-
Key events class...
Hi,
I've got a problem in a game i'm making with jumping. I'm trying to implement a double jump, and I think I need a way of checking if a key has been pressed, but that doesnt continue checking if the key is being held.
I found a nice class on the web to replace the class we lost with AS3, which is below. using it, i can do:
if(Key.isDown(Keyboard.UP)){ //code }
and it works really well. however for the jump, i need a method inside the key class that just returns true the moment the key is pressed, and then goes back to false.
I think that's what i need, anyway.. if anyone has any suggestions as to how to implement as double jump, i'd love to hear them too!
the code's below
thanks for any help!
Code:
// Key.as
package {
import flash.display.Stage;
import flash.events.Event;
import flash.events.KeyboardEvent;
/*
* The Key class recreates functionality of
* Key.isDown of ActionScript 1 and 2. Before using
* Key.isDown, you first need to initialize the
* Key class with a reference to the stage using
* its Key.initialize() method. For key
* codes use the flash.ui.Keyboard class.
*
* Usage:
* Key.initialize(stage);
* if (Key.isDown(Keyboard.LEFT)) {
* // Left key is being pressed
* }
*/
public class Key
{
private static var initialized:Boolean = false; // marks whether or not the class has been initialized
private static var keysDown:Object = new Object(); // stores key codes of all keys pressed
/*
* Initializes the key class creating assigning event
* handlers to capture necessary key events from the stage
*/
public static function initialize(stage:Stage)
{
if (!initialized)
{
// assign listeners for key presses and deactivation of the player
stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPressed);
stage.addEventListener(KeyboardEvent.KEY_UP, keyReleased);
stage.addEventListener(Event.DEACTIVATE, clearKeys);
// mark initialization as true so redundant
// calls do not reassign the event handlers
initialized = true;
}
}
/*
* Returns true or false if the key represented by the
* keyCode passed is being pressed
*/
public static function isDown(keyCode:uint):Boolean
{
if (!initialized)
{
// throw an error if isDown is used
// prior to Key class initialization
throw new Error("Key class has yet been initialized.");
}
return Boolean(keyCode in keysDown);
}
/**
* Event handler for capturing keys being pressed
*/
private static function keyPressed(event:KeyboardEvent):void
{
// create a property in keysDown with the name of the keyCode
keysDown[event.keyCode] = true;
}
/**
* Event handler for capturing keys being released
*/
private static function keyReleased(event:KeyboardEvent):void
{
if (event.keyCode in keysDown)
{
// delete the property in keysDown if it exists
delete keysDown[event.keyCode];
}
}
/**
* Event handler for Flash Player deactivation
*/
private static function clearKeys(event:Event):void
{
// clear all keys in keysDown since the player cannot
// detect keys being pressed or released when not focused
keysDown = new Object();
}
}
}
Posting Permissions
- You may not post new threads
- You may not post replies
- You may not post attachments
- You may not edit your posts
-
Forum Rules
|
Click Here to Expand Forum to Full Width
|