Semi Transparent color for FillColor in Google Maps Android API V2

In this article, we will develop a Google Map Android API V2 application with a circle at the touched position where the circle is filled with a semi transparent color.

This application is developed in Eclipse (4.2.1) with ADT plugin (21.1.0) and Android SDK (21.1.0) and tested in a real Android device (Android 2.3.6  -  GingerBread).

1. Create a new Android application project namely “SemiTransparentDemo”

Figure 1 : Create new Android application project namely "SemiTransparentDemo"

2. Configure the project

Figure 2 : Configure the application project

3. Design application launcher icon

Figure 3 : Design application launcher icon

4. Create a blank activity

Figure 4 : Create a blank activity

5. Enter MainActivity details

Figure 5 : Enter MainActivity details

6. Download and configure Google Play Services Library in Eclipse

Google Map for Android is now integrated with Google Play Services. So we need to set up Google Play Service Library for developing Google Map application in Android.

Please follow the given below link to setup Google Play Service library in Eclipse.

http://developer.android.com/google/play-services/setup.html

7. Add Google Play Services Library to this project

Figure 6 : Link Google Play Services Library to this project

8. Get the API key for Google Maps Android API V2

We need to get an API key from Google to use Google Maps in Android application.

Please follow the given below link to get the API key for Google Maps Android API v2.

https://developers.google.com/maps/documentation/android/start

9. Add Android Support library to this project

By default, Android support library (android-support-v4.jar ) is added to this project by Eclipse IDE to the directory libs. If it is not added, we can do it manually by doing the following steps :

• Open Project Explorer by Clicking “Window -> Show View -> Project Explorer”
• Right click this project
• Then from popup menu, Click “Android Tools -> Add Support Library “

10. Update the layout file res/layout/activity_main.xml

<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>

11. Update the class “MainActivity” in the file src/in/wptrafficanalyzer/semitransparentdemo/MainActivity.java

package in.wptrafficanalyzer.semitransparentdemo;

import android.app.Dialog;
import android.graphics.Color;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.Menu;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMap.OnMapClickListener;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.CircleOptions;
import com.google.android.gms.maps.model.LatLng;

public class MainActivity extends FragmentActivity {

    GoogleMap googleMap;

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

        // Getting Google Play availability status
        int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getBaseContext());

        // Showing status
        if(status!=ConnectionResult.SUCCESS){ // Google Play Services are not available

            int requestCode = 10;
            Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status, this, requestCode);
            dialog.show();

        }else { // Google Play Services are available

            // Getting reference to the SupportMapFragment of activity_main.xml
            SupportMapFragment fm = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);

            // Getting GoogleMap object from the fragment
            googleMap = fm.getMap();

            // Enabling MyLocation button for the Google Map
            googleMap.setMyLocationEnabled(true);

            googleMap.setOnMapClickListener(new OnMapClickListener() {

                @Override
                public void onMapClick(LatLng point) {

                    // Removes the existing marker from the Google Map
                    googleMap.clear();

                    // Instantiating CircleOptions to draw a circle around the marker
                    CircleOptions circleOptions = new CircleOptions();

                    // Specifying the center of the circle
                    circleOptions.center(point);

                    // Radius of the circle
                    circleOptions.radius(50);

                    // Border color of the circle
                    circleOptions.strokeColor(Color.BLACK);

                    // Fill color of the circle
                    // 0x represents, this is an hexadecimal code
                    // 55 represents percentage of transparency. For 100% transparency, specify 00.
                    // For 0% transparency ( ie, opaque ) , specify ff
                    // The remaining 6 characters(00ff00) specify the fill color
                    circleOptions.fillColor(0x5500ff00);

                    // Border width of the circle
                    circleOptions.strokeWidth(2);

                    // Adding the circle to the GoogleMap
                    googleMap.addCircle(circleOptions);
                }
            });
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
}

12. Update the file AndroidManifest.xml

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

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

    <permission
        android:name="in.wptrafficanalyzer.semitransparentdemo.permission.MAPS_RECEIVE"
        android:protectionLevel="signature"/>

    <uses-permission android:name="in.wptrafficanalyzer.semitransparentdemo.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-feature
        android:glEsVersion="0x00020000"
        android:required="true"/>

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="in.wptrafficanalyzer.semitransparentdemo.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_ANDROID_API_KEY"/>

    </application>
</manifest>

13. Screenshot of the application

Figure 7 : Showing Semi Transparent Circle in Google Map Android API V2

14. Download the source code

Semi Transparent color for FillColor in Google Maps Android API V2 - R1 359.19 KB

Download Full Source Code

How to hire me?

I am George Mathew, working as software architect and Android app developer at wptrafficanalyzer.in

You can hire me on hourly basis or on project basis for Android applications development.

For hiring me, please mail your requirements to info@wptrafficanalyzer.in.

My other blogs
store4js.blogspot.com

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Tags: Circle, CircleOptions, fillColor, Google Map, Google Map Android API V2, map, SupportMapFragment, transparent