You have to set a callback function for pd.keyboard.keyboardWillHideCallback
(it is not a boolean property). This function will be called when before the keyboard hide animation begins.
function willHideCallback()
scene = "main"
main_init()
animation = {pd.keyboard.text, {gfx.image.new(400, 240, white)}}
end
pd.keyboard.keyboardWillHideCallback = willHideCallback