Hi,
I’m currently making a asteroids-like game and I encountered a problem with detecting key presses.
I’m using the key class made by senocular, which is:
package {
import flash.display.Stage;
import flash.events.Event;
import flash.events.KeyboardEvent;
import flash.ui.Keyboard;
/**
* 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):void {
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();
}
}
}
In my main code I access it by (one example):
if (Key.isDown(Keyboard.UP))
{
thrust = .5;
}
The problem (that I also had the same problem not using this class as well) is that when a user is pushing down the space bar and the up key, when they push the left key, it doesn’t trigger (but if I try space + up + left it does trigger). I researched a little bit on the web and I think it is something to do with operating systems (I use Win. XP).
Any help would be greatly appreciated! Thanks!
