Question: Small Floating Window on Top of Everything

It's possible to create a transparent activity, holding a small panel inside, so it gives the effect that the application is a small floating window.

I'm not sure how to do the "always on top of everything" part, though.

hello,
thanks for the quick answer.
what I'm looking for is a small window or button which is floating on top of everything. for instance you can launch apps with your favorite launcher and can still see this little window with some information in it on top. you can do everything normally - only touching the small window brings up the underlying app. I thimk such windows are called "system overlays", but I'm not sure. (One is used in HoneyBar.)
best regards
Runner65