How do I check if the user is pressing a key?

Question

In java I have a program that needs to check continuously if a user is pressing a key. So In psuedocode, somthing like

if (isPressing("w")) {  //do somthing } 

Thanks in advance!

Answer 1

In java you don't check if a key is pressed, instead you listen to KeyEvents. The right way to achieve your goal is to register a KeyEventDispatcher, and implement it to maintain the state of the desired key:

import java.awt.KeyEventDispatcher; import java.awt.KeyboardFocusManager; import java.awt.event.KeyEvent;  public class IsKeyPressed {     private static volatile boolean wPressed = false;     public static boolean isWPressed() {         synchronized (IsKeyPressed.class) {             return wPressed;         }     }      public static void main(String[] args) {         KeyboardFocusManager.getCurrentKeyboardFocusManager().addKeyEventDispatcher(new KeyEventDispatcher() {              @Override             public boolean dispatchKeyEvent(KeyEvent ke) {                 synchronized (IsKeyPressed.class) {                     switch (ke.getID()) {                     case KeyEvent.KEY_PRESSED:                         if (ke.getKeyCode() == KeyEvent.VK_W) {                             wPressed = true;                         }                         break;                      case KeyEvent.KEY_RELEASED:                         if (ke.getKeyCode() == KeyEvent.VK_W) {                             wPressed = false;                         }                         break;                     }                     return false;                 }             }         });     } } 

Then you can always use:

if (IsKeyPressed.isWPressed()) {     // do your thing. } 

You can, of course, use same method to implement isPressing("<some key>") with a map of keys and their state wrapped inside IsKeyPressed.