One application for different android SDKs

Any suggestion/idea to develop one application for different android SDKs that users are using?? There are many different android SDKs. Thx.

It depends on what type of app your trying to make... If your not using any of the new features of the later sdk's then mostly you only have to worry about screen sizes. Android has built in support for working with different screen sizes. http://developer.android.com/guide/practices/compatibility.html

any difference between sdk version 2.2 & 3.0above for screen size/orientation change ? if only using sdk version 2.2 to develop one application, izzit able to handle all screen size/orientation change for all SDKs (tablets & phones)? Thx

Here's the guide for developing for 3.0: http://developer.android.com/guide/practices/optimizing-for-3.0.html

Also the android market now allows for multiple .apks to be uploaded for each app. So it is possible to write a whole new apk for each api level if you wanted to.