How to smoothly keep moving current location marker in Google Maps v2 android

Question

I have placed a marker for my location. I would like to move my marker smoothly something like the Google maps app. The blue circle moves very smoothly when I keep moving in my car. I would like implement the same for my app. how do I implement this on my app?

As of now my location marker just jumps for different location on very location change and marks the marker there.

Here is what I have don:

 googleMap.setMyLocationEnabled(true);

So onMyLocationChange method is called automatically:

@Override
public void onMyLocationChange(Location location) 
{
    curlat = location.getLatitude();
    curlong = location.getLongitude();

    if (markermylocation != null)
    {
        markermylocation.remove();
    }

        curlat = location.getLatitude();
        curlong = location.getLongitude();
        myLocation(curlat, curlong, username, imageURL, ZOOMVALUE);
}

in mylocaiton method:

private void myLocation(double lat, double lng, String name, String url, float zoom)
{
    if(firsttime  == 1)
    {
        LatLng ll = new LatLng(lat,lng);
        CameraUpdate update = CameraUpdateFactory.newLatLngZoom(ll, zoom);
        googleMap.animateCamera(update);
        firsttime = 0;
    }

    final String uname = name; 
    curlat = lat;
    curlong = lng;
    LatLng position = new LatLng(curlat, curlong);

    markerOptionsmylocaiton = new MarkerOptions().position(position).icon(BitmapDescriptorFactory.fromBitmap(icon)).title(uname).anchor(0.5f, 1f);
    markermylocation = googleMap.addMarker(markerOptionsmylocaiton);

    LatLng latlang = new LatLng(curlat, curlong);
    animateMarker(markermylocation, latlang, false);
}

So everytime mylocation is called the marker gets removed and calls mylocation method and then creates the marker in the new postition. Instead I would like to get a smooth transition of the marker like Google maps? How to implement this?

Update:

After working couple of times on this: I came to this code finally but then my markers are not showing up:

I am using the below method and calling this every time in myLocation method.

public void animateMarker(final Marker marker, final LatLng toPosition,
        final boolean hideMarker) 
{
    final Handler handler = new Handler();
    final long start = SystemClock.uptimeMillis();
    Projection proj = googleMap.getProjection();
    Point startPoint = proj.toScreenLocation(marker.getPosition());
    final LatLng startLatLng = proj.fromScreenLocation(startPoint);
    final long duration = 500;

    final Interpolator interpolator = new LinearInterpolator();

    handler.post(new Runnable() 
    {
        @Override
        public void run() 
        {
            long elapsed = SystemClock.uptimeMillis() - start;
            float t = interpolator.getInterpolation((float) elapsed
                    / duration);
            double lng = t * toPosition.longitude + (1 - t)
                    * startLatLng.longitude;
            double lat = t * toPosition.latitude + (1 - t)
                    * startLatLng.latitude;
            marker.setPosition(new LatLng(lat, lng));

            if (t < 1.0) 
            {
                // Post again 16ms later.
                handler.postDelayed(this, 16);
            } 
            else 
            {
                if (hideMarker) 
                {
                    marker.setVisible(false);
                } 
                else 
                {
                    marker.setVisible(true);
                }
            }
        }
    });
}

Thanks!

Answer 1

Hi I have also the same thing in one of my project and it works like charm.

Add the below piece of code after this line :

marker.setPosition(new LatLng(lat, lng));

 //this code
 if (googleMap != null)
         googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(lat, lng), 15.0f));

Hope it will help you. Thanks

Answer 2

You'll have to use an interpolator a linear or maybe an acceleration interpolator between the new latlng of the location and the current latlng of the marker. Here's an example with a bounce interpolator.

final Handler handler = new Handler();
        final long start = SystemClock.uptimeMillis();
        final long duration = 2500;

        final Interpolator interpolator = new BounceInterpolator();
        marker.setVisible(true);

        handler.post(new Runnable() {
            @Override
            public void run() {
                long elapsed = SystemClock.uptimeMillis() - start;
                float t = Math.max(
                        1 - interpolator.getInterpolation((float) elapsed
                                / duration), 0);

                marker.setAnchor(0.5f, 1.0f + 6 * t);
                marker.setPosition(latlng)

                if (t > 0.0) {
                    // Post again 16ms later.
                    handler.postDelayed(this, 16);
                }
            }
        });