闪存空间密钥识别失败

Question

I've been working on my platform game and I decided to create an air attack for the character. Everything's working fine except for the fact that Flash fails to recognize that space has been pressed after holding down the up and left keys ( UP + LEFT -> SPACE ). However, this works fine: ( UP + RIGHT -> SPACE ). At first I thought the problem was simply a fault in my code. However, after carefully searching through my code carefully I came to the conclusion that the problem wasn't in the code but rather Flash itself.

Next I created a separate Flash file to test this to make sure that the fault was not in the code. I created a space bar Movie Clip and a Movie Clip for each of the arrow keys ( with instance names "space", "right", "left" etc ). Then I added this code to listen for key presses and releases:

var space_pressed:Boolean = false;
var up_pressed:Boolean = false;
var down_pressed:Boolean = false;
var left_pressed:Boolean = false;
var right_pressed:Boolean = false;



stage.addEventListener(KeyboardEvent.KEY_DOWN,key_down);
function key_down(e:KeyboardEvent){
    switch(e.keyCode){
        case (38):
        up_pressed=true;
        break;
        case (40):
        down_pressed=true;
        break;
        case (37):
        left_pressed=true;
        break;
        case (39):
        right_pressed=true;
        break;
        case (32):
        space_pressed=true;
        break;
    }   
}
stage.addEventListener(KeyboardEvent.KEY_UP,key_up);
function key_up(e:KeyboardEvent){
    switch(e.keyCode){
        case (38):
        up_pressed=false;
        break;
        case(40):
        down_pressed=false;
        break;
        case(37):
        left_pressed=false;
        break;
        case(39):
        right_pressed=false;
        break;
        case (32):
        space_pressed=false;
        break;
    }   
}

stage.addEventListener(Event.ENTER_FRAME,update_visual);
function update_visual(e:Event){
    if(space_pressed){
        space.alpha=1;
    }else{
        space.alpha=.5;
    }

    if(up_pressed){
        up.alpha=1;
    }else{
        up.alpha=.5;
    }

    if(down_pressed){
        down.alpha=1;
    }else{
        down.alpha=.5;
    }

    if(left_pressed){
        left.alpha=1;
    }else{
        left.alpha=.5;
    }

    if(right_pressed){
        right.alpha=1;
    }else{
        right.alpha=.5;
    }
}

When a key is pressed the key representing it will have an alpha of 1, otherwise it will have an alpha of 0.5. And, just as I thought, after holding down the up and left keys, space would not show up. But space press is recognized after holding down the up and right keys.

My next logical assumption was that this was simply a result of the order of the cases for my press and release key switch blocks. However, after rearranging the order of these cases, I still had the same result. This is a serious problem for any Flash game developer working with key presses and releases. If anyone knows why this is happening or has any advise on getting around this issue, please help me out! Thanks in advance.

UPDATE: I also just discovered the opposite is also true. ( DOWN + RIGHT -> SPACE ) doesn't work while ( DOWN + LEFT -> SPACE ) works fine.

Answer 1

Good news, I finally figured out the problem. It wasn't because of my code or Flash, it was because of "Keyboard Ghosting" http://www.microsoft.com/appliedsciences/antighostingexplained.mspx . I'm going to leave this question on the forum in case anyone else is struggling with the same problem.