Having an issue with Flash Actionscript3 - actionscript-3

Question

Wondering if you guys can help me. I've used online tutorials to create the following.
I am working on a small flash project and I've hit a wall. Basically, I've got 3 scenes. A home page, and 2 games. My home page and one of the games are programmed on the timeline within an actions layer. The third game is applied to a Main.as. The problem is that I want to apply a button called home to the Flappy game, but since I've used the .as file for this code, I'm unsure how to do it.
Basically, my question is "How do I add a button to the "Flappy" Scene? Each time i try to do it and run a test, It's playing the Flappy Game over the Scene 1.
Main.as ("Flappy" Scene3)
package{
import flash.display.MovieClip;
import flash.events.KeyboardEvent;
import flash.ui.Keyboard;
import flash.events.Event; //used for ENTER_FRAME event
//import flash.events.MouseEvent;
public class Main extends MovieClip{
//These are all of the constants used.
const gravity:Number = 1.5; //gravity of the game. How fast ball falls
const dist_btw_obstacles:Number = 300; //distance between two obstacles
const ob_speed:Number = 8; //speed of the obstacle
const jump_force:Number = 15; //force with which it jumps
//variables
var player:Player = new Player();
var lastob:Obstacle = new Obstacle(); //varible to store the last obstacle in the obstacle array
var obstacles:Array = new Array(); //an array to store all the obstacles
var yspeed:Number = 0; //A variable representing the vertical speed of the bird
var score:Number = 0; //A variable representing the score
public function Main(){
init();
}
function init():void {
//initialize all the variables
player = new Player();
lastob = new Obstacle();
obstacles = new Array();
yspeed = 0;
score = 0;
//add player to center of the stage the stage
player.x = stage.stageWidth/2;
player.y = stage.stageHeight/2;
addChild(player);
//create 3 obstacles ()
createObstacle();
createObstacle();
createObstacle();
//Add EnterFrame EventListeners (which is called every frame) and KeyBoard EventListeners
addEventListener(Event.ENTER_FRAME,onEnterFrameHandler);
stage.addEventListener(KeyboardEvent.KEY_UP, key_up);
}
private function key_up(event:KeyboardEvent){
if(event.keyCode == Keyboard.SPACE){
//If space is pressed then make the bird
yspeed = -jump_force;
}
}
function restart(){
if(contains(player))
removeChild(player);
for(var i:int = 0; i < obstacles.length; ++i){
if(contains(obstacles[i]) && obstacles[i] != null)
removeChild(obstacles[i]);
obstacles[i] = null;
}
obstacles.slice(0);
init();
}
function onEnterFrameHandler(event:Event){
//update player
yspeed += gravity;
player.y += yspeed;
//restart if the player touches the ground
if(player.y + player.height/2 > stage.stageHeight){
restart();
}
//Don't allow the sheep to go above the screen
if(player.y - player.height/2 < 0){
player.y = player.height/2;
}
//update obstacles
for(var i:int = 0;i<obstacles.length;++i){
updateObstacle(i);
}
//display the score
scoretxt.text = String(score);
}
//This functions update the obstacle
function updateObstacle(i:int){
var ob:Obstacle = obstacles[i];
if(ob == null)
return;
ob.x -= ob_speed;
if(ob.x < -ob.width){
//if an obstacle reaches left of the stage then change its position to the back of the last obstacle
changeObstacle(ob);
}
//If the bird hits an obstacle then restart the game
if(ob.hitTestPoint(player.x + player.width/2,player.y + player.height/2,true)
|| ob.hitTestPoint(player.x + player.width/2,player.y - player.height/2,true)
|| ob.hitTestPoint(player.x - player.width/2,player.y + player.height/2,true)
|| ob.hitTestPoint(player.x - player.width/2,player.y - player.height/2,true)){
restart();
}
//If the bird got through the obstacle without hitting it then increase the score
if((player.x - player.width/2 > ob.x + ob.width/2) && !ob.covered){
++score;
ob.covered = true;
}
}
//This function changes the position of the obstacle such that it will be the last obstacle and it also randomizes its y position
function changeObstacle(ob:Obstacle){
ob.x = lastob.x + dist_btw_obstacles;
ob.y = 100+Math.random()*(stage.stageHeight-200);
lastob = ob;
ob.covered = false;
}
//this function creates an obstacle
function createObstacle(){
var ob:Obstacle = new Obstacle();
if(lastob.x == 0)
ob.x = 800;
else
ob.x = lastob.x + dist_btw_obstacles;
ob.y = 100+Math.random()*(stage.stageHeight-200);
addChild(ob);
obstacles.push(ob);
lastob = ob;
}
}
}
Here is the code for my main page called "Scenery" (Scene 1) which is in an actions layer of timeline.
stop();
import flash.events.MouseEvent;
sun1.addEventListener(MouseEvent.CLICK,cloudy);
function cloudy (e:MouseEvent){
cloud1.x = cloud1.x + 10;
cloud2.x = cloud2.x - 10;
}
pong_btn.addEventListener(MouseEvent.MOUSE_DOWN, mouseDownHandler);
function mouseDownHandler(event:MouseEvent):void {
gotoAndStop(1, "SheepyPong");
}
dodge_btn.addEventListener(MouseEvent.MOUSE_DOWN, mouseDownHandler3);
function mouseDownHandler3(event:MouseEvent):void {
gotoAndStop(1, "Flappy");
}
This is my code for a very simple "SheepyPong" (Scene2) game which is linked to from front page:
var upPressed:Boolean = false;
var downPressed:Boolean = false;
var velocityX:Number = 5;
var velocityY:Number = 5;
movieClip_1.addEventListener(Event.ENTER_FRAME, fl_MoveInDirectionOfKey);
stage.addEventListener(KeyboardEvent.KEY_DOWN, fl_SetKeyPressed);
stage.addEventListener(KeyboardEvent.KEY_UP, fl_UnsetKeyPressed);
function fl_MoveInDirectionOfKey(event:Event)
{
if (upPressed)
{
movieClip_1.y -= 5;
}
if (downPressed)
{
movieClip_1.y += 5;
}
sheep.x += velocityX;
sheep.y += velocityY;
if(sheep.y + sheep.height/2 > stage.stageHeight || sheep.y - sheep.height/2 < 0){
velocityY *= -1
}
if(sheep.hitTestObject(AI) || sheep.hitTestObject(movieClip_1)){
velocityX *= -1;
}
if (sheep.x < 0) {
score2.text = (int(score2.text) +1).toString();
sheep.x = 275;
sheep.y = 200;
velocityX *= -1;
}
if (sheep.x > stage.stageWidth) {
score1.text = (int(score1.text) +1).toString();
sheep.x = 275;
sheep.y = 200;
velocityX *= -1;
}
AI.y = sheep.y;
}
function fl_SetKeyPressed(event:KeyboardEvent):void
{
switch (event.keyCode)
{
case Keyboard.UP:
{
upPressed = true;
break;
}
case Keyboard.DOWN:
{
downPressed = true;
break;
}
}
}
function fl_UnsetKeyPressed(event:KeyboardEvent):void
{
switch (event.keyCode)
{
case Keyboard.UP:
{
upPressed = false;
break;
}
case Keyboard.DOWN:
{
downPressed = false;
break;
}
}//end of switch
}//end of function
home_btn.addEventListener(MouseEvent.MOUSE_DOWN, mouseDownHandler1);
function mouseDownHandler1(event:MouseEvent):void {
gotoAndStop(1, "Scenery");
}
I'm also getting this error in output when I run it. It's not actually affecting the outpu
TypeError: Error #1009: Cannot access a property or method of a null object reference.
at Main/onEnterFrameHandler()[/Users/mynamehere/Documents/Game/Main.as:91]
//This is line 91 in the Main.as file:
scoretxt.text = String(score);