Actionscript 3制作角色跳转

Question

我正在制作一款平台游戏。但是我有问题，因为每当我按空格键跳跃时，角色都会陷入半空中。但是，我可以通过握住空格键来解决问题，角色将落地。

问题在mainJump()位于Boy类内。

我看到很多人通过使用动作时间线来解决问题，但我的主要问题是，无论如何，我可以通过使用外部类来解决问题吗？

主要类

package 
{ 
import flash.display.*; 
import flash.text.*; 
import flash.events.*; 
import flash.utils.Timer; 
import flash.text.*; 

public class experimentingMain extends MovieClip 
{ 
    var count:Number = 0; 
    var myTimer:Timer = new Timer(10,count); 

    var classBoy:Boy; 

    //var activateGravity:gravity = new gravity(); 

    var leftKey, rightKey, spaceKey, stopAnimation:Boolean; 

    public function experimentingMain() 
    { 
     myTimer.addEventListener(TimerEvent.TIMER, scoreUp); 
     myTimer.start(); 

     classBoy = new Boy(); 
     addChild(classBoy); 


     stage.addEventListener(KeyboardEvent.KEY_DOWN, pressTheDamnKey); 
     stage.addEventListener(KeyboardEvent.KEY_UP, liftTheDamnKey); 
    } 

    public function pressTheDamnKey(event:KeyboardEvent):void 
    { 
     if (event.keyCode == 37) 
     { 
      leftKey = true; 
      stopAnimation = false; 
     } 

     if (event.keyCode == 39) 
     { 
      rightKey = true; 
      stopAnimation = false; 
     } 

     if (event.keyCode == 32) 
     { 
      spaceKey = true; 
      stopAnimation = true; 
     } 
    } 

    public function liftTheDamnKey(event:KeyboardEvent):void 
    { 
     if (event.keyCode == 37) 
     { 
      leftKey = false; 
      stopAnimation = true; 
     } 

     if (event.keyCode == 39) 
     { 
      rightKey = false; 
      stopAnimation = true; 
     } 

     if (event.keyCode == 32) 
     { 
      spaceKey = false; 
      stopAnimation = true; 
     } 
    } 

    public function scoreUp(event:TimerEvent):void 
    { 
     scoreSystem.text = String("Score : "+myTimer.currentCount); 
    } 

} 
    } 

男孩类

package 
{ 
import flash.display.*; 
import flash.events.*; 

public class Boy extends MovieClip 
{ 
    var leftKeyDown:Boolean = false; 
    var upKeyDown:Boolean = false; 
    var rightKeyDown:Boolean = false; 
    var downKeyDown:Boolean = false; 
    //the main character's speed 
    var mainSpeed:Number = 5; 
    //whether or not the main guy is jumping 
    var mainJumping:Boolean = false; 
    //how quickly should the jump start off 
    var jumpSpeedLimit:int = 40; 
    //the current speed of the jump; 
    var jumpSpeed:Number = 0; 

    var theCharacter:MovieClip; 

    var currentX,currentY:int; 

    public function Boy() 
    { 
     this.x = 600; 
     this.y = 540; 

     addEventListener(Event.ENTER_FRAME, boyMove); 
    } 

    public function boyMove(event:Event):void 
    { 
     currentX = this.x; 
     currentY = this.y; 

     if (MovieClip(parent).leftKey) 
     { 
      currentX += mainSpeed; 
      MovieClip(this).scaleX = 1; 
     } 

     if (MovieClip(parent).rightKey) 
     { 
      currentX -= mainSpeed; 
      MovieClip(this).scaleX = -1; 
     } 

     if (MovieClip(parent).spaceKey) 
     { 
      mainJump(); 
     } 

     this.x = currentX; 
     this.y = currentY; 
    } 

    public function mainJump():void 
    { 
     currentY = this.y; 


     if (! mainJumping) 
     { 

      mainJumping = true; 
      jumpSpeed = jumpSpeedLimit * -1; 
      currentY += jumpSpeed; 
     } 
     else 
     { 
      if (jumpSpeed < 0) 
      { 
       jumpSpeed *= 1 - jumpSpeedLimit/250; 
       if (jumpSpeed > -jumpSpeedLimit/12) 
       { 
        jumpSpeed *= -2; 
       } 
      } 
     } 
     if (jumpSpeed > 0 && jumpSpeed <= jumpSpeedLimit) 
     { 
      jumpSpeed *= 1 + jumpSpeedLimit/120; 
     } 
     currentY += jumpSpeed; 

     if (currentY >= stage.stageHeight - MovieClip(this).height) 
     { 
      mainJumping = false; 
      currentY = stage.stageHeight - MovieClip(this).height; 
     } 
    } 
    } 
    } 

Answer 1

你已经有了一个mainJumping变量跳跃运行时，这只是事实。为什么不使用它？所有的

if (MovieClip(parent).spaceKey || mainJumping) 
{ 
    mainJump(); 
} 

Answer 2

首先，正式的代码，从而消除了时髦的东西，如“pressTheDamnKey”，这甚至不说明功能非常好，因为函数不能按一个键。这是一个事件处理程序，应该命名为keyDownHandler或onKeyDown，没有别的。其次，除了事件数据的直接问题之外，您很少想在事件处理程序中执行任何实际工作。而是呼吁实际工作的功能。处理程序处理事件，然后调用执行该工作的代码。这很好地分离出了关注点，当你想要其他其他也能够使小男孩除了enterFrameHandler之外还有动画，就像鼠标一样。

我可以想象，由于您的计时器每秒发射100次（每个10毫秒），因此您的跟踪日志会很快被“分数”线填满。我会改变这种情况，不要在计时器上触发，但要在得分实际发生变化时进行刷新。

除了意大利面代码之外，跳跃的问题在于，您是通过将按键的状态保存在变量中并让他不断检查它来确定是否按下了键。这有几个原因是不好的：1.他不应该需要向他的环境寻求信息，应该通过他拥有的任何物品或负责告诉他的物品给他。2.它需要你继续按住空格键，否则他将停止移动，因为他检查了是否被按住（见问题1）。

我会在下面解决所有这些问题，而不考虑得分，这完全是另一回事。

package 
{ 
    import flash.display.*; 
    import flash.events.*; 
    import flash.text.*; 
    import flash.utils.*; 

    // Sprite is preferred if you are not using the timeline 
    public class Application extends Sprite 
    { 
     private var boy:Boy; 

     public function Application() 
     { 
      boy = new Boy(); 
      addChild(boy); 
      boy.x = 600; // set these here, not in the boy 
      boy.y = 540; 
      stage.addEventListener(KeyboardEvent.KEY_DOWN, keyDownHandler); 
      stage.addEventListener(KeyboardEvent.KEY_UP, keyUpHandler ); 
     } 

     public function keyDownHandler(event:KeyboardEvent):void 
     { 
      switch(event.keyCode) 
      { 
       case 32: boy.jump(); 
         break; 
       case 37: boy.moveLeft(); 
         break; 
       case 39: boy.moveRight(); 
         break; 
       default: 
        // ignored 
        break; 
      } 
     } 

     public function keyUpHandler(event:KeyboardEvent):void 
     { 
      switch(event.keyCode) 
      { 
       // ignored for jumping (32) 
       case 37: // fall through 
       case 39: boy.stop(); 
         break; 
       default: 
        // ignored 
        break; 
      } 
     } 

    }//class 
}//package 

package 
{ 
    import flash.display.*; 
    import flash.events.*; 

    // It is assumed that there is an asset in the library 
    // that is typed to a Boy, thus it will be loaded onto 
    // the stage by the owner 
    public class Boy extends Sprite 
    { 
     private var horzSpeed :Number = 0; 
     private var vertSpeed :Number = 0; 
     private var floorHeight :Number; 
     private var jumpHeight :Number; 
     private var amJumping :Boolean = false; 

     public function Boy() 
     { 
      addEventListener(Event.ENTER_FRAME, enterFrameHandler); 
     } 

     public function moveLeft():void 
     { 
      horzSpeed = -1; 
     } 

     public function moveRight():void 
     { 
      horzSpeed = 1; 
     } 

     public function stop():void 
     { 
      horzSpeed = 0; 
     } 

     public function jump():void 
     { 
      if (amJumping) return; 
      floorHeight = y; 
      jumpHeight = floorHeight + 20; 
      vertSpeed = 2; 
      amJumping = true; 
      animateJump(); 
     } 

     private function enterFrameHandler(event:Event):void 
     { 
      animate(); 
     } 

     private function animate():void 
     { 
      x += horzSpeed; 
      if(amJumping) 
      { 
       animateJump(); 
      } 
     } 

     // Doing a simple version for this example. 
     // If you want an easier task of jumping with gravity, 
     // I recommend you employ Greensock's superb 
     // TweenLite tweening library. 
     private function animateJump():void 
     { 
      y += vertSpeed; 
      if(y >= jumpHeight) 
      { 
       y = jumpHeight; 
       vertSpeed = -2; 
      } 
      else if(y <= floorHeight) 
      { 
       y = floorHeight; 
       amJumping = false; 
      } 
     } 

    }//class 
}//package 

另一种方式接近这一点，可能是更好的途径长远，是让孩子甚至不负责移动自己。相反，你会在父母，他的主人或一些特殊的动画师课程中处理这个课程，这个课程负责按计划进行动画制作。在这个更加封闭的范例中，这个男孩只负责根据外部世界更新他自己的内部外表，告诉他他正在发生什么事情。他不再处理内部跳跃，而是负责做像他自己拥有的东西一样的动画，比如他的手臂和腿。