benwatts.ca » actionscript3 http://benwatts.ca Designer and Frontend Developer in Ottawa, Canada Fri, 22 Jul 2011 19:00:09 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 Creating Instances from the Library with Strings http://benwatts.ca/2009/creating-instances-from-the-library-with-strings/ http://benwatts.ca/2009/creating-instances-from-the-library-with-strings/#comments Sun, 20 Dec 2009 18:52:25 +0000 Ben http://www.benwatts.ca/?p=531 Problem: while working on an AS3 document you uncover an unusual situation in which you have a string class name that corresponds to something in the library. How does one do it?

I’ve come across this a number of times and found myself dropboxing this snippet so I would always have it with me …

import flash.utils.*;

/**
 * Takes a string classname, returns an instance of that class, if it exists.
 */
private function newInstanceFromString(className:String):*{
    try{
        var classRef:Class = getDefinitionByName(className) as Class;
        return new classRef();
    } catch( e:ReferenceError ){
        trace('Error: there was a problem creating an instance of the "'+className+'" class. Check your library and linkage to ensure it\'s there.');
        trace(e+"\n");
    }
}

See the AS3 livedocs for more information about getDefinitionByName, the super helpful method that makes it all work.

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