我为一个大学任务做了一个自上而下的射击游戏。当我按下鼠标左键射击子弹时，当他们与跟随播放器影片剪辑的敌人电影剪辑相撞时，他们会冻结，当发生这种情况时，仍然可以使用箭头键移动播放器影片剪辑，因此SWF没有坠毁。
敌人和子弹影片剪辑被放置在一个阵列中，两者都应该在彼此碰撞时被移除。
在输出窗口中，当子弹影片剪辑进入舞台时，我收到此错误消息
bullet hit baddie 0
TypeError：错误＃1034：类型强制失败：无法将flash.display :: Stage @ 2862e041转换为flash.display.MovieClip。
在Bullet / removeSelf（）
在Bullet / loop（）
在Main / loop（）
bullet hit baddie 0因为它在代码中被跟踪而存在。
Main.as
package
{
import flash.display.Stage;
import flash.display.MovieClip;
import flash.events.Event;
import flash.events.MouseEvent;
public class Main extends MovieClip
{
public var player:Player;
public var enemy:Enemy;
public var bulletList:Array = [];
public var mousePressed:Boolean = false; //keeps track of whether the mouse is currently pressed down
public var delayCounter:int = 0; //this adds delay between the shots
public var delayMax:int = 7; //change this number to shoot more or less rapidly
var enemies:Array = [];
public function Main():void
{
player = new Player(stage, 320, 240);
stage.addChild(player);
//stage.addEventListener(MouseEvent.CLICK, shootBullet, false, 0, true); //remove this
stage.addEventListener(MouseEvent.MOUSE_DOWN, mouseDownHandler, false, 0, true);
stage.addEventListener(MouseEvent.MOUSE_UP, mouseUpHandler, false, 0, true);
stage.addEventListener(Event.ENTER_FRAME, loop, false, 0, true);
for(var numBaddies=0; numBaddies<6;numBaddies++){
var enemy:Enemy = new Enemy(null);
enemy.x = numBaddies*50;
enemy.y = numBaddies*50
stage.addChild(enemy);
enemies.push(enemy);
}
}
public function loop(e:Event):void
{
if(mousePressed) // as long as the mouse is pressed...
{
delayCounter++; //increase the delayCounter by 1
if(delayCounter == delayMax) //if it reaches the max...
{
shootBullet(); //shoot a bullet
delayCounter = 0; //reset the delay counter so there is a pause between bullets
}
}
if(bulletList.length > 0)
{
for(var i:int = bulletList.length-1; i >= 0; i--)
{
bulletList[i].loop();
}
}
for(var h = 0; h<bulletList.length; ++h)
{
if(bulletList[h].hitTestObject(this)){
trace("player hit by baddie " + h);
}
}
for(var u:int=0; u<enemies.length; u++) {
Enemy(enemies[u]).moveTowards(player.x, player.y);
}
}
public function mouseDownHandler(e:MouseEvent):void //add this function
{
mousePressed = true; //set mousePressed to true
}
public function mouseUpHandler(e:MouseEvent):void //add this function
{
mousePressed = false; //reset this to false
}
public function shootBullet():void //delete the "e:MouseEvent" parameter
{
var bullet:Bullet = new Bullet(stage, player.x, player.y, player.rotation, enemies);
bullet.addEventListener(Event.REMOVED_FROM_STAGE, bulletRemoved, false, 0, true);
bulletList.push(bullet);
stage.addChild(bullet);
}
public function bulletRemoved(e:Event):void
{
e.currentTarget.removeEventListener(Event.REMOVED_FROM_STAGE, bulletRemoved);
bulletList.splice(bulletList.indexOf(e.currentTarget),1);
}
}
}
Enemy.as
package {
import flash.display.Stage;
import flash.display.MovieClip;
import flash.events.Event;
public class Enemy extends MovieClip {
public var bullets:Array;
public var stageRef:Stage;
private var enemyPositionX, enemyPositionY,xDistance,yDistance,myRotation:int;
public function Enemy(bulletList:Array) {
// constructor code
bullets = bulletList;
}
public function moveTowards(playerX:int, playerY:int){
xDistance = this.x - playerX;
yDistance = this.y - playerY;
myRotation = Math.atan2(yDistance, xDistance);
this.x -= 3 * Math.cos(myRotation);
this.y -= 3 * Math.sin(myRotation);
}
public function loopE():void{
for(var i=0; i<bullets.length; ++i)
{
if(bullets[i].hitTestObject(this)){
trace("you killed enemy " + i);
removeSelf();
}
}
}
private function removeSelf()
{
removeEventListener(Event.ENTER_FRAME, loopE);
if (stageRef.contains(this))
stageRef.removeChild(this);
}
}
}
Bullet.as
package
{
import flash.display.Stage;
import flash.display.MovieClip;
import flash.events.Event;
public class Bullet extends MovieClip
{
private var stageRef:Stage; //checks if the bullet leaves the screen borders
private var speed:Number = 10; //speed that the bullet will travel at
private var xVel:Number = 0; //current x velocity
private var yVel:Number = 0; //current y velocity
private var rotationInRadians = 0; //convenient to store our rotation in radians instead of degrees
private var allBaddies:Array;
//our constructor requires: the stage, the position of the bullet, and the direction the bullet should be facing
public function Bullet(stageRef:Stage, X:int, Y:int, rotationInDegrees:Number, enemies:Array):void
{
this.stageRef = stageRef;
this.x = X;
this.y = Y;
this.rotation = rotationInDegrees;
this.rotationInRadians = rotationInDegrees * Math.PI / 180; //convert degrees to radians, for trigonometry
allBaddies = enemies;
}
public function loop():void //we don't need to include the "e:Event" because we aren't using an EventListener
{
for(var b=0; b<allBaddies.length; ++b)
{
if(allBaddies[b].hitTestObject(this)){
trace("bullet hit baddie " + b);
removeSelf();
}
}
xVel = Math.cos(rotationInRadians) * speed; //uses the cosine to get the xVel from the speed and rotation
yVel = Math.sin(rotationInRadians) * speed; //uses the sine to get the yVel
x += xVel; //updates the position
y += yVel;
//if the bullet goes off the edge of the screen...
if(x > stageRef.stageWidth || x < 0 || y > stageRef.stageHeight || y < 0)
{
this.parent.removeChild(this); //remove the bullet
}
}
private function removeSelf()
{
removeEventListener(Event.ENTER_FRAME, loop);
if (MovieClip(root).stageRef.contains(this))
MovieClip(root).stageRef.removeChild(this);
}
}
}
所有的帮助表示赞赏，非常感谢先进。
答案 0 :(得分：0)
您收到了TypeError，因为root对MovieClip的转换失败了。当您在括号中包含前面带有类型名称的变量时，您声明该对象属于该类型（或扩展该类型）。在Bullet.removeSelf（）函数中，您有：MovieClip(root) - 但在这种情况下，root属于Stage类型，不会扩展MovieClip，从而导致错误。*
Stage类型确实同时包含contains和removeChild方法，因此您只需删除广告素材即可。实际上，Bullet类已经以stageRef的形式引用了阶段，因此您可以重用它。尝试将removeSelf()功能更改为：
private function removeSelf():void
{
removeEventListener(Event.ENTER_FRAME, loop);
if (stageRef.contains(this))
stageRef.removeChild(this);
}
*（更多信息：root属性的具体类型因具体情况而异。有时它实际上是MovieClip;有时候Bitmap;在您的情况下，如错误所示，它是Stage - 但唯一保证的类型是DisplayObject，这是最小的公分母类型，上面的类型都是从这个类型继承的。这是{{1上的Adobe文档property：http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/display/DisplayObject.html#root）