AS3: Single Key Press Only - actionscript-3

Question

I'm trying to create a platform game and I have the run, jump and double jump working. Now my problem is I want the player to press the jump button and the hero to jump only once instead of continuously jumping. If I hold the up button it will keep jumping which i do not want, i just want it to perform the jump once even if the key is still held down. I want the same for the double jump, how can i do this.
package
{
import flash.display.MovieClip;
import flash.events.Event;
import flash.events.KeyboardEvent;
import flash.ui.Keyboard;
public class Player extends MovieClip
{
//Player run speed setting
var RunSpeed:Number = 8;
//Player key presses
var RightKeyPress:Boolean = false;
var LeftKeyPress:Boolean = false;
var UpKeyPress:Boolean = false;
//Jump variables
var Gravity:Number = 1.5;
var JumpPower:Number = 0;
var CanJump:Boolean = false;
var DoubleJump:Boolean = false;
public function Player()
{
// constructor code
stage.addEventListener(KeyboardEvent.KEY_DOWN,KeyPressed);
addEventListener(Event.ENTER_FRAME,Update);
stage.addEventListener(KeyboardEvent.KEY_UP,KeyReleased);
}
function KeyPressed(event:KeyboardEvent)
{
//When Key is Down
if (event.keyCode == 39)
{
RightKeyPress = true;
}
if (event.keyCode == 37)
{
LeftKeyPress = true;
}
if (event.keyCode == 38)
{
UpKeyPress = true
}
}
function Update(event:Event)
{
//Adding gravity to the game world
JumpPower += Gravity;
//if player is more than 300 on the y-axis
if (this.y > 300)
{
//Player stays on the ground and can jump
JumpPower = 0;
CanJump = true;
DoubleJump = false;
}
//If player is on floor and right key is pressed then run right
if ((RightKeyPress && CanJump))
{
x += RunSpeed;
gotoAndStop('Run');
scaleX = 1;
}
else if ((LeftKeyPress && CanJump))
{
//Otherwise if on floor and left key is pressed run left
x -= RunSpeed;
gotoAndStop('Run');
scaleX = -1;
}
else if ((UpKeyPress && CanJump))
{
//Otherwise if on floor and up key is pressed then jump
JumpPower = -15;
CanJump = false;
gotoAndStop('Jump');
DoubleJump = true;
}
//If on floor and right and up key are pressed then jump
if ((RightKeyPress && UpKeyPress && CanJump))
{
JumpPower = -15;
CanJump = false;
gotoAndStop('Jump');
DoubleJump = true;
}
//If on floor and left and up key are pressed then jump
if ((LeftKeyPress && UpKeyPress && CanJump))
{
JumpPower = -15;
CanJump = false;
gotoAndStop('Jump');
DoubleJump = true;
}
//If jumped and right key is pressed then move right
if ((RightKeyPress && CanJump == false))
{
x += RunSpeed;
scaleX = 1;
}
else if ((LeftKeyPress && CanJump == false))
{
//Otherwise if jumped and left key is pressed then move left
x -= RunSpeed;
scaleX = -1;
}
//If in air and able to doublejump and pressed up key, then double jump
if (UpKeyPress && DoubleJump && JumpPower > -2)
{
JumpPower = -13;
DoubleJump = false;
gotoAndStop('DoubleJump');
}
//If on floor and no key is presses stay idle
if ((!RightKeyPress && !LeftKeyPress && CanJump))
{
gotoAndStop('Idle');
}
this.y += JumpPower;
}
function KeyReleased(event:KeyboardEvent)
{
if (event.keyCode == 39)
{
event.keyCode = 0;
RightKeyPress = false;
}
if (event.keyCode == 37)
{
event.keyCode = 0;
LeftKeyPress = false;
}
if (event.keyCode == 38)
{
event.keyCode = 0;
UpKeyPress = false;
}
}
}
}

Answer 1

I suspect that what is happening is that as soon as your player's y value meets the condition if (this.y > 300) you are enabling him to jump again, so as long as the key is held down he jumps because UpKeyPress && CanJump are both true.
My guess is that doing something like the following might get you closer yo your answer...
In your Update function:
function Update(event:Event)
{
//Adding gravity to the game world
JumpPower += Gravity;
//if player is more than 300 on the y-axis
if (this.y > 300)
{
//Player stays on the ground and can jump
JumpPower = 0;
// Do not allow another jump until the UpKey is pressed
//CanJump = true;
//DoubleJump = false;
}
...
Then in your KeyPressed function:
function KeyPressed(event:KeyboardEvent)
{
//When Key is Down
if (event.keyCode == 39)
{
RightKeyPress = true;
}
if (event.keyCode == 37)
{
LeftKeyPress = true;
}
if (event.keyCode == 38)
{
UpKeyPress = true
// Do not allow another jump until the UpKey is pressed
if (this.y > 300)
{
CanJump = true;
DoubleJump = false;
}
}
}
I also second shaunhusain's recommendation to set breakpoints and get comfortable with debugging code.