I'm working on a project that the main part is to visually demonstrates directions between two points on Google Maps, but I want this direction do pass from specific point like A and B. I fount this solution:
final Intent intent = new Intent(Intent.ACTION_VIEW,Uri.parse("http://maps.google.com/maps?" + "saddr="+ source.latitude + "," + source.longitude+ "&daddr=" + dest.latitude+ "," + dest.longitude));
intent.setClassName("com.google.android.apps.maps","com.google.android.maps.MapsActivity");
startActivity(intent);
but the problem is that the route is not flexible and I have no control over it. is there any solution to my problem like changing the 'XML' source of the route?
If you're obtaining the route by explicitly parsing an URL to Google try the following code, it will allow you to set the PolyLine parameters:
// URL constructor
public String makeURL (double sourcelat, double sourcelog, double destlat, double destlog ){
StringBuilder urlString = new StringBuilder();
urlString.append("http://maps.googleapis.com/maps/api/directions/json");
urlString.append("?origin=");// from
urlString.append(Double.toString(sourcelat));
urlString.append(",");
urlString.append(Double.toString( sourcelog));
urlString.append("&destination=");// to
urlString.append(Double.toString( destlat));
urlString.append(",");
urlString.append(Double.toString( destlog));
urlString.append("&sensor=false&mode=walking&alternatives=true");
return urlString.toString();
}
// draws path from result String
public void drawPath(String result) {
try {
//Tranform the string into a json object
final JSONObject json = new JSONObject(result);
JSONArray routeArray = json.getJSONArray("routes");
JSONObject routes = routeArray.getJSONObject(0);
JSONObject overviewPolylines = routes.getJSONObject("overview_polyline");
String encodedString = overviewPolylines.getString("points");
List<LatLng> list = decodePoly(encodedString);
for(int z = 0; z<list.size()-1;z++){
LatLng src= list.get(z);
LatLng dest= list.get(z+1);
map.addPolyline(new PolylineOptions()
.add(new LatLng(src.latitude, src.longitude), new LatLng(dest.latitude, dest.longitude))
.width(8)
.color(Color.BLUE).geodesic(true));
}
}
catch (JSONException e) {
}
}
// obtain route using AsyncTask
private class connectAsyncTask extends AsyncTask<Void, Void, String>{
private ProgressDialog progressDialog;
String url;
connectAsyncTask(String urlPass){
url = urlPass;
}
@Override
protected void onPreExecute() {
super.onPreExecute();
progressDialog = new ProgressDialog(DisplayOnMapActivity.this);
progressDialog.setMessage(getResources().getString(R.string.waitCoord));
progressDialog.setIndeterminate(true);
progressDialog.show();
}
@Override
protected String doInBackground(Void... params) {
JSONParser jParser = new JSONParser();
String json = jParser.getJSONFromUrl(url);
return json;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
progressDialog.hide();
if(result!=null){
drawPath(result);
}
}
}
public void drawPath(LatLng src, LatLng dest) {
String url = makeURL(src.latitude,src.longitude,dest.latitude,dest.longitude);
new connectAsyncTask(url).execute();
}
// decodes encoded String into PolyLine object
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;
}
You will also need the JSONParser class:
public class JSONParser {
static InputStream is = null;
static JSONObject jobj = null;
static String json = "";
public JSONParser(){
}
public JSONObject makeHttpRequest(String url){
DefaultHttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(url);
try {
HttpResponse httpresponse = httpclient.execute(httppost);
if(httpresponse!=null){
HttpEntity httpentity = httpresponse.getEntity();
is = httpentity.getContent();
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
if(is!=null){
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
StringBuilder sb = new StringBuilder();
String line = null;
try {
while((line = reader.readLine())!=null){
sb.append(line+"\n");
}
is.close();
json = sb.toString();
try {
jobj = new JSONObject(json);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
} catch (Exception e){
// TODO Auto-generated catch block
e.printStackTrace();
}
return jobj;
}
public String getJSONFromUrl(String url) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
json = sb.toString();
is.close();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
return json;
}
}