Mobile Application Development Some Real Life Practical Experience Words of Wisdom(?!) by Dave Westwater

A Few Admissions I'm self taught, so I don't know everything! Been 'out of it' for a couple of years now, not up-to-date. Mostly games development. 3 years embedded C, 6 years of J2ME, no experience of other languages.

Lessons Learned (1) First job in industry with Nokia ( ) First lesson learned: There's no big secret to mobile application development! Languages are essentially the same as those for desktop applications with some restrictions: C/C++/C#, J2ME,... Project life-cycles are essentially the same.

Lessons Learned (2) Second Lesson: Be acutely aware of the environment! Using very limited resources: Screen size, processing power, memory (both flash-ROM and RAM), user interface, connectivity Can you write a game engine plus four games in <90kb? Better now of course. You've got it easy

Lessons Learned (3) Third Lesson: Optimise, optimise and optimise again... Particularly true in games programming Pushing the phone to the limit of CPU power and memory usage. You want to use every available resource. Comes with experience. A good book should give you helpful hints.

Lessons Learned (4) Second job in industry: 3G-Scene ( ) First real use of J2ME, first mobile casino Fourth Lesson: One instruction manual, twenty interpretations Sun release the JSR descriptions of APIs. Can be vague in places Manufacturers seem to have their own interpretation. Manufacturers and service providers drive JSR development

Lessons Learned (5) Fifth Lesson: Phone software is full of bugs. Not surprising! First in a new line is always the worst. Need to work around some problems Examples Samsung D500, HTTPConnection always fails when first opened, need to close then reopen it. Nokia 6600 series, early versions had problems with full screen mode

Lessons Learned (6) Sixth Lesson: Brute force testing on the device is the only assured way of ensuring the apps work on the phones! You can develop on emulators and it will work fine. Put it on a phone, it will fall over. Stems from lessons 4 and 5. Emulators are getting better. Nokia's S40 emulators were very good.

Lessons Learned (7) Seventh Lesson Debugging on the device is a bitch! No stdout or stderr stream for error output. Need to draw on the screen. In J2ME throw up alerts with the information. Do as much as you can on the emulator! Fail gracefully Nothing worse than having to remove the battery to reset the phone when an app crashes.

Lessons Learned (8) Eighth Lesson: Make the product work. You can't issue patches to fix the problem. Need to reissue the whole application. MIDP3 going to use shared libraries A consumer will be annoyed if they purchase an app that doesn't work. Not restricted to mobile apps.

Lessons Learned (9) Third job in industry: Tricast Solutions ( ), J2ME engine for flash-like media Ninth Lesson: Don't use a high-end phone as your baseline! You'll need two baseline phones for each screen size template One with lowest CPU power One with smallest memory Find the most restrictive devices you want your app on and do them first.

Lessons Learned (10) I tried hard to think of another one but couldn't. I could give lots more technical advice but I've kept this as general as possible.

Lessons Learned (10) I tried hard to think of another one but couldn't. I could give lots more technical advice but I've kept this as general as possible. Be prepared to do lots of porting! More porting. Less developing.

Some Links J2ME API documents: Community: Distribution: free, and it's not all sex.

Examples Demo games: Source code to be added to course website. Might be old code I hope it works!