How move code from one class to other?

Question

I have a .fla file.
There i have some keyframes with labels.
On .fla file in property in Class field i adde MyMatching class.
Also i have main code:
package
     import flash.display.MovieClip;
     import flash.events.MouseEvent;
     import flash.text.TextField;
     public class MyMatching extends MovieClip
          var play_btn:MyButton = new MyButton();
          var kyky:MyTimer;
          public function MyMatching():void
               welcomeScreen();
          public function welcomeScreen():void
               stop();
               trace("working");
               play_btn.x = 210;
               play_btn.y = 300;
               addChild(play_btn);
               play_btn.addEventListener(MouseEvent.CLICK, goToLevel_1);
          public function goToLevel_1(event:MouseEvent)
               trace("level 1");
               play_btn.visible = false;
               gotoAndStop('Level1Screen');               
               if (kyky==undefined) {
                    kyky = new MyTimer();
And i have other class:
package
     import flash.display.MovieClip;
     import flash.display.Stage;
     import flash.utils.getTimer;
     import flash.text.TextField;
     public class MyTimer extends Stage
          import flash.utils.getTimer;
          var gameStartTime:uint;
          var gameTime:uint;
          var gameTimeField:TextField;
          function mainFunction():void
               gameTimeField = new TextField();
               addChild(gameTimeField);
               gameStartTime=getTimer();
               gameTime=0;
               addEventListener(Event.ENTER_FRAME,showTime);
          function showTime(event:Event)
               gameTime=getTimer()-gameStartTime;
               gameTimeField.text="You plaing: "+clockTime(gameTime);
          function clockTime(ms:int)
               var seconds:int=Math.floor(ms/1000);
               var minutes:int=Math.floor(seconds/60);
               seconds-=minutes*60;
               var timeString:String=minutes+":"+String(seconds+100).substr(1,2);
               return timeString;
Ho i can play code from class MyTimer in goToLevel_1 function(this function stand in my main class MyMatching) ?
Thank you.

Answer 1

First of all your MyTimer class is written wrong and sloppy.
Why does it extend Stage? The most compact class to extend under the circumstances is Sprite.
Also, it is very important to get into habit of datatype declarations. Not only it is good practice, in your case good compiler will throw error because although you return String, function doesn't return anything.
In addition, it is important to declare namespaces like private public and protected inside classes. Not function clickTime():String but private function clockTime():String or public function clickTime():String.
As for how to show your time elsewhere - you just need to create instnace of it and add it to disaply list:
var myTimer:MyTimer = new MyTimer();
addChild(myTimer);
With that said, your class should look like this:
package 
     import flash.display.Sprite;
     import flash.events.Event;
     import flash.display.MovieClip;
     import flash.utils.getTimer;
     import flash.text.TextField;
     public class MyTimer extends Sprite
          private var gameStartTime:uint;
          private var gameTime:uint;
          private var gameTimeField:TextField;
          public function MyTimer()
               gameTimeField = new TextField();
               addChild(gameTimeField);
               gameStartTime = getTimer();
               gameTime = 0;
               addEventListener(Event.ENTER_FRAME,showTime);
          private function showTime(event:Event):void
               gameTime = getTimer() - gameStartTime;
               gameTimeField.text = "You playing: " + clockTime(gameTime);
          private function clockTime(ms:int):String
               var seconds:int = Math.floor(ms / 1000);
               var minutes:int = Math.floor(seconds / 60);
               var timeString:String = minutes + ":" + String(seconds + 100).substr(1, 2);
               return timeString;