As3 collision test - actionscript-3

Question

Im doing a space invaders game in flash when i came to collisions i had a 1061 error possibly undefined hittestobject through a reference with a static type class....
How can i fix that? tried many ways can't get rid of that error
/* Código que pára a timeline na 1 frame para que o menu continue apresentado*/
stop();
/*Movimenta a nave fazendo a seguir os movimentos do rato e esconde o cursor do sistema operacional*/
stage.addChild(arma_tiro);
arma_tiro.mouseEnabled = false;
arma_tiro.addEventListener(Event.ENTER_FRAME, fl_CustomMouseCursor);
function fl_CustomMouseCursor(event:Event)
{
arma_tiro.x = stage.mouseX;
}
Mouse.hide();
/* Mouse Click Event
Clicking on the specified symbol instance executes a function in which you can add your own custom code.
Instructions:
1. Add your custom code on a new line after the line that says "// Start your custom code" below.
The code will execute when the symbol instance is clicked.
*/
stage.addEventListener(MouseEvent.CLICK, fl_MouseClickHandler_3);
function fl_MouseClickHandler_3(event:MouseEvent):void
{
var bullet:bullet_ = new bullet_();
addChild(bullet);
bullet.x=arma_tiro.x;
bullet.y=arma_tiro.y;
bullet.addEventListener(Event.ENTER_FRAME, moverbala);
}
function moverbala(event:Event):void // função para mover a bala para cima */
{
event.target.y=event.target.y-20;
}
//stage.addEventListener(Event.ENTER_FRAME, Primeira);
setInterval(Primeira, 1000) ; //define intervalo de tempo entre as varias repetiçoes da funçao
function Primeira(){ //funçao de spawn de nave 1
var invader1:invader_1 = new invader_1();
addChild(invader1);
invader1.x=0;
invader1.y=15;
invader1.addEventListener(Event.ENTER_FRAME, mover1);
}
function mover1(event:Event):void // função para mover a nave para lado direito */
{
event.target.x+=10;
}
//Nave 2
setInterval(Segunda, 1000) ; //define intervalo de tempo entre as varias repetiçoes da funçao
function Segunda(){ //funçao de spawn de nave 1
var invader2:invader_2 = new invader_2();
addChild(invader2);
invader2.x=0;
invader2.y=45;
invader2.addEventListener(Event.ENTER_FRAME, mover2);
}
function mover2(event:Event):void // função para mover a nave para lado direito */
{
event.target.x+=10;
}
//Nave 3
setInterval(Terceira, 1000) ; //define intervalo de tempo entre as varias repetiçoes da funçao
function Terceira(){ //funçao de spawn de nave 1
var invader3:invader_3 = new invader_3();
addChild(invader3);
invader3.x=0;
invader3.y=85;
invader3.addEventListener(Event.ENTER_FRAME, mover3);
}
function mover3(event:Event):void // função para mover a nave para lado direito */
{
event.target.x+=10;
}
// error line
if (bullet_.hitTestObject(invader_1))
{
//Remove bullet and enemy
mcGameStage.removeChild(bullet_);
mcGameStage.removeChild(invader_1);
}

Answer 1

it seems that bullet_ is a class and not an instance so you cannon call hitTestObject on it.
maybe try replace bullet_ by bullet.
there are many solution to do that but the simplest for me would be to keep 2 array, one for the bullets, one for the enemies.
so add arrays:
// create the array for the bullets
bullets :Array = [];
// create the array for the enemies
enemies :Array = [];
add an onEnterFrame event listener to do the tests and the game logic on each frame:
addEventListener( Event.ENTER_FRAME, _gameLoop );
change your function to create bullets and enemies:
function fl_MouseClickHandler_3( event:MouseEvent ):void
{
// create the bullet
var bullet:bullet_ = new bullet_();
addChild(bullet);
bullet.x=arma_tiro.x;
bullet.y=arma_tiro.y;
// add the bullet to the bullets array
bullets.push( bullet );
}
function Primeira():void
{
var invader1:invader_1 = new invader_1();
addChild(invader1);
invader1.x=0;
invader1.y=15;
enemies.push( invader1 );
}
function Segunda():void
{
var invader2:invader_2 = new invader_2();
addChild(invader2);
invader2.x=0;
invader2.y=45;
enemies.push( invader2 );
}
function Terceira():void
{
var invader3:invader_3 = new invader_3();
addChild(invader3);
invader3.x=0;
invader3.y=85;
enemies.push( invader3 );
}
now create the game loop function:
function _gameLoop():void
{
var firstLoop:Boolean = true;
// loop to move/remove the bullets
for( var a:int = bullets.length-1; a>=0; a-- )
{
bullets[a].y -= 20;
// if the bullet is not on screen anymore, remove it from array
if( bullets[j].y < 0 )
{
removeChild( bullet[a] );
bullets.splice(a,1);
continue;
}
}
// loop enemies
for( var i:int = enemies.length-1; i>=0; i-- )
{
// move the enemy
enemies[i].x += 10;
// loop the bullets to see if on collide the enemy
for( var j:int = bullets.length-1; j>=0; j-- )
{
// test collision with the enemy
if( enemies[i].hitTestObject( bullets[j] )
{
// make your enemy dead
removeChild( enemies[i] );
// remove it from the array
enemies.splice(i,1);
}
}
}
}
Hope this could helps you