Cc3.2 + Lua (3) -- Lua class

[Nagging]

When using Lua, The cocos2d-x provides us withClass (classname, super)This function.

It allows us to easily define a class, or inherit a class from the cocos2d-x.

PS: Class () is the cocos2d-x for our encapsulated function, itself Lua does not have this function.

[Class]

Class FunctionsIs defined in "cocos2d-x-3.2/Cocos/scripting/LUA-bindings/script/extern. Lua.

-- Create an class. Function Class (classname, super) LocalSupertype =Type(Super) LocalCLS IfSupertype ~ = "Function"AndSupertype ~ = "Table"Then Supertype =Nil Super =Nil End IfSupertype = "function"Or(SuperAndSuper. _ ctype = 1)Then -- Inherited from native C ++ object CLS = {} IfSupertype = "table"Then -- Copy fields from super ForK, VIn Pairs(Super)DoCLS [k] = VEnd Cls. _ create = super. _ create Cls. Super = super Else Cls. _ create = super End Cls.Ctor=Function()End Cls. _ cname = classname Cls. _ ctype = 1 FunctionCls.New (...) LocalInstance = Cls. _ create (...) -- Copy fields from class to native object ForK, VIn pairs(CLS)DoInstance [k] = VEnd Instance. Class = CLS Instance:Ctor (...) ReturnInstance End Else -- Inherited from Lua object IfSuperThen CLS =Clone (Super) Cls. Super = super Else CLS = {ctor =Function()End} End Cls. _ cname = classname Cls. _ ctype = 2-- Lua Cls. _ Index = CLS FunctionCls.New (...) LocalInstance =Setretriable({}, CLs) Instance. Class = CLS Instance:Ctor (...) ReturnInstance End End ReturnCLS End

In Lua, the concept of a class is a table. The above function code mainly copies the table of the parent class super, and then defines two functions.Cls. New (...)AndCLS: ctor (...). It doesn't matter if we don't know the above Code, as long as we use it.

0. Usage

>Define a class:CLS =Class ("Class Name", "parent class ")

> Create an instance: OBJ = Cls. New ()

>Initialization function: CLS: ctor () is automatically called when an instance is created.

As long as you master these three steps, for our cocos2d-x development is enough!

1. Create a base class

First, createHeroClass, and then override the Hero class initialization function.Hero: ctor ().

Create another hero class instance objectHero. New ()Will automatically call the initialization function hero: ctor ().

Test output.

Note: The self in ctor () is the instance object, which is equivalent to this in the C ++ class.

650) This. width = 650; "src =" http://s3.51cto.com/wyfs02/M01/4C/DB/wKiom1RGn37wHdw6AAFXC7srOWg614.jpg "Title =" 1.png" alt = "wkiom1rgn37whdw6aafxc7srowg614.jpg"/>

2. inherit the parent class

In cocos2d-x development, it is often necessary to inherit the class in the engine, such as layer, Sprite.

Here is an example. Modify the above Hero class and inherit fromSprite.

650) This. width = 650; "src =" http://s3.51cto.com/wyfs02/M02/4C/DD/wKioL1RGoOWAXNLMAAIfl3ox2uQ600.jpg "Title =" 2.png" alt = "wkiol1rgoowaxnlmaaifl3ox2uq600.jpg"/>

3. For another example, inherit the layer class

I usually get usedCtor ()Only member variables of some classes are declared.

Then define a function.Create (), SetNew ()Encapsulate and then call it in create ()Init ()Function to initialize the instance object.

The advantage is that I use the same method in C ++.

 3.1 define a class inherited from Layer

650) This. width = 650; "src =" http://s3.51cto.com/wyfs02/M00/4C/DD/wKioL1RGpdHSkzvoAAS4LwqyVUM952.jpg "Title =" initpintu.png "alt =" wkiol1rgpdhskzvoaas4lwqyvum952.jpg "/>

 3.2 usage

> Create a scene scenario that contains the gamelayer layer: gamelayer: createscene ()

> Create a gamelayer layer -----------:Gamelayer: Create ()

> The Custom initialization function Init () is also called when gamelayer is created ()

> The member variables of the class are all in the ctor () .

 3.3 download code

Http://down.51cto.com/data/1886438

This article is from the "summer wind" blog, please be sure to keep this source http://shahdza.blog.51cto.com/2410787/1566513

Cc3.2 + Lua (3) -- Lua class