Trying to understand a function

Question

Im trying to understan a function that I found on the web. Iknow what the function does, It get the information about the webcam in your computer and post it on the textArea,

But the individual line are just a bit confused.

Any help ?

Thanks

private var camera:Camera;
private function list_change(evt:ListEvent):void {
var tList:List = evt.currentTarget as List;
var cameraName:String = tList.selectedIndex.toString();
camera = Camera.getCamera(cameraName);
textArea.text = ObjectUtil.toString(camera);
}

Answer 1

private var camera:Camera;

This line creates a variable of the class type Camera. It does not create an instance of the variable.

private function list_change(evt:ListEvent):void {

This line is a standard function heading. Because the argument is a ListEvent, it makes me think that this function is probably written as an event handler. Because of the name of the function, it is most like listening to the change event on a list.

var tList:List = evt.currentTarget as List;

This line creates a reference to the list that dispatched the event, which caused this handler to be executed.

var cameraName:String = tList.selectedIndex.toString();

This line converts the selectedIndex to a string. It's a bit odd to convert an index to a string, as opposed to some value. But the reason they do that looks to be on the next line..

camera = Camera.getCamera(cameraName);

This uses that camera variable (defined back in line 1) and actually gets an instance of the camera. It uses the "cameraName" which makes me think that the list that dispatched this change event contains a list of cameras available on the system.

textArea.text = ObjectUtil.toString(camera);

This converts the camera object to a string and displays it in a text area. Normally you wouldn't try to do this as it provides no valuable data. A default object will display strings as [Object object] or something similar. Perhaps the camera object has a custom string function; I don't have experience with that. Normally, you'd want to access properties of the object to get useful information, not try this on the object itself.

}

This line is the end of the function. The open bracket was in the 2nd line of code in the function definition.