What SDK for multi-platform app?

What platforms do you want to support?

well ideally iphone, android and tablets at minimum. Then possibly blackberry/windows phone depending on if they have enough marketshare to be worth it.

I've been looking into Rhomobile/Rhodes. It seems like you write your app in HTML5 and then it works some magic to make it look like a native app. I believe this means it has to have internet access and connect to a server.

I'm wondering if anyone has used this technology and can report if there are any downfalls as to writing a native app.

Thanks

I recommend you the Marmalade (C++). It has 90-day trial period, which allows you understand all features.
I think that it is one of the best SDK for game development.

I'm making a html5 game right now and I'd honestly go DOM if I did it again(half of it is DOM, just plain divs/jquery and some sprite sheets, but much the gameplay is in the canvas), but for 2d games it's really simple and cross browser/platform....I think DOM is faster than the html5 canvas, overall. I'd check isogenic engine if it suits your project but it's definitely not needed. It uses DOM rather than html5. It uses node.js for multiplayer, you can use node.js and socket io from notepad by yourself.

If I was rich I'd buy unity licenses but this has been a great free way to develop for phones/ipad. Also multiplayer in html5/DOM is pretty slick and localstorage lets you persist data on mobiles super easy from the browser. It's really nice to have games on the webpage and not require plugins to play it as well, javascript is awesome and more powerful than I ever thought.

There's an excellent interactive list of mobile frameworks here.

Have a look at HaXe and NME http://haxenme.org

Nice, simple AS3-like syntax and libraries and can compile natively to:

Flash Player,
iOS,
Android,
WebOS,
HTML5,
Windows,
Linux

No windows phone yet tho :/

If you're looking for 2D and Flash-like cross-platform for mobile devices, I believe the options are

Corona SDK : uses Lua as the scripting language
AGK: "Tier 1" uses a BASIC-like scripting language.
Neither of which is free, but both are relatively inexpensive.
Also Haxe which someone posted above, which is free.

Or HTML5 + javascript, but to sell in the AppStore you need to create a shell application for each platform that creates a WebView GUI control and then lauches your HTML into that.

For C++, the all inclusive options are Marmalade or AGK Tier 2. Both are not free, and Marmalade is probably the better choice, imho. Beyond that, in the C++ mobile cross-platform free but not all-inclusive category, I believe, SDL can be used on iOS and Android (someone correct me if I'm wrong about that).

Be aware though, selling anything in the Apple AppStore involves buying a Macintosh if you don't have one and want to be legal about it. Also be aware -- and this is seriously just my opinion -- but a lot of these things look like they violate Apple's developer aggreement, e.g. Corona, which could cause problems in the future.

These are things I have used and recommend:

Unity3D - C#, Component Based, Easy deployment. Costs anywhere between $800-$4k.
Marmalade SDK - C++, Easy deployment. Costs $100\Per Annum
Proton SDK - C++, Semi-Hard deployment, Component-Based. Costs $0 and you can get the full source code.

Depending on how much money you have would determine what to use.

I recommend you the Marmalade (C++). It has 90-day trial period, which allows you understand all features.
I think that it is one of the best SDK for game development.

BTW. Marmalade is the new name for the Airplay SDK.