答案 0 :(得分：2)
我认为你可以做这样的事情
LatLng origin = sourcePosition;
LatLng dest = destPosition;
DownloadTask1 downloadTask = new DownloadTask1();
String url = downloadTask.getDirectionsUrl1(origin, dest);
downloadTask.execute(url);
DownloadTask1 class
private class DownloadTask1 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);
ParserTask1 parserTask = new ParserTask1();
// Invokes the thread for parsing the JSON data
parserTask.execute(result);
}
private String getDirectionsUrl1(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&alternatives=true&units=metric&mode=driving";
//&alternatives=true&units=metric&mode=driving
// 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;
}
}
downloadUrl（）方法
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){
e.printStackTrace();
//Log.d("Exception while downloading url", e.toString());
}finally{
iStream.close();
urlConnection.disconnect();
}
return data;
}
ParserTask1类
private class ParserTask1 extends AsyncTask<String, Integer, List<List<List<HashMap<String, String>>>>> {
// Parsing the data in non-ui thread
@Override
protected List<List<List<HashMap<String, String>>>> doInBackground(String... jsonData) {
JSONObject jObject;
List<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<List<HashMap<String, String>>>> result) {
ArrayList<LatLng> points = null;
PolylineOptions lineOptions = new PolylineOptions();
PolylineOptions lineOptions1 = null;
MarkerOptions markerOptions = new MarkerOptions();
String distance = "";
String duration = "";
Integer size1 = 0;
Integer size2 = 0;
Integer size3 = 0;
// Log.d(SHETTY, "onPostExecute: result set "+result.size());
List<LatLng> aline1 = new ArrayList<LatLng>();
List<LatLng> aline2 = new ArrayList<LatLng>();
List<LatLng> aline3 = new ArrayList<LatLng>();
if (result != null) {
int i = 0;
Log.d(SHETTY, "onPostExecute: result size " + result.size());
while (i < result.size()) {
// for(int i=0;i<result.size();i++){
//result.size()
//int g= i-1;
points = new ArrayList<LatLng>();
// lineOptions = new PolylineOptions();
// if(i==1){
// }else{
List<List<HashMap<String, String>>> path1 = result.get(i);
for (int s = 0; s < path1.size(); s++) {
Log.d("pathsize1", path1.size() + "");
// Fetching i-th route
List<HashMap<String, String>> path = path1.get(s);
Log.d("pathsize", path.size() + "");
// Fetching all the points in i-th route
for (int j = 0; j < path.size(); j++) {
lineOptions1 = new PolylineOptions();
HashMap<String, String> point = path.get(j);
// points = new ArrayList<LatLng>();
// 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);
// Log.d("latlng", position.toString());
points.add(position);
}
// lineOptions.addAll(points);
// lineOptions.width(5);
// lineOptions.color(Color.BLUE);
// map.addPolyline(lineOptions);
}
// }
if (i == 0) {
// line1.addAll(points);
// mMap.addPolyline(line1);
size1 = points.size();
aline1.addAll(points);
} else if (i == 1) {
// line2.addAll(points);
// mMap.addPolyline(line2);
aline2.addAll(points);
size2 = points.size();
} else if (i == 2) {
// line3.addAll(points);
// mMap.addPolyline(line3);
aline3.addAll(points);
size3 = points.size();
}
// Adding all the points in the route to LineOptions
i++;
}
// Drawing polyline in the Google Map for the i-th route
// map.addPolyline(lineOptions);
}
if (size3 != 0)
{
if ((size1 > size2 && size1 > size3)) {
if (size2 > size3) {
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line2 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line3 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
line1.addAll(aline1);
line2.addAll(aline2);
line3.addAll(aline3);
mMap.addPolyline(line1);
mMap.addPolyline(line2);
mMap.addPolyline(line3);
Log.d(SHETTY, "onPostExecute: 3110 ");
} else {
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line2 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
PolylineOptions line3 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
line1.addAll(aline1);
line2.addAll(aline2);
line3.addAll(aline3);
mMap.addPolyline(line1);
mMap.addPolyline(line3);
mMap.addPolyline(line2);
Log.d(SHETTY, "onPostExecute: 3127 ");
}
} else if ((size2 > size1 && size2 > size3)) {
if (size1 > size3) {
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line2 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line3 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
line1.addAll(aline1);
line2.addAll(aline2);
line3.addAll(aline3);
mMap.addPolyline(line1);
mMap.addPolyline(line2);
mMap.addPolyline(line3);
Log.d(SHETTY, "onPostExecute: 3147 ");
} else {
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
PolylineOptions line2 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line3 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
line1.addAll(aline1);
line2.addAll(aline2);
line3.addAll(aline3);
mMap.addPolyline(line2);
mMap.addPolyline(line3);
mMap.addPolyline(line1);
Log.d(SHETTY, "onPostExecute: 3164 ");
}
} else if ((size3 > size1 && size3 > size2)) {
if (size1 > size2) {
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line2 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
PolylineOptions line3 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
line1.addAll(aline1);
line2.addAll(aline2);
line3.addAll(aline3);
mMap.addPolyline(line3);
mMap.addPolyline(line1);
mMap.addPolyline(line2);
Log.d(SHETTY, "onPostExecute: 3182 ");
} else {
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
PolylineOptions line2 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line3 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
line1.addAll(aline1);
line2.addAll(aline2);
line3.addAll(aline3);
mMap.addPolyline(line3);
mMap.addPolyline(line2);
mMap.addPolyline(line1);
Log.d(SHETTY, "onPostExecute: 3196 ");
}
} else {
System.out.println("ERROR!");
}
}else if(size2!=0)
{
if(size1>size2){
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line2 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
line1.addAll(aline1);
line2.addAll(aline2);
mMap.addPolyline(line1);
mMap.addPolyline(line2);
}else
{
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
PolylineOptions line2 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
line1.addAll(aline1);
line2.addAll(aline2);
mMap.addPolyline(line2);
mMap.addPolyline(line1);
}
}
else if(size1!=0){
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
line1.addAll(aline1);
mMap.addPolyline(line1);
}
}
}
现在解析JObject创建DirectionsJSONParser类
public class DirectionsJSONParser {
/**
* Receives a JSONObject and returns a list of lists containing latitude and
* longitude
*/
public List<List<List<HashMap<String,String>>>> parse(JSONObject jObject){
List<List<HashMap<String, String>>> routes = new ArrayList<List<HashMap<String,String>>>() ;
List<List<List<HashMap<String,String>>>> routes1 = new ArrayList<List<List<HashMap<String,String>>>>() ;
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<HashMap<String, String>>();
List path1 = new ArrayList<ArrayList<HashMap<String,String>>>();
// Log.d("legs",jLegs.toString());
/** Traversing all legs */
for(int j=0;j<jLegs.length();j++){
HashMap<String, String> hm1 = new HashMap<String, String>();
jSteps = ( (JSONObject)jLegs.get(j)).getJSONArray("steps");
// Log.d("steps",jSteps.toString());
/** 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);
// Log.d("polyline",polyline.toString());
/** 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);
// Log.d("lat", Double.toString(((LatLng)list.get(l)).latitude));
// Log.d("lng", Double.toString(((LatLng)list.get(l)).longitude));
}
}
path1.add(path);
}
routes1.add(path1);
}
} catch (JSONException e) {
e.printStackTrace();
}catch (Exception e){
}
return routes1;
}
/**
* Method to decode polyline points
* Courtesy : http://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;
}
}
最后，您将拥有蓝色的主要路线和灰色的替代路线。 希望它有所帮助。
答案 1 :(得分：0)
Google Directions API有4种不同的绘制路线参数。 https://developers.google.com/maps/documentation/directions/#TravelModes
driving，walking，bicycling，transit
因此您可以使用此参数并尝试获取不同的路径。
有时它们在彼此靠近的位置之间可以彼此相等（例如walking和bicycling）。
但是你可以处理这个并且不要画重复。
此外，您可以尝试创建一种机制，用于在地图上的2个点之间绘制路线（可能只是直线:)）。但是如果你想要一些复杂的东西，你自己很难创造它。