所以我正在开发一个使用多个 .as 文件的游戏 - 我正在尝试对游戏进行编程，但是当它到达 theGame.as 中的第 21 行时，它会不断出现以下错误 - 错误是......
TypeError: Error #2007: Parameter child must be non-null.
at flash.display::DisplayObjectContainer/addChild()
at theGame()[M:\Users\----\Documents\Programming For Fun\Flash\Tutorial - Menu System\theGame.as:21]
at main/changeState()[M:\Users\----\Documents\Programming For Fun\Flash\Tutorial - Menu System\main.as:23]
at mainMenu/brnP_Button()[M:\Users\----\Documents\Programming For Fun\Flash\Tutorial - Menu System\mainMenu.as:40]
Cannot display source code at this location.
我正在使用以下 .as 文件。
主文件
//main.as
package
{
import flash.display.*;
import flash.system.fscommand;
public class main extends MovieClip
{
public function main()
{
changeState(null, "menu");
}
public function changeState (currentState, nextState)
{
if (currentState != null)
{
removeChild(currentState);
}
switch(nextState)
{
case "menu": var mm:mainMenu = new mainMenu(changeState);
addChild(mm);
break;
case "game": var g:theGame = new theGame(changeState);
addChild(g);
break;
case "exit": fscommand("quit");
break;
}
}
}
}
主菜单.as `
//mainMenu.as
package
{
import flash.display.*;
import flash.events.*;
public class mainMenu extends MovieClip
{
var theCallBackFunction:Function;
private var ballX:Number = 10; // Declaring a variable known as ballX
private var ballY:Number = 0; // Declaring a variable knwon as ballY
private const GRAVITY:Number = 2; // Declaring a const variable known as gravity
public const ROTATION:Number = 1;
public const BOUNCE:Number = 0.9;
var gameBall:Ball = new Ball();
public function mainMenu(callBack)
{
addEventListener(Event.ENTER_FRAME, menuFrameHandler);
addChild(gameBall);
var btnPlay:mmPlay = new mmPlay();
btnPlay.addEventListener(MouseEvent.MOUSE_DOWN, brnP_Button);
btnPlay.x = width/2;
btnPlay.y = height/2 - btnPlay.height/2;
addChild(btnPlay);
var btnExit:mmExit = new mmExit();
btnExit.addEventListener(MouseEvent.MOUSE_DOWN, brnE_Button);
btnExit.x = width/2;
btnExit.y = height/2 - btnExit.height/2;
btnExit.y += btnExit.height + 4;
addChild(btnExit);
theCallBackFunction = callBack;
}
public function brnP_Button(e:MouseEvent)
{
removeEventListener(Event.ENTER_FRAME, menuFrameHandler);
theCallBackFunction(this, "game");
return;
}
public function brnE_Button(e:MouseEvent)
{
theCallBackFunction(this, "exit");
return;
}
private function menuFrameHandler (e:Event):void
{
// Gravitate the Ball
ballY += GRAVITY; // The ball is effected by gravity each frame
// Move The Ball
gameBall.x += ballX;
gameBall.y += ballY;
gameBall.rotation += ROTATION * ballX;
checkBoundaryCollision();
}
private function checkBoundaryCollision():void
{
var left:Number;
var right:Number;
var bottom:Number;
left = gameBall.x - (gameBall.width / 2);
right = gameBall.x + (gameBall.width / 2);
bottom = gameBall.y;
if (left < 0 && ballX < 0)
{
gameBall.x = (gameBall.width / 2)
ballX *= -1;
}
else if (right > stage.stageWidth && ballX > 0)
{
gameBall.x = stage.stageWidth - (gameBall.width / 2)
ballX *= -1;
}
else if (bottom > stage.stageHeight && ballY > 0)
{
gameBall.y = stage.stageHeight - (gameBall.height/2)
ballY *= -BOUNCE;
}
}
}
}
游戏.as
//theGame.as
package
{
import flash.display.MovieClip
import flash.text.TextField
import flash.events.Event
import flash.events.MouseEvent
public class theGame extends MovieClip
{
public const GRAVITY:Number = 2; // Declaring a const variable known as gravity
public const BOUNCE:Number = 0.8;
public const HIT:Number = 15;
public const ROTATION:Number = 1;
public var gameBall:Ball;
private var ballX:Number; // Declaring a variable known as ballX
private var ballY:Number; // Declaring a variable knwon as ballY
public function theGame(callBack): void
{
addChild(gameBall);
ballX = Math.random(); // Initalising ballX
ballY = Math.random(); // Initalising ballY
gameBall.buttonMode = true;
addEventListener(Event.ENTER_FRAME, gameFrameHandler);
addEventListener(MouseEvent.MOUSE_DOWN, mouseDownHandler);
}
private function gameFrameHandler (e:Event):void
{
// Gravitate the Ball
ballY += GRAVITY; // The ball is effected by gravity each frame
// Move The Ball
gameBall.x += ballX;
gameBall.y += ballY;
gameBall.rotation += ROTATION * ballX;
// Check Stage Boundaries For Collisions
checkBoundaryCollision();
}
private function mouseDownHandler (e:MouseEvent):void
{
// Hit the ball if it has been clicked
if (e.target == gameBall)
{
hit(e.target.mouseX, e.target.mouseY);
}
}
private function checkBoundaryCollision():void
{
var left:Number;
var right:Number;
var bottom:Number;
var top:Number;
left = gameBall.x - (gameBall.width / 2);
right = gameBall.x + (gameBall.width / 2);
bottom = gameBall.y + (gameBall.height / 2);
top = gameBall.y - (gameBall.height / 2);
if (left < 0 && ballX < 0)
{
gameBall.x = (gameBall.width / 2)
ballX *= -1;
}
else if (right > stage.stageWidth && ballX > 0)
{
gameBall.x = stage.stageWidth - (gameBall.width / 2)
ballX *= -1;
}
if (top < 42.70 && ballY < 0)
{
gameBall.y = 42.70 + (gameBall.height / 2)
ballY *= -1;
}
else if (bottom > stage.stageHeight && ballY >= 0)
{
gameBall.y = stage.stageHeight - (gameBall.height/2)
ballY *= -BOUNCE;
ballX *= BOUNCE;
}
}
private function hit(hitX:Number, hitY:Number):void
{
// Adjust vertical velocity
if (ballY > 0)
{
ballY *= -BOUNCE / 2;
}
ballY -= HIT;
//adjust horizontal veloity
if (ballX * hitX > 0)
{
ballX *= -BOUNCE;
}
ballX -= (hitX / gameBall.width * HIT);
}
}
}
我将如何解决这个问题？