as3变量名称和实例名称之间有什么区别？

Question

I stumbled across that while using the "this" keyword inside of my classes:

i have one MovieClip class that is added to the stage. from inside its instance seems to know the name i assigned to it in the properties (chapter1).

then it (chapter1) creates an instance of another class (Transition) into a variable (transition1):

var transition1:Transition = new Transition();

then i call an interior method of transition1 like this:

transition1.moveFromTo(this);

which is is tracing its name like this:

trace(this.name);

while tracing the name of chapter1 i get "chapter1" as its name. but inside of transition1 i get "instance1" through the very same way. i already figured out that i can assign the name via "transition1.name = transition1". That shows me that the variable name and the instance name i get through the .name property differ.

but I dont understand why I then have to create a variable to reference the instance.

Answer 1

The instance name is a way of referring to the movieclip.
The variable is the way to access functions, variables applicable to that movieclip.

var currentTile:MovieClip = this.getChildByName("MyClip") as MovieClip;
currentTile.someFunction();

From here you can manipulate the movieclip. If you created a variable, private to the chapter1 class, you would not have to name the movieclip as the scope of the variable would cover all the code in the class.

When you add a movieclip to the stage at design time, it seems to me flash assigns a variable called 'instancex' and names it 'instancex'. When you name it, it changes the names.
There is also no need to name the movieclip if the variable is within the scope of your code or if you dont have to refer to it at a later stage.
Another way of looking at it. The 'variable' is an object containing properties, functions. The 'instance name' is a property of the object.
I hope it helps.

Answer 2

name is a property of DisplayObject .

When you fill out the 'instance name' field in MovieClip properties via the Flash IDE, what actually happens is you give that MovieClip a value for name . Additionally, there is a variable created for you to use with the same name. It's essentially a shortcut so that you don't have to do something like this for all your MovieClips on the stage:

var myclip:MovieClip = getChildByName("myclip");

If you do no assign a name to a DisplayObject, it is automatically given a name, which will be something like instance3 . Try this code for example:

var mc:MovieClip = new MovieClip();
trace(mc.name); // instance1

In these cases, there is no variable created for you to use, and you'll have to create a reference to it yourself.