Highlight area in Google Maps v2

Question

How can I highlight an area/region on Google Maps v2 Android? I also have a list of geopoints of that particular region. It needs to highlight that region when you scroll to that region. It needs to fill color for nearby region to differentiate from each other so each region should have a different color.

Answer 1

You need to draw a polygon by selecting some points on map. Here is the code.

MainActivity.java

public class MainActivity extends FragmentActivity implements
    OnMapClickListener, 
    OnMapLongClickListener, 
    OnMarkerClickListener {

    private GoogleMap myMap;
    Location myLocation;
    boolean markerClicked;
    PolygonOptions polygonOptions;
    Polygon polygon;

    @Override
    protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        FragmentManager manager = getSupportFragmentManager();
        SupportMapFragment mapFragment = (SupportMapFragment) manager
            .findFragmentById(R.id.map);
        myMap = mapFragment.getMap();
        myMap.setMyLocationEnabled(true);
        myMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
        myMap.setOnMapClickListener(this);
        myMap.setOnMapLongClickListener(this);
        myMap.setOnMarkerClickListener(this);
        markerClicked = false;
    }

    @Override
    public void onMapLongClick(LatLng point) 
    {
        myMap.addMarker(new MarkerOptions()
            .position(point).title(point.toString()));

        markerClicked = false;
    }

    @Override
    public boolean onMarkerClick(Marker marker) 
    {

        if(markerClicked)
        {
            if(polygon != null)
            {
                polygon.remove();
                polygon = null;
            }

            polygonOptions.add(marker.getPosition());
            polygonOptions.strokeColor(Color.BLACK);
            polygonOptions.strokeWidth(5);
            polygonOptions.fillColor(0x884d4d4d);

            polygon = myMap.addPolygon(polygonOptions);
            marker.remove();

        }
        else    
        {
            if(polygon != null)
            {
                polygon.remove();
                polygon = null;
            }

            polygonOptions = new PolygonOptions().add(marker.getPosition());
            markerClicked = true;
            marker.remove();
        }

        return true;
    }

    @Override
    public void onMapClick(LatLng point) 
    {
        Toast.makeText(getApplicationContext(), 
            "Long Press to select locations", Toast.LENGTH_LONG).show();
    }
}

activity_main

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  tools:context=".MainActivity" >


 <fragment
    android:id="@+id/map"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    class="com.google.android.gms.maps.SupportMapFragment" />


</RelativeLayout>

manfiest file

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.polygononmap"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

     <permission
        android:name="com.example.googlemapwithsession.permission.MAPS_RECEIVE"
        android:protectionLevel="signature" />

    <uses-feature
        android:glEsVersion="0x00020000"
        android:required="true" />

    <uses-permission android:name="google.map.ver2.permission.MAPS_RECEIVE" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>


    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.polygononmap.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <meta-data
            android:name="com.google.android.maps.v2.API_KEY"
            android:value="your api key" />
    </application>

</manifest>

now use long press to select points on map and click on marker will draw polygon accordingly.. I thing this will help.

• http://www.youtube.com/watch?v=YEM90r9r9vI
• for details https://developers.google.com/maps/documentation/android/reference/com/google/android/gms/maps/model/Polygon

Answer 2

You just draw a Polygon on your map and fill it with the color you need.