How to bind google map markers in a circle?

Question

I need to bind multiple markers in a google map circle. I am calling following method from onMapReady to load markers:

void addMarker()
{
 mMap.clear();
    for (int i = 0; i < response.getData().getCount(); i++) {
        float lat = response.getData().get(i).getLat();
        float lng = response.getData().get(i).getLng();
........
........

 LatLng location = new LatLng(lat, lng);
 Marker mapMarker = mMap.addMarker(new MarkerOptions()
        .position(location)
         .draggable(false)
         .icon(bitmapMarker));
  mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(location, 17));
}

@Override
public void onMapReady(GoogleMap googleMap) {
   mMap = googleMap;
   addMarkers();
   DraggableCircle circle = new DraggableCircle(LOCATION, DEFAULT_RADIUS); 
}

As per above code I am able to draw a circle at given location and add markers on given coordinates . Everything is working fine like If I am increasing the size of circle then the map will adjust the zoom size as per screen dimensions.

Now What I am looking for:

1. Markers will be shown on screen which is coming under to circle diameters (location and radius)
2. As soon as user increase the radius new markers will get appear.

Any hint or help will be appreciable.

Answer 1

I hope i did not misunderstand you.

At bottom there is a seekbar, whenever you change it, also changes circle radius too.

Then i'm filtering markers by new radius value in filterMarkers method

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap;
    private SeekBar mRadiusSeekBar;

    private Circle mCircle;
    private double mCircleRadius = 250;
    private LatLng mCircleCenter = new LatLng(38.432398, 27.155882);

    private void addCircle(){
        mCircle = mMap.addCircle(new CircleOptions()
                .strokeWidth(4)
                .radius(mCircleRadius)
                .center(mCircleCenter)
                .strokeColor(Color.parseColor("#D1C4E9"))
                .fillColor(Color.parseColor("#657C4DFF")));
    }

    private List<LatLng> mPoints = new ArrayList<>();
    private List<Marker> mMarkers = new ArrayList<>();

    private void addMarkers(){
        LatLng mPoint1 = new LatLng(38.440925, 27.153672);
        LatLng mPoint2 = new LatLng(38.440700, 27.155877);
        LatLng mPoint3 = new LatLng(38.438402, 27.153988);
        LatLng mPoint4 = new LatLng(38.433767, 27.155410);
        LatLng mPoint5 = new LatLng(38.432143, 27.156049);
        LatLng mPoint6 = new LatLng(38.427804, 27.153486);
        LatLng mPoint7 = new LatLng(38.424637, 27.152007);
        LatLng mPoint8 = new LatLng(38.421315, 27.153216);
        LatLng mPoint9 = new LatLng(38.418219, 27.154731);
        LatLng mPoint10 = new LatLng(38.414628, 27.156085);

        mPoints.add(mPoint1);
        mPoints.add(mPoint2);
        mPoints.add(mPoint3);
        mPoints.add(mPoint4);
        mPoints.add(mPoint5);
        mPoints.add(mPoint6);
        mPoints.add(mPoint7);
        mPoints.add(mPoint8);
        mPoints.add(mPoint9);
        mPoints.add(mPoint10);

        BitmapDescriptor bd = BitmapDescriptorFactory
                .defaultMarker(BitmapDescriptorFactory.HUE_VIOLET);

        for(int i = 0; i<mPoints.size(); i++){
            Marker marker = mMap.addMarker(
                    new MarkerOptions()
                            .visible(false)
                            .position(mPoints.get(i)).icon(bd));

            mMarkers.add(marker);
        }
    }

    private void filterMarkers(double radiusForCircle){
        mCircle.setRadius(radiusForCircle);
        float[] distance = new float[2];
        for(int m = 0; m < mMarkers.size(); m++){
            Marker marker = mMarkers.get(m);
            LatLng position = marker.getPosition();
            double lat = position.latitude;
            double lon = position.longitude;

            Location.distanceBetween(lat, lon, mCircleCenter.latitude,
                    mCircleCenter.longitude, distance);

            boolean inCircle = distance[0] <= radiusForCircle;
            marker.setVisible(inCircle);
        }
    }




    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);

        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

        mRadiusSeekBar = (SeekBar) findViewById(R.id.seekbar);

        mRadiusSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                filterMarkers(progress * 10);
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {

            }
        });
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
        mMap.moveCamera(CameraUpdateFactory
                .newLatLngZoom(mCircleCenter, 12));

        addMarkers();
        addCircle();
    }
}

layout

<FrameLayout android:layout_height="match_parent"
android:layout_width="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android">

<fragment xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/map"
    android:name="com.google.android.gms.maps.SupportMapFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.blackkara.mapquestions.MapsActivity" />

<android.support.v7.widget.AppCompatSeekBar
    android:id="@+id/seekbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom"/>
</FrameLayout>