I've released updates to all my apps in the past couple days. Too much coding! The plus side is my new checklist app, d2cchecklist, is complete and ready on the Market. This is the most complex app I've yet written, weighing in at ~5700 lines of Java code and comments (and that's after rewriting many sections at least once as I learned to do things the right way!)

This has been a great learning experience and I have lots more development tips to share, if there's interest. Some possibilities:...

There are several sites out there (like these) that show you how to use Android preferences, but I haven't seen anyone explain how to extend DialogPreference to get your own custom preference stored. I had to dig into the Android source to figure this out since reading Google's documentation on DialogPreference is like reading Greek!

I did this twice in Gas Mixer; once using my NumberSelector component I explained in my last posts, and also with my TrimixSelector. Because the TrimixSelector,...

This is a continuation from my last post. This gets into the complicated, annoying parts that are the result of some limitations in the Android framework.

Internal listeners
I'll omit most of the internals of my Button OnClickListener and TextWatcher implementations, except where there's something really strange going on. For instance, how I detect whether a value change came from the user or not (which I need to pass to my ValueChangedListener) is not easy.

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It was waaay too hard to figure all of this out, and I documented some of the solution on anddev.org, but it's pretty complex so I thought I'd lay it out step-by-step for how I built a real Spinner widget in Android.

I wanted to build a special widget class that would show an EditText and two buttons for entering numeric values. The two buttons would be plus and minus buttons, allowing the user to adjust the value in the box by a set increment. The box itself needed to have enforced...

I've been putting a lot of time into Gas Mixer lately! I released v 2.0 and followed it up today with 2.5.

2.0 was a nearly complete rewrite of the interface. I've removed the OpenIntents sliders and replaced them with Android SeekBars, color-coded for oxygen and helium. I also made lots of UI changes to avoid scrolling at all costs. I came to realize on a mobile platform it's just as inconvenient to have to navigate to a new screen as it is to scroll down on a long one. Support for...