Figuring out appmaking will take a while, but it will be done!
In the meantime I'm working on a desktop calculator which will work in a similar manner as the app.
Here's some details:
Today I changed the web calculator to get the fuels from the text file at http://ttower.dyndns.org/boilerCalculator/fuel.txt
Besides making it easier for me to add new fuels this file is going to be shared between the web calculator, the desktop calculator and the app.
The desktop calculator and the app will download the file on first run and store it locally. The next time they are started they will compare the local version to the online version if possible and if the online version is higher they will re-download it.
If there is no internet connection, the server is down or updates are disabled through settings it will skip the check and just use the local list.
There may be support for third party lists either replacing or supplementing the official one. URL's to these would be added to a list in the settings.
This is what I've got so far! Comments, thoughts & suggestions are welcome!