src.icon_state = "Fly"
src.icon_state = ""

Problem description:
Hello everyone. I want to create that when user stop flying he start to floats.
The first gravity code I ever used was the 1 in this link: Response #1

The sleep() that is used in the code controls how slowly they will fall from the gravity effect. Try using this gravity proc, it worked for me when I used it.
How do you know he is doing a platformer, Zerok Kaiba?

This question is too vague to be answered without guessing. We need more information, LaNuiit. It sounds like you give us some code and tell us what you want, like you expect us to do it for you. That is not what we are here for. We are here to help and guide you, not make your game for you. Now, provide all relevant code and tell us what the problem is so we can help you.
Like i sad ... i just want to code that when player move it flips his icon into a fly else if mob stoped moving it will use flyeffect proc
Well the suggestion I made works for a sidescroller game. Albro1 is right I just guessed you were using a sidescroller. Basically what you are asking for is how to make the flyeffect proc. We need to know what format you are using such as sidescroller, isometric, standard 3D, etc.
LaNuiit, read my post again. Don't tell us what you want us to do. We wont do it. Ask a question, and we will answer it.
You could give the icon_states for "flying" and "floating" the same name, but mark the "flying" state as a movement state. You haven't explained what the FlyEffect() process does, but if you want it to run when the player stops moving, you'll have to spawn a loop somewhere and track a boolean for whether or not they're moving.