本文适合 【android ios】下的google Map 开发
Google Mapandroid版和IOS版的SDK都没有集成路径规划的相关API,若要实现,只能通过http链接请求URL,携带起点终点经纬度,得到返回集合,在地图中展示。
Google Directions API :https://developers.google.com/maps/documentation/directions/#Waypoints
Directions Service:https://developers.google.com/maps/documentation/javascript/directions#DirectionsRequests
举个例子:
https://maps.googleapis.com/maps/api/directions/json?origin=39.99709957757345,116.31184045225382&destination=39.949158391497214,116.4154639095068&sensor=false&mode=driving
origin=起点经纬度 destination=终点经纬度
返回的json数据(网页打开):
/**
* 通过起点终点,组合成url
*
* @param origin
* @param dest
* @return
*/
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";
// Travelling Mode
String mode = "mode=driving";
//waypoints,116.32885,40.036675
String waypointLatLng = "waypoints="+"40.036675"+","+"116.32885";
// Building the parameters to the web service
String parameters = str_origin + "&" + str_dest + "&" + sensor + "&"
+ mode+"&"+waypointLatLng;
// Output format
String output = "json";
// Building the url to the web service
String url = "https://maps.googleapis.com/maps/api/directions/"
+ output + "?" + parameters;
System.out.println("getDerectionsURL--->: " + url);
return url;
}
该方法传递了起点,终点的经纬度,然后组合成了网页请求时用到的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();
}
System.out.println("url:" + strUrl + "----> downloadurl:" + data);
return data;
}
// Fetches data from url passed
private class DownloadTask extends AsyncTask {
// 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>>> {
// Parsing the data in non-ui thread
@Override
protected List>> doInBackground(
String... jsonData) {
JSONObject jObject;
List>> routes = null;
try {
jObject = new JSONObject(jsonData[0]);
DirectionsJSONParser parser = new DirectionsJSONParser();
// Starts parsing data
routes = parser.parse(jObject);
System.out.println("do in background:" + routes);
} catch (Exception e) {
e.printStackTrace();
}
return routes;
}
// Executes in UI thread, after the parsing process
@Override
protected void onPostExecute(List>> result) {
ArrayList points = null;
PolylineOptions lineOptions = null;
MarkerOptions markerOptions = new MarkerOptions();
// Traversing through all the routes
for (int i = 0; i < result.size(); i++) {
points = new ArrayList();
lineOptions = new PolylineOptions();
// Fetching i-th route
List> path = result.get(i);
// Fetching all the points in i-th route
for (int j = 0; j < path.size(); j++) {
HashMap 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);
lineOptions.width(3);
// Changing the color polyline according to the mode
lineOptions.color(Color.BLUE);
}
// Drawing polyline in the Google Map for the i-th route
mGoogleMap.addPolyline(lineOptions);
}
}
异步操作,转换得到的 Google Place json数据,然后显示在google map上。
public class DirectionsJSONParser {
/**
* Receives a JSONObject and returns a list of lists containing latitude and
* longitude
*/
public List>> parse(JSONObject jObject) {
List>> routes = new ArrayList>>();
JSONArray jRoutes = null;
JSONArray jLegs = null;
JSONArray jSteps = 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 path = new ArrayList>();
/** Traversing all legs */
for (int j = 0; j < jLegs.length(); j++) {
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 list = decodePoly(polyline);
/** Traversing all points */
for (int l = 0; l < list.size(); l++) {
HashMap hm = new HashMap();
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 decodePoly(String encoded) {
List poly = new ArrayList();
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;
}
}
效果图
红色的线为驾车线路
蓝色的线为步行线路