Substance of Code » Java

Babel Fish for Twitter – New Twim Release

Tommi Laukkanen — Mon, 02 Nov 2009 20:56:00 +0000

Google Translator is a great translator tool which has a very simple AJAX API that can be easily used from mobile apps. Compared to other translator tools it has one feature which other services don’t have, the auto detection of language.

The API is really easy to use. All you need to do is to pass three parameters to the API call:

Version, v=1.0
Translated text, q=Hei maailma!
Language pair (if source is empty then language is automatically identified), langpair=|en

In the end you end up with the following URL:

http://ajax.googleapis.com/ajax/services/language/translate?v=1.0&langpair=|en&q=Hei+maailma!

And if you click the link you’ll see that it returns the translated text in JSON format which is pretty easy to parse.

{ "responseData": {
"translatedText":"Hello world!",
"detectedSourceLanguage":"fi" },
"responseDetails": null,
"responseStatus": 200}

This made it pretty easy to integrate the API call to Twim. So now in Twim 1.6 you can select a tweet from status list and select “Translate to English” from status menu and Twim will display the translation to you in seconds. Pretty handy if you are following people from other countries in Twitter. Go ahead and download the latest Twim to your mobile phone from here.

…and by the way, new feature also has the “paging” feature for home screen and search results as a bonus! Happy Twittering!

Twim 1.15 with Auto-Refresh and TwitrPix Support

Tommi Laukkanen — Sat, 22 Aug 2009 10:49:52 +0000

Just finished testing the latest version of Twim, v1.15. Now you can also send your photos to new TwitrPix service.

I also added few options that you can configure via settings view. You can set Twim to automatically load the home screen tweets when application is started and you can also turn on the auto-refresh option that will automatically load new tweets in every 5 minutes. If new tweets are found then phone vibrates and plays a small beep sound. With this feature you won’t miss a single tweet again :)

New settings view

Full release notes:

TwitrPix support
Cancel option to media menu
Initial auto-refresh option with alarming of new tweets
Option to automatically load tweets on startup
Tab names changed: “Recent”>”Home”, “Friends”>”Following”
Fix for non-latin characters when posting photos (thanks Lexa!)

Have fun with the new Twim and download it from here. If you like the source code you can see that in here. Twim is still free as a free beer.

In case you didn’t know: Twim is a mobile Twitter client. I’m twittering with username @tlaukkanen.

Coding Touchscreen Scrolling in Java ME

Tommi Laukkanen — Wed, 29 Jul 2009 20:27:38 +0000

Here’s the trick how you can add touchscreen scrolling to your J2ME applications. The key to touchscreen support is the Canvas class and its’ methods pointerPressed, pointerDragged and pointerReleased. These events are called when user puts finger on the screen (pressed) and drags the finger (dragged) and finally when removes the finger (released). Each method has the x and y coordinates for the pointer action.

The scrolling is implemented with the pointerDragged event. We store the current location of the canvas to variables verticalLoc and horizontalLoc. When finger (pointer) is dragged then location is changed according to the dragged amount. Variables are used on paint method to draw the area so that it is scrolled that correctly. You can also see from the sample code how you can draw background with repeatable pattern image.

public class ScrollingCanvas extends Canvas {
// Current location
private int verticalLoc, horizontalLoc;
// Last pointer (finger) location
private int lastX, lastY;
// Background image size
private static final int IMAGE_WIDTH = 183;
private static final int IMAGE_HEIGHT = 183;
public ScrollingCanvas() {
verticalLoc = 0;
horizontalLoc = 0;
setFullScreenMode(true);
}
protected void paint(Graphics g) {
// Draw background with pattern image
int x = horizontalLoc % IMAGE_WIDTH;
if(x>0) {
x -= IMAGE_WIDTH;
}
int origX = x;
int y = verticalLoc % IMAGE_HEIGHT;
if(y>0) {
y -= IMAGE_HEIGHT;
}
boolean verticalDone = false;
while(!verticalDone) {
boolean horizontalDone = false;
while(!horizontalDone) {
g.drawImage(
ImageRepository.getBackground(),
x, y, Graphics.LEFT|Graphics.TOP);
x += IMAGE_WIDTH;
if(x>getWidth()) {
horizontalDone = true;
}
}
x = origX;
y += IMAGE_HEIGHT;
if(y>getHeight()) {
verticalDone = true;
}
}
}
/**
* Finger is pressed on screen
* @param x coordinate
* @param y coordinate
*/
protected void pointerPressed(int x, int y) {
lastX = x;
lastY = y;
}
/**
* Finger is dragged on screen
* @param x coordinate
* @param y coordinate
*/
protected void pointerDragged(int x, int y) {
// Calculate how much we moved horizontally
int deltaHorizontal = lastX – x;
horizontalLoc -= deltaHorizontal;
lastX = x;
// Calculate how much we moved vertically
int deltaVertical = lastY – y;
verticalLoc -= deltaVertical;
lastY = y;
// Repaint the screen since we have scrolled
repaint();
}
}

Here is a video of running this demonstration app in Nokia N97 SDK emulator:

Learning the git, Mobidentica now Open Source

Tommi Laukkanen — Tue, 24 Mar 2009 19:53:38 +0000

I’m learning to use the git, distributed version control system. It seems to be much faster then Subversion that I have used with my Google Code projects. I just created a repository on GitHub for Mobidentica project. Source code is available under the Apache License 2.0. If you like to clone the repository, use this:

git clone git://github.com/tlaukkanen/mobidentica.git

I’ll have to see if I’ll start using git with those projects that are on Google Code as it seems to be possible too: Benjamin Lynn from Google Developer Programs wrote a blog post on how to use git on Google Code projects.

Optimizing Trail Recording

Tommi Laukkanen — Sun, 22 Mar 2009 19:09:51 +0000

I coded a prototype how we could record fewer GPS positions in Mobile Trail Explorer and therefore save some memory but still have the same level of detail of the trail. Video might explain it best. Unoptimized recording is on the left and optimized trail is on the right.

The algorithm simply checks if the current direction have changed since last recorded position. If direction isn’t changed over the tolerance value then we can replace the last position with current position. Otherwise we only append the new position to the trail.

public boolean canRemovePreviousPosition(
Vector positions,
GpsPosition pos1) {
if(positions.size()<2) {
return false;
}
GpsPosition pos2 = positions.elementAt(
positions.size()-2 );
GpsPosition pos3 = positions.elementAt(
positions.size()-1 );
// Calculate last angle of trail
double latDelta = pos2.lat – pos3.lat;
double lonDelta = pos2.lon – pos3.lon;
double lastAngle = Math.atan(latDelta/lonDelta);
// Calculate current angle
double latDelta2 = pos3.lat – pos1.lat;
double lonDelta2 = pos3.lon – pos1.lon;
double currentAngle =
Math.atan(latDelta2/lonDelta2);
// Get absolute value of direction change
double angleDelta =
Math.abs(lastAngle – currentAngle);
// Check the tolerance (0.105 radians = 6 degrees)
if(angleDelta>0.105) {
return false;
} else {
return true;
}
}

Nokia E71 and new Twitter client

Tommi Laukkanen — Sat, 13 Sep 2008 12:54:12 +0000

I finally upgraded my phone from N80 to E71. The new Nokia E71 is a really nice. Even the Symbian S60 feels much better now that the phone has enough memory to run it. Operating system still has not changed that much compared to my first smart phone, Nokia 7650 which I had in 2002. This phone is still the best one I have ever had. Even Joel Spolsky is using it.

Twitter Client Twim running on Nokia E71

The new phone got me inspired to improve my Twitter client, Twim. I fixed a few bugs like showing the replies feed. I also added a new feature for displaying public feed in own tab. You can download the JAR and JAD files from the Twim page or directly from these links:

Twim v1.2: Twim.jar and Twim.jad

Mobile Trail Explorer v1.12 Released

Tommi Laukkanen — Wed, 13 Aug 2008 21:06:08 +0000

It’s only handful of days since last release, but I decided to release the v1.12 so soon as the v1.11 contained few bugs that were blocking few critical features, like adding a new waypoint and changing display settings.

You can download the new release from here or here. New version also contains a new languages, French and Dutch. You can now also change the language if you want to use other then phone default language. Thanks for the contributions and test reports reported on Google Groups discussions.

Mobile Trail Explorer v1.11

Tommi Laukkanen — Tue, 05 Aug 2008 20:16:24 +0000

Here it is, a new release of Mobile Trail Explorer. Here are the release notes for this release:

Renamed “Waypoints” to “Places” (Issue 92)
Filename uses datestamp with seconds
User can add audio-markers
Configurable action keys (# and * keys)
New speedometer screen (Issue 112)
Support different grid formats (Contributed by Kaspar Mösinger)
Encoding problems with KML import (Issue 120, Contribution from Bastian)
Translations to German, (partial) Finnish and default English (Thanks to Patrick)
…Plus tens of bug fixes and smaller features

Big thanks goes to all contributors and the “core” dev team as well.

You can download the latest binaries either from Google Code project page or from the Trail Explorer page, here. Report any bugs or ideas on the Google Group.

Drawing scalable numbers with J2ME

Tommi Laukkanen — Thu, 31 Jul 2008 18:15:39 +0000

One of the users suggested that Mobile Trail Explorer (MTE) should have a speedometer screen which shows current speed with large numbers so that it could be used as a normal speedometer while driving a bike. One of the challenges is that MTE runs on different devices and therefore on different screen resolutions. For example my Nokia N80 has a very large resolution of 352 x 416 while latest N series devices are usually running with 240 x 320 and older devices are using smaller 176 x 208 resolution.

Using the bitmap fonts would have been a solution but that would require us to store bitmaps for every resolution and that would eat up a lot of valuable memory. I have used bitmaps fonts on SubOthello game. I think that it suits really well for mobile games which are targeted and built separately for different devices.

To solve this more generic way, I created a NumberArea class for, which This is used to draw an area into Canvas where numbers such as speed and distance are rendered with basic Graphic methods such as fillRect(…) and fillRoundRect(…). If you are interested you can take a look into a source code.

On a side note: We are now on feature freeze with MTE so that we can release the v1.11 within a week or so.

Thanks Atlassian

Tommi Laukkanen — Fri, 18 Jul 2008 21:22:29 +0000

It was a nice suprise to find Atlassian’s Codegeist T-shirt from my mailbox the other day. This year I was only able to code a small plugin for JIRA called NetBeans JIRA Plugin. I got the idea for this plugin as I was reading a book, Rich Client Programming, which has a great value when you are programming rich desktop apps or plugins for NetBeans platform.

Atlassian Codegeist T-Shirt

The plugin uses JIRA’s Web Service API to search, view and edit issues straight from the IDE. This is especially handy when you are writing a code to a specific issue and want to check some details or log work done for the issue.

The Atlassian Codegeist is a competition where everyone can write plugins for Atlassian products, such as JIRA, Bamboo, Confluence, FishEye, Crucible etc. I use those tools daily at work and I can truly say that they really improve the daily development process signifigantly.