder.parse(in); 
     return doc; 
    } catch (Exception e) { 
     e.printStackTrace(); 
    } 
    return null; 
} 

public String getDurationText (Document doc) { 
    NodeList nl1 = doc.getElementsByTagName("duration"); 
    Node node1 = nl1.item(0); 
    NodeList nl2 = node1.getChildNodes(); 
    Node node2 = nl2.item(getNodeIndex(nl2, "text")); 
    Log.i("DurationText", node2.getTextContent()); 
    return node2.getTextContent(); 
} 

public int getDurationValue (Document doc) { 
    NodeList nl1 = doc.getElementsByTagName("duration"); 
    Node node1 = nl1.item(0); 
    NodeList nl2 = node1.getChildNodes(); 
    Node node2 = nl2.item(getNodeIndex(nl2, "value")); 
    Log.i("DurationValue", node2.getTextContent()); 
    return Integer.parseInt(node2.getTextContent()); 
} 

public String getDistanceText (Document doc) { 
    NodeList nl1 = doc.getElementsByTagName("distance"); 
    Node node1 = nl1.item(0); 
    NodeList nl2 = node1.getChildNodes(); 
    Node node2 = nl2.item(getNodeIndex(nl2, "text")); 
    Log.i("DistanceText", node2.getTextContent()); 
    return node2.getTextContent(); 
} 

public int getDistanceValue (Document doc) { 
    NodeList nl1 = doc.getElementsByTagName("distance"); 
    Node node1 = nl1.item(0); 
    NodeList nl2 = node1.getChildNodes(); 
    Node node2 = nl2.item(getNodeIndex(nl2, "value")); 
    Log.i("DistanceValue", node2.getTextContent()); 
    return Integer.parseInt(node2.getTextContent()); 
} 

public String getStartAddress (Document doc) { 
    NodeList nl1 = doc.getElementsByTagName("start_address"); 
    Node node1 = nl1.item(0); 
    Log.i("StartAddress", node1.getTextContent()); 
    return node1.getTextContent(); 
} 

public String getEndAddress (Document doc) { 
    NodeList nl1 = doc.getElementsByTagName("end_address"); 
    Node node1 = nl1.item(0); 
    Log.i("StartAddress", node1.getTextContent()); 
    return node1.getTextContent(); 
} 

public String getCopyRights (Document doc) { 
    NodeList nl1 = doc.getElementsByTagName("copyrights"); 
    Node node1 = nl1.item(0); 
    Log.i("CopyRights", node1.getTextContent()); 
    return node1.getTextContent(); 
} 

public ArrayList<LatLng> getDirection (Document doc) { 
    NodeList nl1, nl2, nl3; 
    ArrayList<LatLng> listGeopoints = new ArrayList<LatLng>(); 
    nl1 = doc.getElementsByTagName("step"); 
    if (nl1.getLength() > 0) { 
     for (int i = 0; i < nl1.getLength(); i++) { 
      Node node1 = nl1.item(i); 
      nl2 = node1.getChildNodes(); 

      Node locationNode = nl2.item(getNodeIndex(nl2, "start_location")); 
      nl3 = locationNode.getChildNodes(); 
      Node latNode = nl3.item(getNodeIndex(nl3, "lat")); 
      double lat = Double.parseDouble(latNode.getTextContent()); 
      Node lngNode = nl3.item(getNodeIndex(nl3, "lng")); 
      double lng = Double.parseDouble(lngNode.getTextContent()); 
      listGeopoints.add(new LatLng(lat, lng)); 

      locationNode = nl2.item(getNodeIndex(nl2, "polyline")); 
      nl3 = locationNode.getChildNodes(); 
      latNode = nl3.item(getNodeIndex(nl3, "points")); 
      ArrayList<LatLng> arr = decodePoly(latNode.getTextContent()); 
      for(int j = 0 ; j < arr.size() ; j++) { 
       listGeopoints.add(new LatLng(arr.get(j).latitude, arr.get(j).longitude)); 
      } 

      locationNode = nl2.item(getNodeIndex(nl2, "end_location")); 
      nl3 = locationNode.getChildNodes(); 
      latNode = nl3.item(getNodeIndex(nl3, "lat")); 
      lat = Double.parseDouble(latNode.getTextContent()); 
      lngNode = nl3.item(getNodeIndex(nl3, "lng")); 
      lng = Double.parseDouble(lngNode.getTextContent()); 
      listGeopoints.add(new LatLng(lat, lng)); 
     } 
    } 

    return listGeopoints; 
} 

private int getNodeIndex(NodeList nl, String nodename) { 
    for(int i = 0 ; i < nl.getLength() ; i++) { 
     if(nl.item(i).getNodeName().equals(nodename)) 
      return i; 
    } 
    return -1; 
} 

private ArrayList<LatLng> decodePoly(String encoded) { 
    ArrayList<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 position = new LatLng((double) lat/1E5, (double) lng/1E5); 
     poly.add(position); 
    } 
    return poly; 
} 
} 

创建getDirections AsyncTask：

public class GetDirectionsAsyncTask extends AsyncTask<Map<String, String>, Object, ArrayList<LatLng>> { 

public static final String USER_CURRENT_LAT = "user_current_lat"; 
public static final String USER_CURRENT_LONG = "user_current_long"; 
public static final String DESTINATION_LAT = "destination_lat"; 
public static final String DESTINATION_LONG = "destination_long"; 
public static final String DIRECTIONS_MODE = "directions_mode"; 
private MapFragmentActivity activity; 
private String url; 

private Exception exception; 

private Dialog progressDialog; 

public GetDirectionsAsyncTask(MapFragmentActivity activity /*String url*/) 
{ 
    super(); 
    this.activity = activity; 

    // this.url = url; 
} 

public void onPreExecute() { 
    progressDialog = DialogUtils.createProgressDialog(activity, activity.getString(R.string.get_data_dialog_message)); 
    progressDialog.show(); 
} 

@Override 
public void onPostExecute(ArrayList<LatLng> result) { 
    progressDialog.dismiss(); 

    if (exception == null) { 
     activity.handleGetDirectionsResult(result); 
    } else { 
     processException(); 
    } 
} 

@Override 
protected ArrayList<LatLng> doInBackground(Map<String, String>... params) { 

    Map<String, String> paramMap = params[0]; 
    try{ 
     LatLng fromPosition = new LatLng(Double.valueOf(paramMap.get(USER_CURRENT_LAT)) , Double.valueOf(paramMap.get(USER_CURRENT_LONG))); 
     LatLng toPosition = new LatLng(Double.valueOf(paramMap.get(DESTINATION_LAT)) , Double.valueOf(paramMap.get(DESTINATION_LONG))); 
     GMapV2Direction md = new GMapV2Direction(); 
     Document doc = md.getDocument(fromPosition, toPosition, paramMap.get(DIRECTIONS_MODE)); 
     ArrayList<LatLng> directionPoints = md.getDirection(doc); 
     return directionPoints; 

    } 
    catch (Exception e) { 
     exception = e; 
     return null; 
    } 
} 

private void processException() { 
    Toast.makeText(activity, activity.getString(R.string.error_when_retrieving_data), 3000).show(); 
} 

} 

在你Activity创建这些2种方法：

public void handleGetDirectionsResult(ArrayList<LatLng> directionPoints) 
{ 
    Polyline newPolyline; 
    GoogleMap mMap = ((SupportMapFragment)getSupportFragmentManager().findFragmentById(R.id.map)).getMap(); 
    PolylineOptions rectLine = new PolylineOptions().width(3).color(Color.RED); 

    for(int i = 0 ; i < directionPoints.size() ; i++) 
    {   
     rectLine.add(directionPoints.get(i)); 
    } 
    newPolyline = mMap.addPolyline(rectLine); 
} 


public void findDirections(double fromPositionDoubleLat, double fromPositionDoubleLong, double toPositionDoubleLat, double toPositionDoubleLong, String mode) 
{ 
    Map<String, String> map = new HashMap<String, String>(); 
    map.put(GetDirectionsAsyncTask.USER_CURRENT_LAT, String.valueOf(fromPositionDoubleLat)); 
    map.put(GetDirectionsAsyncTask.USER_CURRENT_LONG, String.valueOf(fromPositionDoubleLong)); 
    map.put(GetDirectionsAsyncTask.DESTINATION_LAT, String.valueOf(toPositionDoubleLat)); 
    map.put(GetDirectionsAsyncTask.DESTINATION_LONG, String.valueOf(toPositionDoubleLong)); 
    map.put(GetDirectionsAsyncTask.DIRECTIONS_MODE, mode); 

    GetDirectionsAsyncTask asyncTask = new GetDirectionsAsyncTask(this); 
    asyncTask.execute(map); 
} 

最后运行这种方法来创建Polyline：

findDirections(AppObj.getInstance().currentUserLocation.getLatitude(), 
                AppObj.getInstance().currentUserLocation.getLongitude(), 
                clickMarkerLatLng.latitude, clickMarkerLatLng.longitude, GMapV2Direction.MODE_DRIVING);