You had your keystore file in your project's "Objects" folder? I thought that was the only folder affected by "Clean Project", but I could be mistaken. Regardless though, I wouldn't keep it in any project folder. I think I put mine in a subfolder of the main B4A folder, but you can put it anywhere that it would not get written over. Are you sure you didn't just forget which folder it was in? Wishful thinking......
But to answer your question, unless you happen to have a backup of it or have an OS that saves "old versions" of folders (such as XP Pro, etc), then I don't think there is any way to recover that file. Do you perhaps have a backup (zip) of your project folder & subfolders somewhere? I always backup the entire project folder and subfolders every time I release a new version of my app. That way I can always go back to any previous version for any reason and get the original code and APK back.
If you haven't actually published anything on the Market yet, I would just create a new one and point to that one in your projects. Oh, and MAKE A BACKUP OF IT. I have three backups of mine in various places.
If you
have published apps in the Market, then you will not be able to publish them as updates to the same app, but instead would have to consider them to be different apps (if I understand it correctly, that is).
Good luck!
