Develop Reference

How to show the track route using poly line in Android

I am developing a bus tracking application where I am getting the location using service from server. Now, with that I want to show the bus movement and draw a proper polyline. I achieved a part of this but facing two main issues:
Every time bus marker is showing, it is not getting removed. So, the older footprint of the bus is still present. Although I reached destination, I am seeing many bus icons.
I am able to draw the polyline by joining the latitude and longitude but it is showing sometimes a straight line.
I have attached two screenshots for that.
The code which I used is here:
private void setmMap() {
progressDialog.show();
if (broadcastReceiver == null)
broadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
Log.d("Testing", "inside the setmap");
// show progress dialog
try {
double latitude = intent.getDoubleExtra("lat", 22.560214);
double longitude = intent.getDoubleExtra("longi", 22.560214);
Log.d("SetMap", intent.getExtras().getString("time"));
LatLng startLocation = new LatLng(latitude, longitude);
m.setPosition(startLocation);
points.add(startLocation);
PolylineOptions options = new PolylineOptions().width(5).color(Color.BLUE).geodesic(true);
for (int i = 0; i < points.size(); i++) {
LatLng point = points.get(i);
options.add(point);
}
line = mMap.addPolyline(options); //add Polyline
mMap.moveCamera(CameraUpdateFactory.newLatLng(startLocation));
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(startLocation, 15));
progressDialog.cancel();
Geocoder geocoder;
List<Address> addresses;
geocoder = new Geocoder(context, Locale.getDefault());
addresses = geocoder.getFromLocation(latitude, longitude, 1);
String address = addresses.get(0).getAddressLine(0); // If any additional address line present than only, check with max available address lines by getMaxAddressLineIndex()
String city = addresses.get(0).getLocality();
String state = addresses.get(0).getAdminArea();
String country = addresses.get(0).getCountryName();
String postalCode = addresses.get(0).getPostalCode();
String strLoc = "Latitude:: "+latitude+" ::Longitude:: "+longitude+" ::Address:: "+address+" "+city+" "+
state;
Toast.makeText(getApplicationContext(),strLoc, Toast.LENGTH_LONG).show();
} catch (Exception e) {
e.printStackTrace();
progressDialog.cancel();
}
}
};
registerReceiver(broadcastReceiver, new IntentFilter("carLocationService"));
}
Thanks,
Arindam.

1) you din't show part of code where marker m added, possible that code runs several times;
2) seems bus location sensor's polling period is quite large and does not allow tracking bus turns (bus can make several turns between it's known locations). So you need to interpolate path between known bus locations for example with Google Directions API.

Plotting coordinates on Route in Gmap (Google Maps Android API)

I'm currently working on one Android application using Google map.
My requirement is to draw a route between source-destination and plot markers at every 500 meters on that route.
I have drawn a route, but not getting how to plot markers at every 500 meters. Is there any Google API available to get coordinates on route, or I have to implement any other logic?

Objectives
The objective is getting a list of LatLng coordinates along the route returned by the Directions API web service at every N meters. Later we can create markers for this list of coordinates.
Solution
The solution has two steps. The first one is getting a list of LatLng that form a route returned by Directions API. You can use a Java Client for Google Maps Services to execute Directions API request and extract a list of LatLng. Have a look at private List<LatLng> getDirectionsPathFromWebService(String origin, String destination) method in my example. This method calls Directions API and loop through legs and steps of the route object to get a complete list of LatLng that form a route.
The second step is implemented in the method private List<LatLng> getMarkersEveryNMeters(List<LatLng> path, double distance). It loops through all LatLng from the first step and creates a list of LatLng at every N meters where N is a distance in meters passed as a second parameter of the method. This method uses internally SphericalUtil class from the Google Maps Android API Utility Library. Have a look at comment to figure out what is happening in this method.
Finally, I create markers from the list that was obtained in second step.
Code snippet
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
private GoogleMap mMap;
private String TAG = "so47784512";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
#Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
String origin = "Avinguda Diagonal, 101, 08005 Barcelona, Spain";
String destination = "Carrer de París, 67, 08029 Barcelona, Spain";
LatLng center = new LatLng(41.391942,2.179413);
//Define list to get all latlng for the route
List<LatLng> path = this.getDirectionsPathFromWebService(origin, destination);
//Draw the polyline
if (path.size() > 0) {
PolylineOptions opts = new PolylineOptions().addAll(path).color(Color.BLUE).width(5);
mMap.addPolyline(opts);
}
List<LatLng> markers = this.getMarkersEveryNMeters(path, 500.0);
if (markers.size() > 0) {
for (LatLng m : markers) {
MarkerOptions mopts = new MarkerOptions().position(m);
mMap.addMarker(mopts);
}
}
mMap.getUiSettings().setZoomControlsEnabled(true);
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(center, 13));
}
private List<LatLng> getDirectionsPathFromWebService(String origin, String destination) {
List<LatLng> path = new ArrayList();
//Execute Directions API request
GeoApiContext context = new GeoApiContext.Builder()
.apiKey("AIzaSyBrPt88vvoPDDn_imh-RzCXl5Ha2F2LYig")
.build();
DirectionsApiRequest req = DirectionsApi.getDirections(context, origin, destination);
try {
DirectionsResult res = req.await();
//Loop through legs and steps to get encoded polylines of each step
if (res.routes != null && res.routes.length > 0) {
DirectionsRoute route = res.routes[0];
if (route.legs !=null) {
for(int i=0; i<route.legs.length; i++) {
DirectionsLeg leg = route.legs[i];
if (leg.steps != null) {
for (int j=0; j<leg.steps.length;j++){
DirectionsStep step = leg.steps[j];
if (step.steps != null && step.steps.length >0) {
for (int k=0; k<step.steps.length;k++){
DirectionsStep step1 = step.steps[k];
EncodedPolyline points1 = step1.polyline;
if (points1 != null) {
//Decode polyline and add points to list of route coordinates
List<com.google.maps.model.LatLng> coords1 = points1.decodePath();
for (com.google.maps.model.LatLng coord1 : coords1) {
path.add(new LatLng(coord1.lat, coord1.lng));
}
}
}
} else {
EncodedPolyline points = step.polyline;
if (points != null) {
//Decode polyline and add points to list of route coordinates
List<com.google.maps.model.LatLng> coords = points.decodePath();
for (com.google.maps.model.LatLng coord : coords) {
path.add(new LatLng(coord.lat, coord.lng));
}
}
}
}
}
}
}
}
} catch(Exception ex) {
Log.e(TAG, ex.getLocalizedMessage());
}
return path;
}
private List<LatLng> getMarkersEveryNMeters(List<LatLng> path, double distance) {
List<LatLng> res = new ArrayList();
LatLng p0 = path.get(0);
res.add(p0);
if (path.size() > 2) {
//Initialize temp variables for sum distance between points and
//and save the previous point
double tmp = 0;
LatLng prev = p0;
for (LatLng p : path) {
//Sum the distance
tmp += SphericalUtil.computeDistanceBetween(prev, p);
if (tmp < distance) {
//If it is less than certain value continue sum
prev = p;
continue;
} else {
//If distance is greater than certain value lets calculate
//how many meters over desired value we have and find position of point
//that will be at exact distance value
double diff = tmp - distance;
double heading = SphericalUtil.computeHeading(prev, p);
LatLng pp = SphericalUtil.computeOffsetOrigin(p, diff, heading);
//Reset sum set calculated origin as last point and add it to list
tmp = 0;
prev = pp;
res.add(pp);
continue;
}
}
//Add the last point of route
LatLng plast = path.get(path.size()-1);
res.add(plast);
}
return res;
}
}
Conclusion
You can see a result of sample code in the following screenshot
The sample project can be found on GitHub:
https://github.com/xomena-so/so47784512
Do not forget to replace an API key with your's.
I hope this helps!

How to update the blue dot marker for current location in MapView in Android

I have a fragment which when normally launched shows a mapview with current user location shown as blue dot marker. I have a feature to launch this screen from another place and can pass latitude and longitude values. Based on these values, I update the latitude and longitude of "MapboxMap". The location is updated on map and camera zooms to it but blue dot marker still shows as user current location. How can I update the blue dot marker to be shown as new location given by latitude and longitude value:
My code to update location:
private void goToUserLocation() {
double requestedLatitude = 0;
double requestedLongitude = 0;
if (mapboxMap == null || !getUserVisibleHint()) {
return;
}
if (!DeviceUtil.isLocationServiceEnabled(getContext().getApplicationContext())) {
showLocationDisabledSnackbar();
return;
}
enableUserLocationMarker();
Location location = mapboxMap.getMyLocation();
//Get the requested coordinates if it exists
if(location != null) {
try {
Uri intentData = getActivity().getIntent().getData();
if (null != intentData) {
String latitude = intentData.getQueryParameter("lat");
String longitude = intentData.getQueryParameter("lon");
if (!TextUtils.isEmpty(latitude) && !TextUtils.isEmpty(longitude)) {
requestedLatitude = Double.parseDouble(latitude);
requestedLongitude = Double.parseDouble(longitude);
if ((requestedLatitude >= -90 && requestedLatitude <= 90) &&
(requestedLongitude >= -90d && requestedLongitude <= 90d)) {
location.setLatitude(requestedLatitude);
location.setLongitude(requestedLongitude);
}
}
}
}catch (NumberFormatException ex) {
}
finally {
goToLocation(location);
}
}
fetchNearbyPages();
}
Any help is appreciated.

Hi hope this will help.
First, override the onLocatioChanged method and pass the updated location to separate created setCameraToCurrentPosition method. ex. is as follows:-
public void onLocationChanged(Location location) {
setCameraToCurrentPosition(Location location);
}
private void setCameraToCurrentPosition(Location location) {
setCameraPosition(new LatLng(location.getLatitude(), location.getLongitude()), 16, 6500);
// Here you need to add the marker to current position of user on map.
}

How to get the latitude and longitude of location where user taps on the map in android

In my Android application, I'm using google maps v2 to show map by getting the latitute and longitude of the device's current location And I'm showing pin on that location.
Now when user clicks or taps on any other location on the map, then I have to get that points latitude and longitude and i have to set the pin at that location.
Could you please tell me how get the latitude and longitude of the user taps/clicks location.

An example of what i use. Change it accordingly for your needs. I use it with long press.
map.setOnMapLongClickListener(new OnMapLongClickListener() {
#Override
public void onMapLongClick(LatLng point) {
map.addMarker(new MarkerOptions().position(point).title("Custom location").icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED)));enter code here
}
});
the LatLng point contains the coordinated of the longpress

Try to use google-maps v2 built-in method.
map.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
#Override
public void onMapClick(LatLng position) {
Toast.makeText(context,position.latitude+" : "+position.longitude,Toast.LENGTH_SHORT).show();
}
});

Try the following.
Write a class which derives from the Overlay class and override the onTap() method. Then you can add your overlay to the your MapView. A GeoPoint object, which represents the position of you tap, is passed to the onTap() method when you tab somewhere on the map.
OR
The modern answer here, using Android Maps v2, is to use OnMapClickListener, which gives you the LatLng of a tap on the map.

// Setting onclick event listener for the map
mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
#Override
public void onMapClick(LatLng point) {
// Creating MarkerOptions
MarkerOptions options = new MarkerOptions();
// Setting the position of the marker
options.position(point);
//Get LatLng from touched point
double touchLat=point.latitude;
double touchLong=point.longitude;
///here is reverse GeoCoding which helps in getting address from latlng
try {
Geocoder geo = new Geocoder(MainActivity.this.getApplicationContext(), Locale.getDefault());
List<Address> addresses = geo.getFromLocation(touchLat,touchLong, 1);
if (addresses.isEmpty()) {
Toast.makeText(getApplicationContext(),"Waiting for Location",Toast.LENGTH_SHORT).show();
}
else {
if (addresses.size() > 0) {
address =addresses.get(0).getFeatureName()
+ ", " + addresses.get(0).getLocality()
+ ", " + addresses.get(0).getAdminArea()
+ ", " + addresses.get(0).getCountryName();
Toast.makeText(getApplicationContext(), "Address:- " +address, Toast.LENGTH_LONG).show();
}
// draws the marker at the currently touched location
drawMarker(point,"Your Touched Position",address+"");
}
}
catch (Exception e) {
e.printStackTrace(); // getFromLocation() may sometimes fail
}

How to get Current Lat Lng position on GMAPS API V3?

I'm trying to calculate my route, from my current position to the specific location (var: end). How I suppose to get my LatLng from my current position ? Thx
Here's my Code :
function calcRoute() {
var start = "How to get this LatLng ?";
var end = new google.maps.LatLng(-6.28529,106.871542);
var request = {
origin:start,
destination:end,
travelMode: google.maps.TravelMode.WALKING
};
directionsService.route(request, function(result, status) {
if (status == google.maps.DirectionsStatus.OK) {
directionsDisplay.setDirections(result);
}
});
}

If you have a Location object (lets call it location), all you need to do is LatLng mLatLng = new LatLng(location.getLatitude(), location.getLongitude()) and you will have a LatLng object. location.getLatitude() returns a double corresponding to the latitude in degrees and location.getLongitude() returns the same but for longitude. See the documentation for more details: http://developer.android.com/reference/android/location/Location.html