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Using Google Maps in Android

POSTED BY WEIMENGLEE - 06 APR 2009

See also...

• Developing with Google Maps v2 for Android
• Using the Google Maps API to display mobile-friendly maps on all devices
• Android forks: Why Google can rest easy. For now
• Will Chinese device manufacturers usher in global smartphone era?
• Geo-sorting: Using Device Geolocation to Sort by Distance

Google Maps is one of the many applications bundled with the Android platform. In addition to simply using the Maps application, you can also embed it into your own applications and make it do some very cool things. In this article, I will show you how to use Google Maps in your Android applications and how to programmatically perform the following:

1. Change the views of Google Maps
2. Obtain the latitude and longitude of locations in Google Maps
3. Perform geocoding and reverse geocoding
4. Add markers to Google Maps

(Note: we cover Google Maps API v2 here.)

Creating the Project

Using Eclipse, create a new Android project and name GoogleMaps as shown in Figure 1.

Figure 1 Creating a new Android project using Eclipse

Obtaining a Maps API key

Beginning with the Android SDK release v1.0, you need to apply for a free Google Maps API key before you can integrate Google Maps into your Android application. To apply for a key, you need to follow the series of steps outlined below. You can also refer to Google's detailed documentation on the process athttp://code.google.com/android/toolbox/apis/mapkey.html.

First, if you are testing the application on the Android emulator, locate the SDK debug certificate located in the default folder of "C:\Documents and Settings\\Local Settings\Application Data\Android". The filename of the debug keystore is debug.keystore. For deploying to a real Android device, substitute the debug.keystore file with your own keystore file. In a future article I will discuss how you can generate your own keystore file.

For simplicity, copy this file (debug.keystore) to a folder in C:\ (for example, create a folder called "C:\Android").

Using the debug keystore, you need to extract its MD5 fingerprint using the Keytool.exe application included with your JDK installation. This fingerprint is needed to apply for the free Google Maps key. You can usually find the Keytool.exefrom the "C:\Program Files\Java\\bin" folder.

Issue the following command (see also Figure 2) to extract the MD5 fingerprint.

keytool.exe -list -alias androiddebugkey -keystore "C:\android\debug.keystore" -storepass android -keypass android

Copy the MD5 certificate fingerprint and navigate your web browser to: http://code.google.com/android/maps-api-signup.html. Follow the instructions on the page to complete the application and obtain the Google Maps key.

Figure 2 Obtaining the MD5 fingerprint of the debug keystore

To use the Google Maps in your Android application, you need to modify your AndroidManifest.xml file by adding the element together with the INTERNET permission:

 version="1.0" encoding="utf-8"?>
 xmlns:android="http://schemas.android.com/apk/res/android"
      package="net.learn2develop.GoogleMaps"
      android:versionCode="1"
      android:versionName="1.0.0">
     android:icon="@drawable/icon" android:label="@string/app_name">
 
     android:name="com.google.android.maps" />  
 
         android:name=".MapsActivity"
                  android:label="@string/app_name">
            >
                 android:name="android.intent.action.MAIN" />
                 android:name="android.intent.category.LAUNCHER" />
            

> > >   android:name="android.permission.INTERNET" />   > >

Displaying the Map

To display the Google Maps in your Android application, modify the main.xml file located in the res/layout folder. You shall use the  element to display the Google Maps in your activity. In addition, let's use the  element to position the map within the activity:

 version="1.0" encoding="utf-8"?>
 xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent">
 
    .google.android.maps.MapView 
        android:id="@+id/mapView"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:enabled="true"
        android:clickable="true"
        android:apiKey="0l4sCTTyRmXTNo7k8DREHvEaLar2UmHGwnhZVHQ"
        />
 

>

Notice from above that I have used the Google Maps key that I obtained earlier and put it into the apiKey attribute.

In the MapsActivity.java file, modify the class to extend from the MapActivity class, instead of the normal Activityclass:

package net.learn2develop.GoogleMaps;
 
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapView;
import android.os.Bundle;
 
public class MapsActivity extends MapActivity 
{    
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }
 
    @Override
    protected boolean isRouteDisplayed() {
        return false;
    }
}

Observe that if your class extends the MapActivity class, you need to override the isRouteDisplayed() method. You can simply do so by setting the method to return false.

That's it! That's all you need to do to display the Google Maps in your application. Press F11 in Eclipse to deploy the application onto an Android emulator. Figure 3 shows the Google map in all its glory.

Figure 3 Google Maps in your application

At this juncture, take note of a few troubleshooting details. If your program does not run (i.e. it crashes), then it is likely you forgot to put the following statement in your AndroidManifest.xml file:

     android:name="com.google.android.maps" />

If your application manages to load but you cannot see the map (all you see is a grid), then it is very likely you do not have a valid Map key, or that you did not specify the INTERNET permission:

     android:name="android.permission.INTERNET" />

Displaying the Zoom View

The previous section showed how you can display the Google Maps in your Android device. You can drag the map to any desired location and it will be updated on the fly. However, observe that there is no way to zoom in or out from a particular location. Thus, in this section, you will learn how you can let users zoom into or out of the map.

First, add a  element to the main.xml file as shown below:

 version="1.0" encoding="utf-8"?>
 xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent">
 
    .google.android.maps.MapView 
        android:id="@+id/mapView"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:enabled="true"
        android:clickable="true"
        android:apiKey="0l4sCTTyRmXTNo7k8DREHvEaLar2UmHGwnhZVHQ"
        />
 
     android:id="@+id/zoom" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:layout_alignParentBottom="true" 
        android:layout_centerHorizontal="true" 
        /> 
 

>

You will use the  element to hold the two zoom controls in Google Maps (you will see this shortly).

In the MapsActivity.java file, add the following imports:

import com.google.android.maps.MapView.LayoutParams;  
import android.view.View;
import android.widget.LinearLayout;

and add the following code after the line setContentView(R.layout.main);

        mapView = (MapView) findViewById(R.id.mapView);
        LinearLayout zoomLayout = (LinearLayout)findViewById(R.id.zoom);  
        View zoomView = mapView.getZoomControls(); 
 
        zoomLayout.addView(zoomView, 
            new LinearLayout.LayoutParams(
                LayoutParams.WRAP_CONTENT, 
                LayoutParams.WRAP_CONTENT)); 
        mapView.displayZoomControls(true);

The complete MapsActivity.java file is given below:

package net.learn2develop.GoogleMaps;
 
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapView;
import com.google.android.maps.MapView.LayoutParams;  
 
import android.os.Bundle;
import android.view.View;
import android.widget.LinearLayout;
 
public class MapsActivity extends MapActivity 
{    
    MapView mapView; 
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
 
 
        mapView = (MapView) findViewById(R.id.mapView);
        LinearLayout zoomLayout = (LinearLayout)findViewById(R.id.zoom);  
        View zoomView = mapView.getZoomControls(); 
 
        zoomLayout.addView(zoomView, 
            new LinearLayout.LayoutParams(
                LayoutParams.WRAP_CONTENT, 
                LayoutParams.WRAP_CONTENT)); 
        mapView.displayZoomControls(true);
 
    }
 
    @Override
    protected boolean isRouteDisplayed() {
        // TODO Auto-generated method stub
        return false;
    }
}

Basically, you obtain the MapView instance on the activity, obtain its zoom controls and then add it to the LinearLayoutelement you added to the activity earlier on. In the above case, the zoom control will be displayed at the bottom of the screen. When you now press F11 in Eclipse, you will see the zoom controls when you touch the map (see Figure 4).

Figure 4 Using the zoom controls in Google Maps

Using the zoom control, you can zoom in or out of a location by simply touching the "+ or "-" buttons on the screen.

Alternatively, you can also programmatically zoom in or out of the map using the zoomIn() and zoomOut() methods from the MapController class:

package net.learn2develop.GoogleMaps;
 
//...
import android.os.Bundle;
import android.view.KeyEvent;
 
public class MapsActivity extends MapActivity 
{    
    MapView mapView; 
 
    public boolean onKeyDown(int keyCode, KeyEvent event) 
    {
        MapController mc = mapView.getController(); 
        switch (keyCode) 
        {
            case KeyEvent.KEYCODE_3:
                mc.zoomIn();
                break;
            case KeyEvent.KEYCODE_1:
                mc.zoomOut();
                break;
        }
        return super.onKeyDown(keyCode, event);
    }    
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        //...
    }
 
    @Override
    protected boolean isRouteDisplayed() {
        // TODO Auto-generated method stub
        return false;
    }
}

In the above code, when the user presses the number 3 on the keyboard the map will zoom in into the next level. Pressing number 1 will zoom out one level.

Changing Views of the Map

By default, the Google Maps displays in the map mode. If you wish to display the map in satellite view, you can use thesetSatellite() method of the MapView class, like this:

        mapView.setSatellite(true);

You can also display the map in street view, using the setStreetView() method:

        mapView.setStreetView(true);

Figure 5 shows the Google Maps displayed in satellite and street views, respectively.

Figure 5 Displaying Google Maps in satellite and street views

Displaying a Particular Location

Be default, the Google Maps displays the map of the United States when it is first loaded. However, you can also set the Google Maps to display a particular location. In this case, you can use the animateTo() method of theMapController class.

The following code shows how this is done:

package net.learn2develop.GoogleMaps;
 
import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapController;
import com.google.android.maps.MapView;
import com.google.android.maps.MapView.LayoutParams;
 
import android.os.Bundle;
import android.view.View;
import android.widget.LinearLayout;
 
public class MapsActivity extends MapActivity 
{    
    MapView mapView; 
    MapController mc;
    GeoPoint p;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
 
        mapView = (MapView) findViewById(R.id.mapView);
        LinearLayout zoomLayout = (LinearLayout)findViewById(R.id.zoom);  
        View zoomView = mapView.getZoomControls(); 
 
        zoomLayout.addView(zoomView, 
            new LinearLayout.LayoutParams(
                LayoutParams.WRAP_CONTENT, 
                LayoutParams.WRAP_CONTENT)); 
        mapView.displayZoomControls(true);
 
        mc = mapView.getController();
        String coordinates[] = {"1.352566007", "103.78921587"};
        double lat = Double.parseDouble(coordinates[0]);
        double lng = Double.parseDouble(coordinates[1]);
 
        p = new GeoPoint(
            (int) (lat * 1E6), 
            (int) (lng * 1E6));
 
        mc.animateTo(p);
        mc.setZoom(17); 
        mapView.invalidate();
    }
 
    @Override
    protected boolean isRouteDisplayed() {
        // TODO Auto-generated method stub
        return false;
    }
}

In the above code, you first obtain a controller from the MapView instance and assign it to a MapController object (mc). You use a GeoPoint object to represent a geographical location. Note that for this class the latitude and longitude of a location are represented in micro degrees. This means that they are stored as integer values. For a latitude value of 40.747778, you need to multiply it by 1e6 to obtain 40747778.

To navigate the map to a particular location, you can use the animateTo() method of the MapController class (an instance which is obtained from the MapView object). The setZoom() method allows you to specify the zoom level in which the map is displayed. Figure 6 shows the Google Maps displaying the map of Singapore.

Figure 6 Navigating to a particular location on the map

Adding Markers

Very often, you may wish to add markers to the map to indicate places of interests. Let's see how you can do this in Android. First, create a GIF image containing a pushpin (see Figure 7) and copy it into the res/drawable folder of the project. For best effect, you should make the background of the image transparent so that it does not block off parts of the map when the image is added to the map.

Figure 7 Adding an image to the res/drawable folder

To add a marker to the map, you first need to define a class that extends the Overlay class:

package net.learn2develop.GoogleMaps;
 
import java.util.List;
 
import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapController;
import com.google.android.maps.MapView;
import com.google.android.maps.Overlay;
import com.google.android.maps.MapView.LayoutParams;
 
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Point;
import android.os.Bundle;
import android.view.View;
import android.widget.LinearLayout;
 
public class MapsActivity extends MapActivity 
{    
    MapView mapView; 
    MapController mc;
    GeoPoint p;
 
    class MapOverlay extends com.google.android.maps.Overlay
    {
        @Override
        public boolean draw(Canvas canvas, MapView mapView, 
        boolean shadow, long when) 
        {
            super.draw(canvas, mapView, shadow);                   
 
            //---translate the GeoPoint to screen pixels---
            Point screenPts = new Point();
            mapView.getProjection().toPixels(p, screenPts);
 
            //---add the marker---
            Bitmap bmp = BitmapFactory.decodeResource(
                getResources(), R.drawable.pushpin);            
            canvas.drawBitmap(bmp, screenPts.x, screenPts.y-50, null);         
            return true;
        }
    } 
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        //...
    }
 
    @Override
    protected boolean isRouteDisplayed() {
        // TODO Auto-generated method stub
        return false;
    }
}

In the MapOverlay class that you have defined, override the draw() method so that you can draw the pushpin image on the map. In particular, note that you need to translate the geographical location (represented by a GeoPoint object, p) into screen coordinates.

As you want the pointed tip of the push pin to indicate the position of the location, you would need to deduct the height of the image (which is 50 pixels) from the y-coordinate of the point (see Figure 8) and draw the image at that location.

Figure 8 Adding an image to the map

To add the marker, create an instance of the MapOverlap class and add it to the list of overlays available on the MapViewobject:

    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
 
        //...
 
        mc.animateTo(p);
        mc.setZoom(17); 
 
        //---Add a location marker---
        MapOverlay mapOverlay = new MapOverlay();
        List<Overlay> listOfOverlays = mapView.getOverlays();
        listOfOverlays.clear();
        listOfOverlays.add(mapOverlay);        
 
        mapView.invalidate();
    }

Figure 9 shows how the pushpin looks like when added to the map.

Figure 9 Adding a marker to the map

Getting the Location that was touched

After using Google Maps for a while, you may wish to know the latitude and longitude of a location corresponding to the position on the screen that you have just touched. Knowing this information is very useful as you can find out the address of a location, a process known as Geocoding (you will see how this is done in the next section).

If you have added an overlay to the map, you can override the onTouchEvent() method within the Overlay class. This method is fired every time the user touches the map. This method has two parameters - MotionEvent and MapView. Using the MotionEvent parameter, you can know if the user has lifted his finger from the screen using the getAction()method. In the following code, if the user has touched and then lifted his finger, you will display the latitude and longitude of the location touched:

    class MapOverlay extends com.google.android.maps.Overlay
    {
        @Override
        public boolean draw(Canvas canvas, MapView mapView, 
        boolean shadow, long when) 
        {
           //...
        }
 
        @Override
        public boolean onTouchEvent(MotionEvent event, MapView mapView) 
        {   
            //---when user lifts his finger---
            if (event.getAction() == 1) {                
                GeoPoint p = mapView.getProjection().fromPixels(
                    (int) event.getX(),
                    (int) event.getY());
                    Toast.makeText(getBaseContext(), 
                        p.getLatitudeE6() / 1E6 + "," + 
                        p.getLongitudeE6() /1E6 , 
                        Toast.LENGTH_SHORT).show();
            }                            
            return false;
        }        
    }

Figure 10 shows this in action.

Figure 10 Displaying the latitude and longitude of a point touched on the map

Geocoding and Reverse Geocoding

If you know the latitude and longitude of a location, you can find out its address using a process known as Geocoding. Google Maps in Android supports this via the Geocoder class. The following code shows how you can find out the address of a location you have just touched using the getFromLocation() method:

    class MapOverlay extends com.google.android.maps.Overlay
    {
        @Override
        public boolean draw(Canvas canvas, MapView mapView, 
        boolean shadow, long when) 
        {
          //...
        }
 
        @Override
        public boolean onTouchEvent(MotionEvent event, MapView mapView) 
        {   
            //---when user lifts his finger---
            if (event.getAction() == 1) {                
                GeoPoint p = mapView.getProjection().fromPixels(
                    (int) event.getX(),
                    (int) event.getY());
 
                Geocoder geoCoder = new Geocoder(
                    getBaseContext(), Locale.getDefault());
                try {
                    List<Address> addresses = geoCoder.getFromLocation(
                        p.getLatitudeE6()  / 1E6, 
                        p.getLongitudeE6() / 1E6, 1);
 
                    String add = "";
                    if (addresses.size() > 0) 
                    {
                        for (int i=0; i<addresses.get(0).getMaxAddressLineIndex(); 
                             i++)
                           add += addresses.get(0).getAddressLine(i) + "\n";
                    }
 
                    Toast.makeText(getBaseContext(), add, Toast.LENGTH_SHORT).show();
                }
                catch (IOException e) {                
                    e.printStackTrace();
                }   
                return true;
            }
            else                
                return false;
        }        
    }

Figure 11 shows the above code in action.

Figure 11 Performing Geocoding in Google Maps

If you know the address of a location but want to know its latitude and longitude, you can do so via reverse-Geocoding. Again, you can use the Geocoder class for this purpose. The following code shows how you can find the exact location of the Empire State Building by using the getFromLocationName() method:

        Geocoder geoCoder = new Geocoder(this, Locale.getDefault());    
        try {
            List<Address> addresses = geoCoder.getFromLocationName(
                "empire state building", 5);
            String add = "";
            if (addresses.size() > 0) {
                p = new GeoPoint(
                        (int) (addresses.get(0).getLatitude() * 1E6), 
                        (int) (addresses.get(0).getLongitude() * 1E6));
                mc.animateTo(p);    
                mapView.invalidate();
            }    
        } catch (IOException e) {
            e.printStackTrace();
        }

Once the location is found, the above code navigates the map to the location. Figure 12 shows the code in action.

Figure 12 Navigating to the Empire State Building

Summary

In this article, you have learnt a few tricks for the Google Maps in Android. Using Google Maps, there are many interesting projects you can work on, such as geo-tagging, geo-tracking, etc. If you have cool ideas on building cool location-based services, share with us in the comments box below. Have fun!

POSTED BY WEIMENGLEE - 06 APR 2009

Wei-Meng Lee is a technologist and the founder of Developer Learning Solutions (http://www.learn2develop.net), a company focusing on hands-on training on the latest technology. Wei-Meng specializes in mobile technologies and has written several books on .NET, VB, C#, and .NET Compact Framework and is currently working on an Android book for Wrox. Contact Wei-Meng Lee at weimenglee@learn2develop.net.

• COMMENTS

 tag at the end says, it's missing its' start tag and there is a start tag.

Any ideas?

Here's my manifest:

POSTED BY AVDHESH 5 YEARS AGO

Hi,

Thanks for such a good article on maps. I found one issue in your block related to debug certificate on given locationC:\Documents and Settings\\Local Settings\Application Data\Android. When a generate the finger for specified location, after generating finger pint, i generate the api key. My app is running fine but i am not able to see any maps on emulator only grid view are there.

My problem is resolved when i get the debug key store on the given location:
C:\Documents and Settings\\.android\debug.keystore

Debug key store location on different operating systems.

➤ Windows Vista \users\\.android\debug.keystore
➤ Windows XP \Documents and Settings\\.android\debug.keystore
➤ Linux or Mac ∼/.android/debug.keystore

Hope this will help.

Thanks
Avdhesh

POSTED BY CNBISHOP 5 YEARS AGO

thanks for a great tutorial! i was wondering, how can i add an additional marker to the spot when the user touches the map?

POSTED BY TRIPPLE60 5 YEARS AGO

Hello, I would like to use your great example on using google maps in android to learn and explore how the code works in eclipse with the JDK. Could you email me the source code on this so I can begin experimenting? Much appreciated.tripple60@gmail.com

Matt

POSTED BY GAURID3 5 YEARS AGO

Hi, I got the debug key for my application. I have added INTERNET permission too. The app loads but doesn't show the map in emulator. What can be the reason? Does it work behind proxy?

POSTED BY VIVEKASOHAN 5 YEARS AGO

good sample ya i got everything correctly

vivekasohan

POSTED BY LEON01061988 4 YEARS AGO

Hi ! i have got the same problem about the first time with the map did not show anything, except only grid. I have follow all those steps, about getting MD5 finger print, and Google Maps API key, also Internet permission.
Anyone who 's solved this problem before, please reply to me soon, thanks!

Note: i have deployed on my own HTC phone (Wild Fire), may be there 's some different in set up environment or not ?

POSTED BY LEGEND 4 YEARS AGO

Great tutorial! Really appreciated for this great information for a newbee like me and it really helps!

POSTED BY KAMALONE 4 YEARS AGO

Hai ,

Thank you very much for the Great tutorial!! It Helped me a lot.

But i am getting error while modifying the code.

In my application has two xml file. One is first.xml and the other is main.xml

by starting first.xml is loading and it has viewMAP button. If click that going to main.xml and the map shows there.(It is showing correctly)

and the main.xml another buton is there for going back which allows the user to go back to first.XML(It is also working fine).

If i am again click the viewMAP button then the application shows "InfalteException:Binary xml file line #6: Error in inflating class ".

My Code is

XML files
 
1.first.xml
 


 
  
 

 
 
2.main.xml
 


 
    
 
    
 
         
 

 
    


 
 
 
public class HelloGoogleMaps extends MapActivity implements View.OnClickListener {
    Button view;
    Button back;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        try {
            super.onCreate(savedInstanceState);
            first();
        } catch (Exception e) {
            Toast.makeText(this, "" + e, 10).show();
        }
    }
 
    @Override
    protected boolean isRouteDisplayed() {
        return false;
    }
 
 
    public void first(){
        try{
            setContentView(R.layout.first);
            view = (Button) findViewById(R.id.view);
            view.setOnClickListener(this);
        }
        catch(Exception e){
            Toast.makeText(this, ""+e, 10).show();
        }
    }
 
 
    public void map() {
        try {
            setContentView(R.layout.main);
            MapView mapView = (MapView) findViewById(R.id.mapview);
            mapView.setBuiltInZoomControls(true);
            Double d = 52.093504;
            List mapOverlays = mapView.getOverlays();
            Drawable drawable = this.getResources().getDrawable(
                    R.drawable.pinpoint);
            HelloItemizedOverlay itemizedoverlay = new HelloItemizedOverlay(
                    drawable, this);
            GeoPoint point = new GeoPoint((int) (d * (1E6)),
                    (int) (5.1176533 * (1E6)));
            OverlayItem overlayitem = new OverlayItem(point,
                    "Laissez les bon temps rouler!", "I'm in Louisiana!");
            itemizedoverlay.addOverlay(overlayitem);
 
            mapOverlays.add(itemizedoverlay);
            mapView.invalidate();
            back = (Button) findViewById(R.id.back);
            back.setOnClickListener(this);
 
        } catch (Exception e) {
            Toast.makeText(this, "" + e, 10).show();
        }
    }
 
    @Override
    public void onClick(View v) {
        if (v == view) {           
            map();
        }
        else if(v==back){
            first();
        }
 
    }
}
 
Please Help,
Thank you.

POSTED BY DHRUVJOSHI 4 YEARS AGO

Hello

This is very nice tutorial.But I want to know if i want to overlay map more than 1 location.then what i have to do.can i write

My code is

location = new GeoPoint(230583152,725690172);
location1 = new GeoPoint(230395677,725660045);
HelloItemtizedOverlay overlay1 = new HelloItemtizedOverlay(drawable);
OverlayItem item = new OverlayItem(location,"", "");
overlay1.addOverlay(item);

location1 = new GeoPoint(230395677,725660045);
OverlayItem item2 = new OverlayItem(location1,"", "");
overlay1.addOverlay(item2);
mapView.getOverlays().add(overlay1);
MapOverlay mapOverlay = new MapOverlay();

MapOverlay mapOverlay1 = new MapOverlay();
List listOfOverlays = mapView.getOverlays();
listOfOverlays.clear();
listOfOverlays.add(mapOverlay);

and in MapOverlay class

mapView.getProjection().toPixels(location, screenPts);

mapView.getProjection().toPixels(location1, screenPts);

But i got only one overlay on the map.

can u help me. to display more than one overlay on google map.write some code line.thanks.Plz Reply Soon

POSTED BY DHRUVJOSHI 4 YEARS AGO

DhruvJoshi wrote:

Hello

This is very nice tutorial.But I want to know if i want to overlay map more than 1 location.then what i have to do.can i write

My code is

location = new GeoPoint(230583152,725690172);
location1 = new GeoPoint(230395677,725660045);
HelloItemtizedOverlay overlay1 = new HelloItemtizedOverlay(drawable);
OverlayItem item = new OverlayItem(location,"", "");
overlay1.addOverlay(item);

location1 = new GeoPoint(230395677,725660045);
OverlayItem item2 = new OverlayItem(location1,"", "");
overlay1.addOverlay(item2);
mapView.getOverlays().add(overlay1);
MapOverlay mapOverlay = new MapOverlay();

MapOverlay mapOverlay1 = new MapOverlay();
List listOfOverlays = mapView.getOverlays();
listOfOverlays.clear();
listOfOverlays.add(mapOverlay);

and in MapOverlay class

mapView.getProjection().toPixels(location, screenPts);

mapView.getProjection().toPixels(location1, screenPts);

But i got only one overlay on the map.

can u help me. to display more than one overlay on google map.write some code line.thanks.Plz Reply Soon

POSTED BY STELIOSCHAR 4 YEARS AGO

Hello,

Great tutorial...!!

Is there any way to draw a bubble that contains some information about the geotag??

POSTED BY FMLDEV 4 YEARS AGO

Awesome Tutorial! I've read 4 separate books on Android Development, this is by far the easiest to follow.

POSTED BY AHMED.NIYAS 4 YEARS AGO

Hi,
Recently i tried the same in android 2.2 SDK with google api version 8. But i m also facing the same problem, map is not displaying only grid lines are coming.
I tried opening maps through interner browser in that case it is working fine but when i tried with inbuilt map apps or my own app it is not displaying map.
anyone who resolved the same problem, please reply ASAP. Thankss in Advance

POSTED BY ZINGAR 4 YEARS AGO

hello Ahmed, i was having the same problem you have and i had tried everything.
turns out it was my mistake :P
i wasnt generating the API correctly, i had a typing error in the fingerprint and that made a invalid API key. once i figured that out i created a new API with the correct fingerprint and it worked!

good luck

POSTED BY DISHANF 4 YEARS AGO

Great tutorial! Thank You Mr Lee!

POSTED BY AHMED.NIYAS 4 YEARS AGO

Hi ZINGAR,

Thanks for the quick reply and Mr.Lee for a fantastic article.
Actually i was using proxy for SDk.Hence it was not working.
If i connect my sdk directly it is working fine.

Also for ppl who are facing same problem in SDK connected with proxy servers can try using your android phone(build ur app in debug mode using same procedures mentioned above) and im able to see the maps.

POSTED BY NEWBEE 4 YEARS AGO

Mr.Lee

The code for Geo coding is not working.I am not getting the address of a location that i had just touched.
please check once & send the correct code for Geo coding.

thanks in advance.

POSTED BY AATUL.PALIWAL 4 YEARS AGO

Hi;
I have developed the map application from the tutorial and it has build successfully. Now my problem is that when i am going to deploy the application into real device, its showing me the message: Application Not Installed

please help me.

Thanks in advance.

POSTED BY SAFADI909 4 YEARS AGO

hi, i had this problem with using maps in android

java.lang.IllegalAccessError: Class ref in pre-verified class resolved to unexpected implementation

i had attached maps.jar.

just check if u have another maps.jar then this jar which is loaded with google API.

POSTED BY MR_SPS 4 YEARS AGO

Hello weimenglee,

Thanks for the nice tutorial. It's really great. I am using your code in my project.

Now I have issue, when we do zoomIn/zoomOut that time location of Markers is not showing on place but when we stop zoomIn/zoomOut than it's show on current place.

I just want th change marker position with zoom [map controller on zoomIn and zoomOut]. Can you please give me an idea.

waiting for your responce.

POSTED BY MR_SPS 4 YEARS AGO

Hello ,

Can you please help me, I have put me code here..

The issue is, when we do zoomIn/zoomOut on map I want the pin position should not change. At any point of time the position of marker can't change it's location.

Here is my code:-

public class MapsActivity extends MapActivity
{
MapView mapView;
MapController mc;
GeoPoint p;

class MapOverlay extends com.google.android.maps.Overlay
{
@Override
public boolean draw(Canvas canvas, MapView mapView,
boolean shadow, long when)
{
super.draw(canvas, mapView, shadow);

//---translate the GeoPoint to screen pixels---
Point screenPts = new Point();
mapView.getProjection().toPixels(p, screenPts);
//mapView.getProjection().toPixels(p, screenPts);
//---add the marker---
Bitmap bmp = BitmapFactory.decodeResource(
getResources(), R.drawable.pin);
canvas.drawBitmap(bmp, screenPts.x, screenPts.y-50, null);
return true;
}

@Override
public boolean onTouchEvent(MotionEvent event, MapView mapView) {

if (event.getAction() == 1) {
p = mapView.getProjection().fromPixels((int) event.getX(), (int) event.getY());
mc.animateTo(p);
//listOfOverlays.add(this);
return true;
} else{
//this.draw(this.toString(), mapView,this.SHADOW_X_SKEW, this.SHADOW_Y_SCALE);
return false;
}

}
}
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

mapView = (MapView) findViewById(R.id.mapView);
LinearLayout zoomLayout = (LinearLayout)findViewById(R.id.zoom);
View zoomView = mapView.getZoomControls();

zoomLayout.addView(zoomView,
new LinearLayout.LayoutParams(
LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT));
mapView.displayZoomControls(true);

mc = mapView.getController();
String coordinates[] = {"1.352566007", "103.78921587"};
double lat = Double.parseDouble(coordinates[0]);
double lng = Double.parseDouble(coordinates[1]);

p = new GeoPoint(
(int) (lat * 1E6),
(int) (lng * 1E6));

mc.animateTo(p);
mc.setZoom(17);

//---Add a location marker---
MapOverlay mapOverlay = new MapOverlay();
List listOfOverlays = mapView.getOverlays();
listOfOverlays.clear();
listOfOverlays.add(mapOverlay);

mapView.invalidate();
}

@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
}

POSTED BY MAALI 4 YEARS AGO

Hej Wei-Meng

I tried this using Eclipse.
For some reason Eclipse does not read the "import com.google.android.maps" liberaries !!

What do I do wrong?

BR
Maali

POSTED BY DIDACGIL9 4 YEARS AGO

Once applications like this one are done, how is it possible to deploy in mobile phones that do not contain the Google APIs? Such as the HTC Hero.
It complains (even the logcat says nothing) about a missing com.google.android.maps library.

POSTED BY ASSEM.MOHSEN 4 YEARS AGO

to BR Maali

change your file AndroidManifest.xml like this:

POSTED BY KHAN 4 YEARS AGO

Thanks Mr. Lee for the wonderful tutorial...expect more tutorial from you on maps and location based services for android platform..a bit more explanation of the codes will be extremely useful..

POSTED BY DAVIDIZ 4 YEARS AGO

Thank you the tutorial is very well written. I do have one problem with the reversed geocode example. As far as I can determine the Try returns an exception relating to not connecting to google. My maps work so I know I have the correct apikey and permissions.
Is there something else I need from google to access the Geocode?

I think this is the last messages on the log:
02-11 15:59:12.848: WARN/InputReader(67): Touch device did not report support for X or Y axis!
02-11 15:59:24.678: DEBUG/SntpClient(67): request time failed: java.net.SocketException: Address family not supported by protocol

These are my imports:
import java.io.IOException;
import java.util.List;
import java.util.Locale;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Point;
import android.location.Address;
import android.location.Geocoder;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.Toast;
import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapController;
import com.google.android.maps.MapView;
import com.google.android.maps.MapView.LayoutParams;
import com.google.android.maps.Overlay;

Here is my code: (there are no errors)

@Override
public boolean onTouchEvent(MotionEvent event, MapView mapView)
{
//---when user lifts his finger---
if (event.getAction() == 1) {
GeoPoint p = mapView.getProjection().fromPixels(
(int) event.getX(),
(int) event.getY());

Geocoder geoCoder = new Geocoder(
getBaseContext(), Locale.getDefault());
try {
List addresses = geoCoder.getFromLocation(
p.getLatitudeE6() / 1E6,
p.getLongitudeE6() / 1E6, 1);

String add = "";
if (addresses.size() > 0)
{
for (int i=0; i i++)
add += addresses.get(0).getAddressLine(i) + "\n";
}
Toast.makeText(getBaseContext(), add, Toast.LENGTH_SHORT).show();
}
catch (IOException e) {
e.printStackTrace();

}
return true;
}
else
return false;
}
}

POSTED BY NISCHAL 4 YEARS AGO

hi ,

i am successful in displaying google map .

now i want to add "search" option to it .i.e the user can give a place name as input and our map should display that respective position

how can i do this ?

can anyone plz do guide me?

nischal

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