AS3保持mouseDown以提高速度/功率

Question

这就是我想要完成的事情;

随着对影片剪辑(cannon_mc)点击的射门被解雇(ball_mc)

较长的鼠标下降,球的射击速度应该增加.我的问题是;

实现这一目标的最有效方法是什么？用计时器或类似的东西;

    var isMouseDown:Boolean = false;
    var speed= 10;    

    myCannon.addEventListener(MouseEvent.MOUSE_DOWN,buttonPressed);

        function buttonPressed(event:MouseEvent){
            //trace("down");
            isMouseDown == true;

            if(isMouseDown == false)
            {
                speed == +1
            }

        }

Answer 1

MOUSE_DOWN事件仅触发一次.要获得您想要的效果,您需要MOUSE_DOWN和MOUSE_UP事件处理程序的组合.

您可以在MOUSE_DOWN事件中将变量设置为true以及当前时间戳 flash.utils.getTimer()

然后在MOUSE_UP上,如果您在MOUSE_DOWN中设置的变量为true,则计算经过的时间并相应地设置功率.

例:

var isMouseDown:Boolean = false;
var mouseDownBegin:int;
var speed = 10; 
var speed_inc = 2; // give it in per second
var speed_max = 100; // max speed possible

// add event handlers
myCannon.addEventListener(MouseEvent.MOUSE_DOWN, buttonPressed);
myCannon.addEventListener(MouseEvent.MOUSE_UP, buttonReleased);

function buttonPressed(event:MouseEvent){
    isMouseDown = true;
    mouseDownBegin = flash.utils.getTimer();
}

function buttonReleased(event:MouseEvent){
    if(isMouseDown == true){
        // get time between press and release
        var timeElapsed = flash.utils.getTimer() - mouseDownBegin;

        // reset isMouseDown
        isMouseDown = false;

        // compute speed
        speed += int(Math.floor(speed_inc * (timeElapsed / 1000.0)));
        speed = Math.min(speed, speed_max);

        // code to fire ball with new speed
        // .......
    }
}

您还可以添加ENTER_FRAME事件并为功率计或其他内容设置动画以获得视觉效果

更新
正如The_asMan指出的那样,MOUSE_UP如果在舞台外拖动并释放鼠标,则不会触发事件.为了处理这种情况MOUSE_LEAVE,使用回调作为事件的add和事件监听器作为buttonReleased函数的副本,但它接受一个Event对象:

function buttonReleasedOutsideStage(event:Event){
    if(isMouseDown == true){
        // get time between press and release
        var timeElapsed = flash.utils.getTimer() - mouseDownBegin;

        // reset isMouseDown
        isMouseDown = false;

        // compute speed
        speed += int(Math.floor(speed_inc * (timeElapsed / 1000.0)));
        speed = Math.min(speed, speed_max);

        // code to fire ball with new speed
        // .......
    }
}
stage.addEventListener(Event.MOUSE_LEAVE, buttonReleasedOutsideStage);