Help With Buttons and SetGravity

Physics
#1

I am new to Corona and just starting to learn it. I was trying to build a test app with my new-found knowledge of buttons, in which you press a button to toggle the gravity on a ball, but it doesn’t work and I have no idea why. Please Help. Thank you in advance!

Here is my code:

physics = require(“physics”)
widget = require(“widget”)
physics.start()

local gravSet = false;
physics.setGravity(0,0)

local bubble = display.newCircle(300,0,10,10)
physics.addBody(bubble)

function ToggleGravity()

if gravSet == true then
gravSet = false
gravBtn:setLabel(“Start”)

physics.setGravity(0,0)
print("Gravity Stopped!")

elseif gravSet == false then
gravSet = true
gravBtn:setLabel(“Stop”)

physics.setGravity(0,10)
print("Gravity Started!")

end

end

gravBtn = widget.newButton({
label = “Start”,
width = 200,
height = 50,
top = 0,
left = 0,
defaultFile = “Buttons/Button1/default.png”,
overFile = “Buttons/Button1/over.png”,
onRelease = ToggleGravity
})

#2

Because to optimize the number of mathematical operations, bodies can fall asleep.
You can prevent this from happening globally by starting the physical engine with:

…

physics = require("physics")
widget = require("widget")
physics.start(true)

…

alternatively (and in my opinion it is better to do so) you can tell the individual object not to “fall asleep” with:

…

local bubble = display.newCircle(300,0,10,10)
physics.addBody(bubble)
bubble.isSleepingAllowed = false

…

Also consider that setting gravity to zero will not prevent your bubble from falling because at that point it will have an applied force and therefore you will see it fall anyway, if you want to stop it you will also have to cancel the applied forces by calling the setLinearVelocity function.

…

physics.setGravity(0,0)
print("Gravity Stopped!")
bubble:setLinearVelocity(0,0)

…

bye.

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