I’m trying to get into and understand J2ME and I’m finding it pretty difficult to find information on the system. I was wondering if anyone could give me some answers on my multitude of questions…
I’d been informed that its best to target at MIDP1.0 since there arn’t many MIDP2.0 handsets. Is this really the case anymore?
Is it possible to play sound with MIDP 1.0 purely?
Are there any tutorials / starting out bits and pieces around anywhere?
Is there a facility/forum to get your games tests on a multitude of handsets or is just a matter of downloading every emulator you can find and running it through?
How big should a jar get? Originally I though the limit should be about 32k (some older handsets). But then I find most recent games are way above that, mostly above 200k!. Is there a guideline for this?
PNG Transparency support - can I assume that modern handsets have this even if the spec doesn’t require it? (Ok, ok, never assume anything).
Is there a feeling for whether mobile games players upgrade often?
Are there any other regular frequented generic J2ME forums/resource sites? I’ve noted the Nokia forums are quite popular.
Thanks for any help and apologies for the extended post.
MIDP 2.0 phones are becoming a lot more common - any new phone that comes out will be MIDP 2.0. But there are still a lot of MIDP 1.0 devices out there, and it will be at least a couple of years before they can be fazed out from commercial deployments.
No. The only thing that makes sounds in MIDP 1.0 is the AlertType.playSound() method that may or may not play an assortment of beeps.
Plenty. I’m guessing this is what you found in the Content Sites post.
Emulators can’t be trusted. getjar.com have a very nice beta-testing process.
Depends on the target phone. A nice number is 64K, since this is a very common limit on the older MIDP 1.0 phones (all of Nokia’s Series 40 1.0 phones have this limit, and they have the lion’s share of the market). Many operator’s have additional limits of their own for the size of downloads. Commercially you usually make more than one version and they don’t all have to be the same size (a version for a higher end phone with a bigger screen will need more resources, so it will usually be bigger).
Assume away. In all my two years in the field I’ve only seen one phone that didn’t support transparency (the Motorola i85, I think it’s the first actual J2ME phone in history).
Most manufacturer’s will have forums that are the best place to ask for issues with their handsets. The Nokia forum gets a lot of traffic (plenty of newbs though). There are also the sun forum’s (in the “J2ME Technologies” section), j2me.org, mobilegd.com’s forums, etc. And the KVM-Interest mailing list is also good. Apart from KVM-Interest and some of the manufacturer’s site’s it usually the same people.
