Develop Reference

Android-How to set location in map

I have this map and I want to set the location to the lat , lon that I receive in the Intent extras.How can I do it?
public class MapActivity extends AppCompatActivity implements OnMapReadyCallback {
private SupportMapFragment mMapFragment;
private GoogleMap mGoogleMap;
private String lat;
private String lon;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_map);
lat=getIntent().getStringExtra("lat");
lon=getIntent().getStringExtra("lon");
mMapFragment=(SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
mMapFragment.getMapAsync(this);
}
#Override
public void onMapReady(GoogleMap googleMap) {
mGoogleMap=googleMap;
}
}

put this code in onMapReady
double lat = location.getLatitude();
double lng= location.getLongitude();
// set up marker and add
googleMap.addMarker(new MarkerOptions().position(new LatLng(lat , lng))
.title("Location").icon(BitmapDescriptorFactory
.defaultMarker(BitmapDescriptorFactory.HUE_RED)));
// move camera to it
googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(lat, lng), 8));
always do all map-related features like drawing polygons, adding markers, moving camera etc. after onMapReady call, so when googleMap won't be null. And remember that even if it gets called every time for you - in some circulumstances it may not get fired on some device and every googleMap.someMethod() call (e.g. under onClick) will throw you NullPointerException. be prepared for that

Zoom map Get location chosen by User and pass it to activity

I have this code, that allows a user to select a location (mechanic_location) and passes it to another activity(mechanic_login). The problem is, it does not zoom. Help me enable it to zoom to the current location the user is in but give the user the ability to pick another location different from the one that he/she is in. Once the location is picked, click a button to send the latitude and longitude to the view (mechanic_login). Here is my code
public class mechanic_location extends FragmentActivity implements OnMapReadyCallback {
private GoogleMap mMap;
Button mSendLocationBtn;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_mechanic_location);
// 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;
mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
#Override
public void onMapClick(LatLng latLng) {
Intent returnIntent = new Intent();
returnIntent.putExtra("picked_point",latLng);
setResult(Activity.RESULT_OK,returnIntent);
finish();
}
});
}
}

You can use the moveCamera() Method and defined the zoom level
float zoomLevel = 16.0f; //This goes up to 21
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, zoomLevel));
for mor information about using google map, you can check it here
source

Android - How to get latitude and longitude values from outside OnMapReady function?

I have this EventActivity where I have a map with a marker:
public class EventActivity extends AppCompatActivity implements OnMapReadyCallback {
private double latitude;
private double longitude;
private GoogleMap eventMap;
#Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_event);
// Declares map fragment.
SupportMapFragment eventMapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.activity_event_map);
eventMapFragment.getMapAsync(this);
// Gets latitude and longitude values from database.
// (things happen here and I get the values correctly)
latitude = 12.4567785
longitude = 25.7773665
}
#Override
public void onMapReady(GoogleMap googleMap) {
eventMap = googleMap;
// Sets map position.
LatLng position = new LatLng(latitude, longitude);
eventMap.addMarker(new MarkerOptions().position(position));
eventMap.moveCamera(CameraUpdateFactory.newLatLng(position));
}
}
On the OnCreate() I get the pair of double values correctly. I can even make a toast and it shows them.
The problem is, when I want to set them as the position for the marker of my map on the OnMapReady() it gets nothing or null.
How can I properly pass the values from OnCreate() to OnMapReady()?
EDIT: I'm using Firebase as my database.

Perhaps initialize the map fragment after assigning the lat/long values as such:
public class EventActivity extends AppCompatActivity implements OnMapReadyCallback {
private double latitude;
private double longitude;
private GoogleMap eventMap;
#Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_event);
// Gets latitude and longitude values from database.
// (things happen here and I get the values correctly)
latitude = 12.4567785
longitude = 25.7773665
// Declares map fragment.
SupportMapFragment eventMapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.activity_event_map);
eventMapFragment.getMapAsync(this);
}
#Override
public void onMapReady(GoogleMap googleMap) {
eventMap = googleMap;
// Sets map position.
LatLng position = new LatLng(latitude, longitude);
eventMap.addMarker(new MarkerOptions().position(position));
eventMap.moveCamera(CameraUpdateFactory.newLatLng(position));
}
}

I needed to solve a similar issue and currently have this solution working in my app. I wanted to add a new polyline from my location to the marker in question so wanted setOnMarkerListener to have access to my location. Here is how I solved it:
Step 1.
I created two global doubles as follows:
private Double myLatitude = -33.865143;
private Double myLongitude = 151.209900;
I gave them a default value of Sydney to avoid any NullPointerException error as I am adding polylines to an array of polylines.
Step 2.
In my onLocationChanged method I updated the values:
#Override
public void onLocationChanged(Location location) {
myLatitude = location.getLatitude();
myLongitude = location.getLongitude();
....
Now in Step 3 I wanted to create a new line from mylocation to the selected marker so used the following code:
mMap.setOnMarkerClickListener(new GoogleMap.OnMarkerClickListener() {
#Override
public boolean onMarkerClick(Marker marker) {
marker.showInfoWindow();
areaText.setText(marker.getTitle());
distanceText.setText("0 Meters");
markerLatitude = marker.getPosition().latitude;
markerLongitude = marker.getPosition().longitude;
lines.add(mMap.addPolyline(new PolylineOptions()
.add(new LatLng(myLatitude, myLongitude),
new LatLng(marker.getPosition().latitude, marker.getPosition().longitude))
.width(10)
.color(Color.RED)));
if (lines.size() > 1)
lines.remove((lines.size()-1));
return true;
}
});
Hope this helps someone with the same issue.

I want to replace a Marker from a map when user visits that location ( gets near a Marker )

First, I plot a Marker like this:
public void addMarker(String title,String lat,String Lng,int id,String address,int f)
{
marker= mMap.addMarker(new MarkerOptions().snippet(title)
.title(title+", "+address)
.position(new LatLng(Double.valueOf(lat), Double.valueOf(Lng)))
.icon(BitmapDescriptorFactory.fromResource(id)));
LatLng coordinate = new LatLng(Double.valueOf(lat), Double.valueOf(Lng));
CameraUpdate yourLocation = CameraUpdateFactory.newLatLngZoom(coordinate, 10);
mMap.animateCamera(yourLocation);
mMarkerArray.add(marker);
}
After that I am trying to replace the Marker with another icon when ever I reached at any existing Location
#Override
public void onLocationChanged(Location location)
{
Log.d("latitude_main", "onlocation???");
Geocoder geocoder;
List<Address> addresses;
geocoder = new Geocoder(this, Locale.getDefault());
double latitude = location.getLatitude();
double longitude = location.getLongitude();
Log.e("latitude_main", "latitude--" + latitude+"longitude="+longitude);
current_lat= String.valueOf(latitude);
current_lng= String.valueOf(longitude);
Log.e("latitude_main","size-=="+salesmanlocationArrayList.size() );
for(int i=0;i<salesmanlocationArrayList.size();i++)
{
if(salesmanlocation.getLati().equals("12.9165757") && salesmanlocation.getLongi().equals("77.6101163"))
{
mMap.addMarker(new MarkerOptions()
.snippet(""+i).title(salesmanlocation.getFirm_name()+", "+salesmanlocation.getAddress())
.position(new LatLng(Double.valueOf(salesmanlocation.getLati().toString()), Double.valueOf(salesmanlocation.getLongi().toString())))
.icon(BitmapDescriptorFactory.fromResource(R.drawable.event_events_select)));
}
mapFragment.getMapAsync(this);
}
}
I want to remove the marker from the map when the user visits that location.

You can simply define one OnMyLocationChangeListener class that performs your tasks, and set it on your GoogleMap instance, this way you can use it whenever you want in your application.
Step 1 - define your listener
public class MyMarkerLocationListener implements GoogleMap.OnMyLocationChangeListener {
List<Marker> markerList;
int MY_DISTANCE;
GoogleMap mMap;
public MyMarkerLocationListener(List<Marker> markerList, int meters, GoogleMap mMap)
{
this.markerList = markerList;
this.MY_DISTANCE = meters;
this.mMap = mMap;
}
#Override
public void onMyLocationChange(Location location) {
// your code/logic
//...
Location myNewLocation = location;
Location someMarkerLocation = new Location("some location");
//for each marker on your list
//check if you are close to it
for (Marker m : markerList) {
LatLng markerPosition = m.getPosition();
someMarkerLocation.setLatitude(markerPosition.latitude);
someMarkerLocation.setLongitude(markerPosition.longitude);
if (myNewLocation.distanceTo(someMarkerLocation) < MY_DISTANCE) {
//remove marker
m.remove();
//or if you still want to use it later
//m.setVisible(false);
// add your new marker
//mMap.addMarker(new MarkerOptions().icon()....);
}
}
}
}
After defining your class you just set the listener on your map on your fragment or activity code =)
Step 2 - instanciate the listener and set it
MyMarkerLocationListener myListener = new MyMarkerLocationListener(mMarkerArray, 100, mMap);
mMap.setOnMyLocationChangeListener(myListener);
UPDATE to answer your question in the comments:
You should initialize mMap before using it, take a look at this piece of code from this Stackoverflow question
public class MapPane extends Activity implements OnMapReadyCallback {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.map_activity);
MapFragment mapFragment = (MapFragment) getFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
#Override
public void onMapReady(GoogleMap map) {
//DO WHATEVER YOU WANT WITH GOOGLEMAP
map.setMapType(GoogleMap.MAP_TYPE_HYBRID);
map.setMyLocationEnabled(true);
map.setTrafficEnabled(true);
map.setIndoorEnabled(true);
map.setBuildingsEnabled(true);
map.getUiSettings().setZoomControlsEnabled(true);
}
}
don't forget your activity should implement the OnMapReadyCallback interface so the onMapReady method is called
you can use the map only after it is ready
Hope this helps!

Restrict android map marker drag to polyline

I'm looking for some suggestions on how I could approach a problem I'm facing with an android SupportMapFragment. I am drawing a polyline on a SupportMapFragment using LatLng co-ordinance stored in my apps db. I am also adding a map marker at the first and last LatLng co-ordinance to signify the start and end of the route. I would like to provide my users with the ability to trim the route by dragging the start and end markers to their desired points on the polyline. The problem I am facing is restricting the path the markers can be dragged across so they can only be moved along the polyline.

This questions is a little bit old, but I hope others would find this answer useful.
boolean PolyUtil.isLocationOnEdge will help you determine wether a point overlaps a Polygon or Polyline on the map.
public class RestrictedMarkerDragActivity extends FragmentActivity implements
OnMapReadyCallback,
GoogleMap.OnMarkerDragListener {
private static final float WIDTH = 4;
private static final double TOLERANCE_IN_METERS = 3.0;
private GoogleMap map;
private SupportMapFragment mapFragment;
private Polyline polyline;
private Marker marker;
private LatLng positionOnPolyline;
#Override
protected void onCreate(Bundle savedInstance) {
super.onCreate(savedInstance);
setContentView(R.layout.activity_maps);
mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
#Override
public void onMapReady(GoogleMap googleMap) {
this.map = googleMap;
List<LatLng> points = new ArrayList<>();
points.add(new LatLng(19.35853391311947, -99.15182696733749));
points.add(new LatLng(19.34384275931999, -99.1546209261358));
PolylineOptions polylineOptions = new PolylineOptions();
polylineOptions.color(Color.CYAN);
polylineOptions.width(WIDTH);
polyline = map.addPolyline(polylineOptions);
polyline.setPoints(points);
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.draggable(true);
markerOptions.position(points.get(0));
marker = map.addMarker(markerOptions);
positionOnPolyline = new LatLng(marker.getPosition().latitude, marker.getPosition().longitude);
map.setOnMarkerDragListener(this);
map.animateCamera(CameraUpdateFactory.newLatLngZoom(points.get(0), 15));
}
#Override
public void onMarkerDragStart(Marker marker) {
//Nothing to do here
}
#Override
public void onMarkerDrag(Marker marker) {
//If the marker overlaps the polyline, polyline width gets bigger and marker position gets updated,
//else, polyline width remains the same
if(PolyUtil.isLocationOnEdge(marker.getPosition(), polyline.getPoints(), true, TOLERANCE_IN_METERS)) {
polyline.setWidth(WIDTH * 3);
positionOnPolyline = new LatLng(marker.getPosition().latitude, marker.getPosition().longitude);
} else {
polyline.setWidth(WIDTH);
}
}
#Override
public void onMarkerDragEnd(Marker marker) {
//We set the marker to its last known position over the polyline
marker.setPosition(positionOnPolyline);
//We set polyline width to its original
polyline.setWidth(WIDTH);
}
}