Develop Reference

Dynamically draw a single polyline to current location

In my android app, I want to create a single path/polyline from a specific location(far end) to my current location while moving. I could draw the polyline on map with now issue while when I moves to a new location another polyline is been drown on the map, so my map output is full of polylines whichh I don't need, I want only one polyline to be visible to my current location.
PolylineOptions polylineOptions = new PolylineOptions().add(currentPosition).add(farEndPosition).width(10).color(Color.GREEN);
Polyline polyline = googleMap.addPolyline(polylineOptions);

Remove old Line before adding new one.
Polyline polyline ;
public void addUpdatePolyLine()
{
PolylineOptions polylineOptions = new PolylineOptions().add(currentPosition).add(farEndPosition).width(10).color(Color.GREEN);
if(polyline !=null)
{
polyline.remove();
}
polyline = googleMap.addPolyline(polylineOptions);
}

Adding LatLon to Polygon android google map version 2 from list

I have a list full of LatLng points to create a polygon in google maps android v2, but I cannot figure out how to add this list to the .add area correctly. Here is my list full of points:
list.add(new LatLng(la,lo));
Here is the polygon via Google Dev
Polygon polygon = map.addPolygon(new PolygonOptions()
.add(*******HOW TO ITTERATE LIST************).strokeColor(Color.RED)
.fillColor(Color.BLUE));
How do you go about adding the points?

PolygonOptions opts=new PolygonOptions();
for (LatLng location : list) {
opts.add(location);
}
Polygon polygon = map.addPolygon(opts.strokeColor(Color.RED).fillColor(Color.BLUE));
This assumes that list is something like an ArrayList<LatLng>.

I had the same issue and I find this without need for iteration.
PolygonOptions polOpt =
new PolygonOptions().addAll(latlngs).strokeColor(Color.RED).fillColor(Color.BLUE);
Polygon polygon = mMap.addPolygon(polOpt);

It may help someone. I did the same its working.
ArrayList<LatLng> locations = new ArrayList();
Adding the latLng value in list.
locations .add(new LatLng(2, 2));
locations .add(new LatLng(4, 2));
locations .add(new LatLng(4, 4));
locations .add(new LatLng(2, 4));
locations .add(new LatLng(2, 2))
Creating the GeoFence on the map
PolylineOptions options = new PolylineOptions().width(5).color(Color.RED).geodesic(true);
for (int z = 0; z < locations.size(); z++) {
LatLng point = locations.get(z);
options.add(point);
}
mMap.addPolyline(options);
CameraPosition cameraPosition;
cameraPosition = new CameraPosition.Builder().target(new LatLng(50.8404969, -0.1504184)).zoom(15).build();
mMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));

How can I get the visible markers in Google Maps v2 in Android?

In Google Maps v2 for Android, how can I get the visible markers? I know I can use Projection and eliminate points < 0 and points > screen size. But I do not wish to check one by one, it can be too slow if I have a lot of markers. Is there any easy way? Or some off-the-shelf solution? If yes, which one?

Ok, the following is the code the I have used before to determine what the user can see and then only draw the markers that are visible.
I think you might be able to adapt it to your purpose.
get the current rectangle "viewport" of the map (note:must be run on the main thread)
this.mLatLngBounds = this.mMap.getProjection().getVisibleRegion().latLngBounds;
sort the 2 points (top-left and bottom-right) so that we can use min/max logic
double lowLat;
double lowLng;
double highLat;
double highLng;
if (this.mLatLngBounds.northeast.latitude < this.mLatLngBounds.southwest.latitude)
{
lowLat = this.mLatLngBounds.northeast.latitude;
highLat = this.mLatLngBounds.southwest.latitude;
}
else
{
highLat = this.mLatLngBounds.northeast.latitude;
lowLat = this.mLatLngBounds.southwest.latitude;
}
if (this.mLatLngBounds.northeast.longitude < this.mLatLngBounds.southwest.longitude)
{
lowLng = this.mLatLngBounds.northeast.longitude;
highLng = this.mLatLngBounds.southwest.longitude;
}
else
{
highLng = this.mLatLngBounds.northeast.longitude;
lowLng = this.mLatLngBounds.southwest.longitude;
}
then in my case I had this data in a db, so i could use >= and <= to extract only the pins i wanted

You could use the android-map-extension library. Amongst others it offers a List GoogleMap.getDisplayedMarkers() method.

You could add this Extension Function to GoogleMap class if you are using Kotlin
fun GoogleMap.isMarkerVisible(markerPosition: LatLng) =
projection.visibleRegion.latLngBounds.contains(markerPosition)
You just pass the marker position as a parameter of this method and do whatever you want with the result.
If you are using Java you can just declare the function wherever fits better for you.
Hope it helps!

You are looking for either markers:
https://developers.google.com/maps/documentation/android/marker
private GoogleMap mMap;
mMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();
mMap.addMarker(new MarkerOptions()
.position(new LatLng(0, 0))
.title("Hello world"));
Or direct drawing:
https://developers.google.com/maps/documentation/android/shapes
// Instantiates a new Polyline object and adds points to define a rectangle
PolylineOptions rectOptions = new PolylineOptions()
.add(new LatLng(37.35, -122.0))
.add(new LatLng(37.45, -122.0)) // North of the previous point, but at the same longitude
.add(new LatLng(37.45, -122.2)) // Same latitude, and 30km to the west
.add(new LatLng(37.35, -122.2)) // Same longitude, and 16km to the south
.add(new LatLng(37.35, -122.0)); // Closes the polyline.
// Get back the mutable Polyline
Polyline polyline = myMap.addPolyline(rectOptions);

Unwanted polyline extension when zoom in and disappears on zoom out on android Map

I connected map locations using Polyline API. It creates polyline properly.But sometimes unwanted polyline extended when zoom in and disappears on zoom out.
My code:
locations.clear();
for(int i=0;i<maplatitude.size();i++)
{
locations.add(new LatLng(maplatitude.get(i), maplongitude.get(i)));
}
PolylineOptions rectOptions = new PolylineOptions();
rectOptions.addAll(locations);
// Get back the mutable Polyline
Polyline polyline = mMap.addPolyline(rectOptions);
for(int i=0;i<maplatitude.size();i++)
{
//mMap.addMarker(new MarkerOptions().position(new LatLng(maplatitude.get(i), maplongitude.get(i))).title(name).snippet(mapdate.get(i)+"\n"+maptime.get(i)));
mMap.addMarker(new MarkerOptions().position(new LatLng(maplatitude.get(i), maplongitude.get(i))).icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_AZURE)).title(String.valueOf(i)));
}

I solved this: it's a bug from Google. We must filter some close points within 1 or 2 meters.
Polylines appearing on map where they shouldn't

How to remove all the polylines from a map

Following
How to draw a path between two markers
I had to add lot of polylines between two markers, to make a path.
One of the markers is draggable, lets say source is draggable.
So, when user starts dragging the marker, the path previously drawn must be erased and a new path between new source and destination must be draw.
I am able to draw the new path, but how can i erase the previous path?
This is how the path is drawn:
for (int z = 0; z < list.size() - 1; z++) {
LatLng src = list.get(z);
LatLng dest = list.get(z + 1);
Polyline line = map.addPolyline(new PolylineOptions()
.add(new LatLng(src.latitude, src.longitude),
new LatLng(dest.latitude, dest.longitude))
.width(2).color(Color.RED).geodesic(true));
}
One solution i can get is
map.clear();
To clear all the polylines, markers etc.. and add the markers again, then drawn the path.
But as soon as I start dragging, the marker is cleared, hence not visible on the map :(
Thank You

Keep track of the Polyline as you add it to the map:
Polyline polyline = this.mMap.addPolyline(new PolylineOptions().....);
Then when you want to remove it:
polyline.remove();
If you have lots of Polylines, just add them to a List as they are put on the map:
List<Polyline> polylines = new ArrayList<Polyline>();
for(....)
{
polylines.add(this.mMap.addPolyline(new PolylineOptions()....));
}
And when you want to delete:
for(Polyline line : polylines)
{
line.remove();
}
polylines.clear();
The key is to keep a reference to the Polyline objects and call .remove() on each one.

I know this is very old question but I noticed that this is very common need. I found another way and I wanted to share it.
Here is the basic idea:
Polyline polylineFinal;
PolylineOptions polylineOptions;
loop {
polylineOptions.add( new LatLng( latitude, longitude ) );
}
polylineOptions.width(2);
polylineOptions.color(Color.RED);
polylineOptions.geodesic(true);
polylineFinal = map.addPolyline (polylineOptions);
Map's "addPolyline" method returns a single polyline which contains all the points. When I need to remove the points, I call polylineFinal's "remove" method.
polylineFinal.remove();

Update
If you want to removes all markers, polylines, polygons, overlays, etc from the map use
mMap.clear(); //it will remove all additional objects from map
and if you only want to remove all or single polyline, polygon, marker etc see #DiskDev Answer above. In this case you must keep track of every single additional object you add to map