addKeyListener for Frame doesn't work - no reaction to keys

Question

1.00/5 (1 vote)

See more:

Why don't I get printouts after typing arrowkeys? I get the image and the striped panel.
What other information would be needed to identify the problem?

Java

public class  MyFrame extends Frame {
	
	public MyFrame(String title) { 
		
		super(title);

		Container panel = new StripedPanel();
                add(panel, BorderLayout.CENTER);

/*
* GetImage is a class extending Component
*/
		Component image = new GetImage("1.gif"); 
	        panel.add(image);

	        pack();

	        EventQueue.invokeLater(new Runnable() {
			public void run() {
				setVisible(true);
			}
		});

	        addKeyListener(new KeyAdapter() {
			public void keyTyped(KeyEvent e) {
				int c=e.getKeyCode();
				if (c == KeyEvent.VK_UP) {
					System.out.println("Up");
//...

Posted 19-Apr-13 5:58am

themrpacu

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2 solutions

Solution 2

Hi there, if you are using java 7 i suggest using a KeyboardFocusManager. Use it something like this:

Java

public class yourClass{
      KeyBoardFocusManager manager;

      public void aMethod(){

          //doing something with your frame in this method
          //like add components, seting the layout, the size etc.


          manager=KeyboardFocusManager.getCurrentKeyboardFocusManager();
          manager.addKeyEventDispatcher(new MyKeyEventDispatcher());


      }

}

//create a private class for recognizing the keys you pressed.
      private class MyKeyEventDispatcher implements KeyEventDispatcher{

		@Override
		public boolean dispatchKeyEvent(KeyEvent e) {
			
			if(e.getID()==KeyEvent.KEY_PRESSED){
				if(e.getKeyCode()==KeyEvent.VK_UP){
					

                                         //do whatever you want to do on pressing up
				}
			}
			return false;
		}

Here the oracle link to find out more about KeyBoardFocusManager: http://docs.oracle.com/javase/1.5.0/docs/api/java/awt/KeyboardFocusManager.html[^]

Hope it helps.

Posted 22-Apr-13 4:58am

nameJulian

Updated 22-Apr-13 5:05am

v3

Comments

themrpacu 24-Apr-13 20:38pm

I appreciate the solution, but the problem had already been solved. Thanks anyway!

nameJulian 25-Apr-13 14:58pm

You're welcome.

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themrpacu · Accepted Answer · 2013-04-19T09:59:00

Solution 1

It's unbelievable nobody has noticed it. KeyTyped does not react to arrowkeys!

http://www.leepoint.net/notes-java/GUI-lowlevel/keyboard/keyboard.html[^]

Posted 19-Apr-13 9:59am

themrpacu