My name is Alessandro La Rosa, and I'm a freelance software architect for Mobile and Web platforms. I'm living in Rome, Italy.
Feel free to contact me at: info@jappit.com
I finally found some time to finish and publish the first release of a tiny library that allow to easily integrate Google Maps in every J2ME application: MidMaps.
You can read all the details, download the library together with sample code, and read the full JavaDocs here: MidMaps – J2ME Google Maps library.
I’m really honored that another article, published on Forum Nokia Wiki, has been selected as Article of the Month!
As the previous one, this also is related to Google Maps usage in mobile applications, and you can read it here: How to use Google Maps data in mobile applications.
As its name says, It’s an introductory article on how to use Google Maps services, in particular the geocoding and static maps ones, from a mobile application, where standard Google Maps API code is not suitable (since it is thought for web based and Ajax’d apps). Its content does not focus on any particular programming language, but gives base guidelines to use those services using REST.
So… any kind of feedbacks is welcome! 
I’m really happy to announce that my J2ME Google Maps API article on Forum Nokia Wiki has been selected 
as Article of the Week!
And, to celebrate this event, I’ve added a brand new feature to my article that will allow you to:
You start instantiating a GoogleMaps object as usual:
GoogleMaps gMap = new GoogleMaps("API_KEY"); |
Then you get your map, for example geocoding a given address:
double[] coords = gMap.geocodeAddress("Leicester square, London"); Image mapImage = gMap.retrieveStaticImage( 150, 150, coords[0], coords[1], 12, "png" ); |
Then, let’s say you want to scroll your map 100 pixels up, what you’ll do is:
double[] newCoords = gMap.adjust( coords[0], coords[1], 0, -100, 12 ); Image newMapImage = gMap.retrieveStaticImage( 150, 150, newCoords[0], newCoords[1], 12, "png" ); |
As you’ve seen, the adjust method takes these arguments:
and returns the new map center latitude and longitude coordinates.
You can check the full updated source code on Forum Nokia Wiki article: J2ME Google Maps API, and a full-featured example, with the scrolling feature, on the emulator page: J2ME Google Maps API in action.
I have a flash website
i’m looking for the script who of google adsense with flash.
can you give me the link?
Is there a zip file which has the .jar , .jad and .java file that i could try on J2Me wireless tool kit. I am a j2me beginner
I am trying to use adjust function for scrolling tiles, and i think that its inaccurate, i cant get two tiles match correctly
Note: You can find this article also on Forum Nokia Wiki: How to use Google Maps data in mobile applications
Today we’ll see how to use Google Maps data within a mobile application.
Google Maps offers REST services that allows accessing its data with simple HTTP requests, so we can easily integrate them within our mobile apps.
First thing you must do is to signup on this page:
http://code.google.com/apis/maps/signup.html
Once done, you’ll get a key (a simple String) you’ll use for all your query to Google Maps services
Standard Google Maps code is suited for web applications, since it includes alot of Ajax functionalities, that are not really useful if you’re building a mobile application. So, the solution is to use static maps service, that will allow us to retrieve single images, easily usable within our apps.
Static maps service supports different image formats (png32, gif, jpg) and customizable image size, so that we can get perfect images for all our needs. As an example, suppose we want to retrieve the location at:
We can simply retrieve this URL with an HTTP GET request:
http://maps.google.com/staticmap?center=41.867878,12.471516& format=png32&zoom=8&size=240x320&key=<API_KEY>
This way, we’ll get a PNG32 image, with a width of 240 pixels, and a height of 320, centered at point (41.867878,12.471516), and with a zoom level of 8 (zoom can go from 0 to a maximum level of 19).
From Google Maps docs:
Geocoding is the process of converting addresses (like “1600 Amphitheatre Parkway, Mountain View, CA”) into geographic coordinates (like latitude 37.423021 and longitude -122.083739)
So, let’s assume we want to build an application that displays the address typed by our user. We should firstly geocode its address to geographics coordinates.
To do this, Google Maps offer another REST service easily accessible with simple HTTP requests.
Let’s say you want to geocode this address “Leicester Square, London”, then you’ll request this URL:
http://maps.google.com/maps/geo?q=Leicester%20Square,%20London &output=csv&key=<API_KEY>
and you’ll get this output:
200,6,51.510605,-0.130728
Where:
As you can see, there is an ‘output’ parameter within the geocode request, and this means that we can choose the output format we prefer for our needs. Supported formats are:
Since your Google Maps API key is bound to a specific URL, to access map services you should setup a proxy server that will receive HTTP requests from your mobile application and forward them to Google Maps REST URLs, giving back Google responses to mobile clients.
Also, be aware that there is a limit to the number of requests (both for static maps and geocode service) you can do each day. For personal uses they’re more than enough, anyway consider this point if you plan to develop commercial services.
Now, you want code right? Here it is:
Hi!
I’m trying to execute the code you posted on the Forum Nokia Wiki. I use the Sun Wireless Toolkit and the EsclipseME IDE.
I get the following exception when invoking the retrieveStaticImage method:
java.lang.IllegalArgumentException:
at javax.microedition.lcdui.ImmutableImage.(+11)
at javax.microedition.lcdui.Image.createImage(+40)
at GoogleMaps.retrieveStaticImage(+28)
…
could you help me?
thanks a lot,
francesco
Hi Francesco,
this has probably something to do with illegal/corrupt data coming from server. If you try getting the map URL directly in your browser, does it work?
Also, which format are you using for your static maps?
Pit
Hi Pit,
thanks for your fast answer. I tried to change the format for the static map to png16 (I was using png32) and it works 
Now I have a problem with displaying the image: I can see just the first few pixels while the rest of the screen is black (width is alright, while the problem is with the height)
My code is pretty simple:
Image map = gMap.retrieveStaticImage(320, 240, lanLng[0], lanLng[1], 15, “png16″);
Form f = new Form(“Image”);
f.append(map);
display.setCurrent(f);
It is my first approach to midlets and I don’t really know what’s wrong. I also trying using canvas but I get the same result. Do you have any suggestion?
thanks again,
francesco
Hi Francesco,
sorry for the delay of my answer, but I totally missed your reply… :-/
Anyway, do you have this problem on emulators, or on real devices?
Pit
Hi,
Please I need help in finding a source code for designing a map on mobile application, I intend using a scanned image for the map.
Hi,
I’ve run into the same problem as Francesco. Only the first 50 or so pixels of the image from the top going down loads. This is in the emulator. Any thoughts on what may be happening would be much appreciated.
Thanks for the great guide.
Try to use DataInputStream() and readFully(). That solved my problems which were the same like yours – approximately 50pix of the image were displayed on the screen. Hope it helps. 
i want to geocode in my midlet application can any one help me
Hello,
Can you explain more the DataInputStream() and readFully() version?
I replaced the InputStream() with DataInputStream() instead. I don’t understand how to use the readFully().Can you post the altered code like the examples above?
I have the same problem with the black piece of the image. Thanks in advance.
Nevermind. My mistake. Found it. Thanks a lot guys!
Hello guys!!
Guzzler, can you tell us what was your problem, please??? Im gettin a NullPointerException. I changed as Francesco said to png16 but it doesn’t work for me. As the matter of fact I can get the image by the URL in the browser, but not in code.
Please can anybody help me out???
Hi Ernesto,
Did you find a solution to your problem even i get the same exception …
startApp threw an Exception
java.lang.NullPointerException
Please help me to solve this problem…
Ciao jappit,
sto usando la tua ottima classe “GoogleMaps” del forum nokia per delle prove con J2ME, funziona tutto ma solo se tolgo tutte le var double e le sostituisco con int, altrimenti mi da un “Error preverifying class GoogleMaps”. sai indirizzarmi verso la soluzione del problema? come faccio riconoscere i double a J2ME? te ne sarei molto grato, grazie ^_^
vfede
Hello All;
I am Developing an Application to get current location on googleMap for that i got Api Key.
I am developing this application on wtk & eclipse Ganymede. I am getting Exception
java.lang.ArrayIndexOutOfBoundsException
at AT.RetrieveLocation.checkLocation(+288)
at AT.RetrieveLocation.run(+12)
thanks in Advance
Dileep, 
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yama 10:05 am on April 22, 2010 Permalink
i am using your library.yours is a nice application but the only problem is that it shows path as a straight line instead of road to road view.please help me out with a solution that how should i show such road to road path in my application.Thanking you.
Nicholas Ndegwa 9:41 am on January 1, 2011 Permalink
Hi I like your API it works perfectly on the SUN emulator but does not work on the Nokia emulator nor Nokia device am getting the following error.
map error:1000, java.io.IOException: Error in
Umesh 7:45 am on March 15, 2011 Permalink
can we add important location like hotels,historical monuments, etc to static maps.
azura 4:01 pm on April 13, 2011 Permalink
thnks for share
i will practice it dude
Dileep 10:47 am on October 31, 2011 Permalink
i am used to your library. but It give the
java.lang.InstantiationException: Class not a MIDlet
at com.sun.midp.midlet.MIDletState.createMIDlet(+66)
at com.sun.midp.midlet.Selector.run(+22)
Unable to create MIDlet DisplayMap
How to i solve this problem.. Help me..