Friends, Am able to fetch the latitude and longitude from SqliteDb to place a marker in google Map respectively. But my problem is 1. I want to draw a route from current location to the latitude and longitude fetched from Sqlite Db 2. The db values of Latitude and Longitude will be changed every 2 minutes and i want to change the place in marker accordingly and also route between the updated values and current location.
I have tried running the below code. It runs perfect in Main class but when I tried using thread it fails and since used timer for the same.
protected void mLocActivity() {
db.open();
class preciLoc extends TimerTask{
@Override
public void run() {
Cursor cr = db.fetchone(sLoc, "pos_mark", tblName, "pho", null, null);
if(cr.getCount()>0){
sLat = cr.getString(cr.getColumnIndex("lat"));
sLon = cr.getString(cr.getColumnIndex("lon"));
}
LatLng orgLoc = new LatLng(mLatitude,mLongitude);
LatLng desCur = new LatLng(Double.parseDouble(sLat), Double.parseDouble(sLon));
String url = getDirectionsUrl(orgLoc, desCur);
DownloadTask downloadTask = new DownloadTask();
downloadTask.execute(url);
rMap.moveCamera(CameraUpdateFactory.newLatLng(latLng))
CameraPosition camPos1 = new CameraPosition.Builder()
.target(destCurr).zoom(15).bearing(90).tilt(30).build();
rMap.animateCamera(CameraUpdateFactory
.newCameraPosition(camPos1));
drawMarker(desCur);
}
}
Timer timer = new Timer();
timer.schedule(new preciLoc(), 50000);
}
The solutions to your question are :-
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;
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>>();
/** 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<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
* */
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;
}
}Include the above class and then add the following codes to the class where you want to display the route to the map-
/** 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();
// 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);
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(4);
lineOptions.color(Color.RED);
}
// Drawing polyline in the Google Map for the i-th route
map.addPolyline(lineOptions);
}
}
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;
}Now the call starts as follows-
// Getting URL to the Google Directions API
String url = getDirectionsUrl(new LatLng(userLocation.getLatitude(),
userLocation.getLongitude()), new LatLng(
dest_lat, dest_long));
DownloadTask downloadTask = new DownloadTask();
// Start downloading json data from Google Directions API
downloadTask.execute(url);Here user userLocation is my current location and dest_lat, dest_long is the destination lat, long and in onPostExecute of ParserTask the line "map.addPolyline(lineOptions);" adds route to the map, so replace it with your own map.
Here is my implementation of timerTask and its working fine -
public class Test extends Activity {
Timer timer;
preciLoc loc;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.test);
..........
timer = new Timer();
loc = new preciLoc();
timer.schedule(loc,5000, 10000);
}
class preciLoc extends TimerTask {
@Override
public void run() {
Log.e("preciLoc", timer.toString());
}
}
}Here I have set a constant delay of 10 sec and a initial delay of 5 sec, its working fine.