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Tag: Android

I have finally started uploading apps to the Android app store. The three apps I previously wrote about (Scientific Name Search, Plasmatic and Dutch Public Holidays) are uploaded to the app store, as well as a few apps I created based on a version of my astronomical library ported to Java.

The crowning glory of these astronomical apps I have uploaded to the app store is Night Sky Tools (

The features included in the app are:

  • Angular separation
  • Astronomical Time
  • Atmospheric refraction
  • Coordinate convertor
  • Eclipses
  • Magnitude
  • Precession
  • Conjunctions and Oppositions
  • Ephemerides of the planets, sun and moon
  • Equinoxes
  • Positions of Jupiter’s moons
  • Planetary orbits
  • Constellations
  • Stellar Classification
  • Telescope Airy Disc
  • Telescope F-Ratio
  • Telescope Magnification

Go ahead and check out the app.


Recently I decided to experiment a bit more with developing Android applications. I had played around with Android a rather long while ago, creating two rather simple apps – Dutch Public Holidays and Plasmatic, but decided to look at it again.

I have improved upon my two previous apps, making them much more useful, and created a third app, using webservices to look up animal and plant scientific names.

Thanks to the thousands of Android tutorials littering the web, it is not hard at all to get started in Android development, and the integrated Eclipse/Android SDK makes for a very pleasurable development environment.

Since there is nothing that can’t be found in other tutorials in the applications, I won’t list the code for the apps themselves, but you can download the source code for the apps from the links below.

Dutch Public Holidays
This was the first app I wrote, and is rather very simple in construction. It merely shows a list of public holidays for the Netherlands for a particular year.

I ported some code from my C# fractal library I had written a while back to Java to draw plasma fractals. The application generates a plasma fractal based on a set of preferences, and is able to save the generated images to a file on the mobile device.

Scientific Name Search
This app makes use of a webservice provided by to search for information such as the scientific name and taxonimic classification of plants and animals.


A few days ago I blogged about my first Android app, and in that post I promised another one coming along soon. Well, it is now done.

For my second foray into Android application development, I decided to port some C# code I had previously written to draw a plasma fractal to Java.

A plasma fractal

A plasma fractal

The original code is based on a Java applet written by Justin Seyster, which I ported to C#, and modified slightly, a few years ago for another project.

I have previously blogged about the algorithm used to generate the plasma fractal itself in my series on Fractals in C#, so I won’t go into detail about how the fractal is generated here.

The application consists of three activies.

The main activity displays the generated plasma fractal, with menu options to refresh the fractal, which regenerates the fractal, and saving the image to the sdcard.

The menu also has options to launch the settings activity and the about activity.

The settings activity enables you to change the fractal type – the options being, Plasma, Cloud and Grayscale – as well as the roughness, which changes the amount of variation in the image.

The about activity merely showssome information about the application.

While, by no means, a complicated application, this app implements a fair amount of Androids basic features.

You can download the Plasmatic android package here


Having my own Android-based phone now, I have been unable to resist the temptation to try my hand at writing an app for it. Deciding on what app I should write, however, required a bit of thinking.

Firstly, if you have ever browsed the Android Market (and if you own an Android phone, no doubt you have), you will have noticed that it has literally hundreds of thousands of applications available for download (either free or for purchase), so finding an application idea that hasn’t been done a hundred times before becomes a bit of a challenge.

The second thing, is that my Java is a little bit on the rusty side. The last time I have written anything at all in Java was around 11 years ago, and even then my jaunt with Java was rather brief.

This means that to ease myself into the Java development environment of Android, I wanted to go with a relatively simple app, leaving more ambitious projects for later.

So, out of this, I came up with the Dutch Public Holidays app, which all it basically does is give you a dropdown of years (currently only 2011 and 2012), and then displaying the public holidays in the Netherlands for that particular year. Very, very simple!

The actual code of the app is largely based on the spinner tutorial on the Android Developer site, but instead of updating a toast, the application updates the TextView with the info we want, and I rearranged how some ofthe code worked.

If you would like to download the package for the app, I have uploaded it to this site.

Just run the package from your phone, and it should install fine. This package requires Android 2.1 or above to work.

I intend to write more apps to learn more about Android, and at some stage get my apps onto the Android Market, but that is something for another day…


I have had my new Samsung Galaxy for almost two weeks now, and it is the most incredible phone I have ever owned.

The best thing about the phone though, is the combination of GPS and accelerometer, which enables me to enjoy a wealth of really useful applications that make my phone seem like advanced technology compared to Star Trek communicators – I mean all they were good for was talking to their ship in orbit!

The Android market has hundreds of thousands of apps on it, and I have had fun trying a lot of them out.

I make liberal use of my gmail, twitter, linkedin apps, which provide nothing really new to my cellular experience, as I have been able to do that sort of thing for years on my phone. Most of my fun was had trying out the new toys I have never been able to do before.

Things like using the on-board camera to read barcodes is a really nice feature. There are apps that can find books on Amazon, or find prices on products by merely scanning the barcode.

Then, using the accelerometer, I have played with several planteriums (or is it planetaria?), which using the phone’s accelerometer shows you the section of the skymap at which your phone is currently pointing. This is a sheer astronomical delight.

And while I am talking about the accelerometer, other useful apps using this is a protractor, Smart Protractor that measures the angle at which the phone is lying, at long last giving me the means to check to see if the paintings in my lounge are really hung up straight or not.

A related app, Smart Measure uses the phones camera and angle-finding abilities to calculate the distance to a particular spot. It only works in a fairly short range, but cool none-the-less.

Moving on to the GPS apps, the phone ships standard with a full-on GPS navigation system, as well as Google Maps, meaning I never need a separate GPS unit again.

Using the GPS, augmented reality apps such as Layar are showing up. This uses the GPS, camera and accelerometer to inform you of nearby things of interest interactively. By simly moving your phone around, you can see the image through the camera, with the extra data overlaid over that, so as you move around you will what your camera is looking at, with whatever interesting items the app can show you in that direction.

Oh and did I mention that my phone can also make phone calls……


Over the weekend, my old Se Xperia X1 decided to seriusly give up the ghost, so I went out and got a new phone, and settled on the Samsung Galaxy S.

Ah, the just-bought-a-new-toy feeling!

It is one of the more reasonably priced phones, not quite competing with the big boys, but it is an awesome phone none-the-less.

This is my first experience on an Android phone, and I can sincerely say that it is the best cellular experience I have yet had with a phone. It far outshines any Windows Mobile or Symbian phone that I have used in the past in every category.

The phone responds quickly, has decent hardware, and ample storage space (well for me anyway).

I am really looking forward to playing around with this phone…


If you thought that you are stuck with using Windows Mobile with your Xperia X1, you would be wrong. Of course, the only officially supported operating system is Windows Mobile, but that doesn’t stop you from tinkering a little.

XDA-Developers have released a version of Google Android that works on the Xperia X1. It is still missing a few features, such as the GPS functionality, but it works well.

Also from XDA-Developers is a port of Ubuntu Hardy Heron 8.04 which gives you full-on Linux functionality on the X1.

It seems these days that we are fast heading to the days of being able to choose whichever OS we like to use on our phones, and that does make the future exciting!