ansca-corona-102.pdf

Corona

www.anscamobile.com

What’s Corona

A simple, yet powerful framework allowing rapid

mobile cross platform application development.

Corona 102

Functions &

EventListeners

Corona framework based on Lua

Corona Lua resources

http://ww.lua.org http://www.lua.org/lua-l.html http://developer.anscamobile.com/

http://en.wikipedia.org/wiki/Lua_

Corona Without functions

local text = display.newText("hello",100,200,"Helvetica",24);

textObj:setTextColor(r,g,b);

Disadvantages:

When program begins to get too big, difficult to manage code

reusing code becomes hard to break apart

debugging becomes a nightmare

no sense of where program starts

Corona With Functions:

local function STextColor(textObj, r,g,b)

textObj:setTextColor(r,g,b);

end

local function main()

local text = display.newText("hello",100,200,"Helvetica",24);

STxtColor(text,255,0,0);

end

main()

Advantages:

easier to manage code

easier to re-use code on other programs as well

easier to debug since you can narrow down where error occurs

a sense of where program starts

Corona Functions:

Corona Function Definitions:

( ) indicates variable args and { } places them in a table where

they processed in standard way

Corona More function definitions:

Corona Calling functions:

foo(args)

simple call returning zero or more values.

t.f(args)

calling function store in field f of table t

local function f(mode, value)

Corona EventListeners:

Corona’s event listeners are part of the

Corona framework and not part of the Lua

programming language.

http://developer.anscamobile.com/content/events-and-listeners

Corona EventListeners:

and program scope to register for specific

events to respond to.

http://developer.anscamobile.com/content/events-and-listeners

Corona EventListeners:

There are two types of event listeners

‘Runtime’ dispatched by the system

‘Display-object’ self-explanatory.

http://developer.anscamobile.com/content/events-and-listeners

Corona Runtime Event Listeners:

local function onEnterFrame(event)

print (event.name)

end

Runtime:addEventListener(“enterFrame”,onEnterFrame)

http://developer.anscamobile.com/content/events-and-listeners

Corona Display Object Event Listeners:

local button = display.newImage(“button.png”,15,25);

local function button:touch(event)

print (event.name)

end

button:addEventListener(“touch”,button)

http://developer.anscamobile.com/content/events-and-listeners

local listener = function(event)

print( event.name, event.time )

end

Runtime:addEventListener("enterFrame", listener)

cicaza @ anscamobile dot com

Corona SDK

Code Less Play More.