Mobile phone lessons

I've worked on MyCollection for over a year now and there are some lessons I have learned while developing applications for the mobile phone:

1. Network connection is shaky at best
2. Application run-time is never guaranteed, expect nothing to be there
3. Users want the kitchen sink
   
4. Phone processing power varies greatly (at least on Android)
5. Pushing as much processing needs off to an external device (server, etc) helps performance
6. Minimize data transferred over radio

Lesson 1, I learned that cell-phone reception where a data connection is more sparse than phone coverage. My app needed to handle no data connection better.

Lesson 2: Android cleans up a lot behind the scenes. When users launched the external extent for barcode scanning, my app got killed sometimes. Handling this is tricky and I'm still not sure I got it right.

Lesson 3: I get so many feature requests it's not funny. Most of them make a lot of sense but would grow the application beyond what I think it should be. If you give the users the kitchen sink, its hard to keep the UI simple and performance good. Maybe I'll take all their suggestions and build a suite of applications some day when I'm 100% recovered...

Lesson 4/5/6: Parsing XML on the phone sucks. No simple way around it. Downloading a large XML document from Amazon and then making extra network calls based on what was in the document stinks. This is not enterprise programming... What I ended up doing was writing a REST service that returned a CSV file. XML is just to expensive over non-3G speeds which is still common for Android phones right now. The service I wrote checks Amazon and Google's GBase and parses the XML for the phone. It returns the results as a CSV file with a content type of plain text which is about as small as I can make the data transfer over the radio.