Well...I have a problem:
i would like to update my extension because it seems don't working on all devices...
but when i reopen it in Android studio it tell me: "Cannot resolve symbol 'appinventor'"
do you know what is the trouble ?
Are you opening directly with the code editor or manually opening it? It happens for me to, I just open it by clicking on the java file.
I open Android studio and then File->Open...
and the problem exist on both extensions I open !
You have to set up the classpaths correctly for Android Studio to locate the necessary classes. If you're using the extension repository, then you should make sure all of the libs in lib/appinventor are included.
Well i'm completly lost... 
I made my first extension for AI on Android studio (AS) , but I can't remember wher i found the way to configure it...and it seems AS configuration changed because when i open my project it can't recognize AI package...
but i'm not fluent enougth on AS to reconfigure it ...and to import AI package !
Can you let us know whether you're building using the appinventor-sources repo or using the extension template? From there we might be able to give you some advice.
I have appinventor-sources files on my computer. so it seems i used it !
i'm really sorry: when I wrote my extension I ffound a tuto explaining step by step how to start...but i can't find it any more !
AI files are on "C:\Users\Jml\appinventor-sources" in my computer but I don't know what I have tot typehere to import library...
or maybe it would be better to complete that but how ?
Oh I remind now !
When i wrote my first extension, I started with this tuto:
file:///D:/Documents/programmation/Android/telephone/TUTOS/faire%20une%20extension%20AppInventor/Extensions%20App%20inventor%202%20Create%20Extensions%20Tutorial%20Build%20extensions%20tutorial%20easy.htm
so I wrote it with a text editor. and I had a copy in Android studio in order to check there is no type mistakes...it was very boring to use both...
is there no way to use only Android studio (including AI package or other ..) ?