Sequentially-specific combination of keys held for function? - actionscript-3

Question

I'm trying to give my character in a platformer game a movement mechanic in which holding the left key then also the right will cause the character to still move left but at a slower pace (i.e. movementSpeed/2) as if moon-walking (and visa versa):
public var leftKey:Boolean = false;
public var rightKey:Boolean = false;
public var upKey:Boolean = false;
public var leftFlag:Boolean = false;
function ifKeyDown(event:KeyboardEvent):void
{
if (event.keyCode == Keyboard.LEFT && rightKey == false)
{
leftKey = true;
if (event.keyCode == Keyboard.LEFT && event.keyCode == Keyboard.RIGHT)
{
leftFlag = true;
trace("leftFlag true");
}
}
if (event.keyCode == Keyboard.RIGHT && leftKey == false)
{
rightKey = true;
}
}
function ifKeyUp(event:KeyboardEvent):void
{
if (event.keyCode == Keyboard.LEFT)
{
leftKey = false;
leftFlag = false;
}
if (event.keyCode == Keyboard.RIGHT)
{
rightKey = false;
}
}
public function ifEnterFrame(event:Event):void
{
if (leftKey == true && leftFlag == false)
{
player1_mc.x -= mainSpeed;
trace("L");
}
if (rightKey == true && leftFlag == false)
{
player1_mc.x += mainSpeed;
trace("R");
}
if (leftKey == true && rightKey == true)
{
if (leftFlag == true)
{
player1_mc.x -= mainSpeed/2;
trace("L + R");
}
else
{
player1_mc.x += mainSpeed/2;
trace("R + L");
}
}
My output would look like this:
I hold left key
L
L
L
L
I let go of left key. Then,
I hold right key
R
R
R
R
I let go of right key. Then,
I hold right then also hold left
L
R
R+L
L
R
R+L
I let go of both. Then,
I hold left then also right
L
R
R+L
L
R
R+L
Though I know by my traces that the leftFlag is not being run, I've spent hours trying to figure out why to no avail. :(

Answer 1

I think your problem is this expression:
event.keyCode == Keyboard.LEFT && event.keyCode == Keyboard.RIGHT
Though I am not familiar with actionscript, if it is anything like Java, the keyboard events are called once for each key press. "event" corresponds to only one key, not two different keys, and thus your expression will always return false.
The solution to your problem will probably involve something like this in both the key pressed and released functions.
if (event.keyCode == Keyboard.LEFT)
{
if (leftFlag)
{
//code here
}
if (rightFlag)
{
//code here
}
}
if (event.keyCode == Keyboard.RIGHT)
{
if (leftFlag)
{
//code here
}
if (rightFlag)
{
//code here
}
}
Hope that helps!