Event.ENTER_FRAME is called once for every frame Gideros runs. If you were to run the above code without it, it would just run through the code once, the ball will move ,and then the ball will cease to move. a example of enterframe usage (see #6)
Why do I need to use Event.ENTER_FRAME here in Gideros?
题
local W = application:getLogicalWidth()
local H = application:getLogicalHeight()
local xD, yD, speed = 1, 1, 10
local img = newImage("myImage2.png", 0, 0)
local wd, ht = img:getWidth(), img:getHeight()
function onEnterFrame(event)
local xP, yP = img:getPosition()
xP = xP + xD*speed yP = yP + yD*speed
if xP >= W-wd or xP == 0 then
xD = −xD
end
if yP >= H-ht or yP == 0 then
yD = −yD
end
img:setPosition(xP, yP)
end
img:addEventListener(Event.ENTER_FRAME, onEnterFrame)
I have above piece of code and my question is why Event.ENTER_FRAME
here? All this code does is move the ball across screen, we are not changing any frame,then why do I need this? What is the difference if I use it without Event.ENTER_FRAME
?
解决方案
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