Question

这是用鼠标滚轮做到这一点的一种方法：

stage.addEventListener(MouseEvent.MOUSE_WHEEL, zoom);
function zoom(e:MouseEvent) {
    square.z+=20*e.delta;
}

你将如何使用KEY_UP和KEY_DOWN进行操作？

stage.addEventListener(KeyboardEvent.KEY_DOWN, zoom);
stage.addEventListener(KeyboardEvent.KEY_UP, zoom);
function zoom(e:MouseEvent):void{
}

Answer 1

啊，不，这个不会起作用

释放按下的键时会触发KEY_UP。它可以是任何关键。类似地，按下键时的KEY_DOWN

你真正需要做的事情：

//add event handler for key release
stage.addEventListener(KeyboardEvent.KEY_UP, keyUpHandler);
//Key release event handler
function keyUpHandler(e:KeyboardEvent):void {
    if(e.keyCode==Keyboard.UP) { //up key is pressed
        zoomIn();
    } else if(e.keyCode==Keyboard.DOWN) { //down key is pressed
        zoomOut();
    }
}

function zoomIn():void{
    square.z+=5;
}

function zoomOut():void{
    square.z-=5;
}

Answer 2

我认为这个会奏效：

stage.addEventListener(KeyboardEvent.KEY_DOWN, zoomIn);
stage.addEventListener(KeyboardEvent.KEY_UP, zoomOut);
function zoomIn(e:MouseEvent):void{
    square.z+=5;
}
function zoomOut(e:MouseEvent):void{
    square.z-=5;
}

如何使用KEY_UP放大符号并使用KEY_DOWN缩小？

2 个答案: