I am trying to sense multiple keys at a time and I am wondering how to use a hash map to do this.

What do you mean? A hashmap maps key,value pairs - is that the sense of "key" you mean, or are you talking about "key" as in "keyboard" or do you mean "key" as in crypto, or what do you mean?

You don't use hash maps to sense keyboard keys, you use keyboard listeners for that.

Are you talking about handling a multiple key press scenario after it's detected? Like, user presses 'a', 'd', and 'e' at the same time?
I can imagine one way to do that using a hash map, but forget about the hash map for the moment. What is it you're trying to do? Figure out the requirements, then worry about how you'll implement it.

I am trying to sense 2 keys, CTRL and SPACE, but keylistener to my knowledge can only sense one key at a time unless both keys are pressed at the same time, in my cast they most likely wont be.

Edited 5 Years Ago by sirlink99: n/a

You'll probably need to use keypressed and keyreleased.

When keypressed fires, if the firing key is "CTRL" set a flag, controlDown, to true
When keyreleased fires, if the firing key is "CTRL", set that flag to false

If keypressed fires, and the firing key is "SPACE", check that flag to see what you need to do.

I'm sure there are other ways to handle this, some of which might be better. Probably reading through the tutorial that was posted would be a good idea.

here is my code. It doesn't seem to work and I don't know why.

import java.awt.event.*;
import java.awt.*;

import javax.swing.*;


public class CubeTimer extends JFrame implements ActionListener, KeyListener{

	double versionNum = 1.0; JFrame helpFrame;
	JFrame frame;
	JButton ok;
	Timer timer = new Timer (1,this); 
	int time = 0;
	double dispTime;
	int going = 0;
	JLabel display;
	boolean ctrl = false;
	boolean space = false;
	boolean wasCtrl = false;
	boolean wasSpace = false;
	
	public CubeTimer (){
		frame = new JFrame ("WP CubeTimer");
		frame.setSize (400,300);
		JPanel pane = new JPanel ();
		JMenuBar menubar = new JMenuBar();
		JMenu file = new JMenu ("File");
		JMenu help = new JMenu ("Help");
		JMenuItem close = new JMenuItem ("Close"); close.addActionListener(this); close.setActionCommand ("Close");
		JMenuItem helpOption = new JMenuItem ("Help"); helpOption.addActionListener(this); helpOption.setActionCommand("help");
		JMenuItem about = new JMenuItem ("About");about.addActionListener (this); about.setActionCommand ("About");
		file.add(close);
		help.add(helpOption);
		help.add(about);
		menubar.add(file);
		menubar.add(help);
		frame.setJMenuBar(menubar);
		display = new JLabel ("Press control and space to start/stop the timer.");
		pane.add (display);
		
		frame.add(pane);
		frame.setVisible(true);
	}
	
	public static void main (String[] args){
		CubeTimer ct = new CubeTimer ();
		
	}

	@Override
	public void keyPressed(KeyEvent e) {
		int key = e.getKeyCode();
		if (key == KeyEvent.VK_SPACE){
			space = true;
				if (ctrl = true && going == 0){
					timer.start();
					going = 1;
				}
				if (ctrl = true && going == 1 && wasCtrl != false && wasSpace != false){
					timer.stop();
				}
		}
		if (key == KeyEvent.VK_CONTROL){
			ctrl = true;
			if (space = true && going == 0 && wasCtrl != false && wasSpace != false){
				timer.start();
				going = 1;
			}
			else if (space = true && going == 1){
				timer.stop();
			}
		}
		
	}

	@Override
	public void keyReleased(KeyEvent e) {
		// TODO Auto-generated method stub
		int key = e.getKeyCode();
		if (key == KeyEvent.VK_SPACE){
			space = false;
			wasSpace = true;
		}
		if (key == KeyEvent.VK_CONTROL){
			ctrl = false;
			wasCtrl = true;
		}
	}

	@Override
	public void keyTyped(KeyEvent e) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void actionPerformed(ActionEvent e) {
		// TODO Auto-generated method stub
		if ("About".equals(e.getActionCommand ())){
			JFrame aboutFrame = new JFrame ("About");
			aboutFrame.setSize (400,300);
			aboutFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
			JPanel aboutPane = new JPanel ();
			aboutPane.setLayout (new GridLayout (4,1));
			ImageIcon logoImg = new ImageIcon ("LogoBlank.png");
			JLabel logoLabel = new JLabel (logoImg);
			aboutPane.add(logoLabel);
			JLabel version = new JLabel ("Version: " + versionNum, JLabel.CENTER);
			aboutPane.add (version);
			JLabel madeBy = new JLabel ("Made By: Warrior Productions (Adam Balint)", JLabel.CENTER);
			aboutPane.add(madeBy);
			JLabel email = new JLabel ("<html>Contact: <a href=\"WarriorProd@hotmail.com\"> WarriorProd@hotmail.com </a> </html> ", JLabel.CENTER);
			aboutPane.add (email);
			aboutFrame.add(aboutPane);
			aboutFrame.setVisible(true);
		}
		else if ("Close".equals(e.getActionCommand ())){
			frame.dispose();
		}
		else if ("help".equals(e.getActionCommand())){
			helpFrame = new JFrame ("Help");
			helpFrame.setSize (550,150);
			helpFrame.setDefaultCloseOperation (JFrame.DISPOSE_ON_CLOSE);
			JPanel pane = new JPanel ();
			JLabel instruct = new JLabel ("<html> <center>To start the timer: hold down left control and space. When released then the timer starts. <br>" + "<br>" + "To Stop the timer: Press both the left control and spacebar to stop the timer. </center></html>");
			ok = new JButton ("OK"); ok.addActionListener (this);ok.setActionCommand ("helpOK");
			pane.add (instruct);
			pane.add (ok);
			helpFrame.add(pane);
			helpFrame.setVisible(true);	
		}
		
		else if ("helpOK".equals (e.getActionCommand())){
			helpFrame.dispose();
		}
		else {
			time += 1;
			dispTime = time/100;
			display.setText ("" +dispTime);
		}
		
		
	}
	
}

You have been on DaniWeb long enough to know that "It doesn't seem to work" isn't good enough.
If you want someone to help, please give a proper description of your problem and the things you have already done to try to solve it.

I am pretty sure that sensing the keys isn't working. I changed it so the timer starts on space. It didn't start. So it is something with the keys.

Have you put print statements into your code to confirm whether the right things are being called? Don't try to guess that kind of thing - test whether it's right.

Did you remember to add the KeyListener to the relevant components??

That works somewhat. Here is my new code. I fixed the keysListener and added print statements, but now it starts when I press space not when I press both space and ctrl at the same time.

import java.awt.event.*;
import java.awt.*;

import javax.swing.*;


public class CubeTimer extends JFrame implements ActionListener, KeyListener{

	double versionNum = 1.0; JFrame helpFrame;
	JFrame frame;
	JButton ok;
	Timer timer = new Timer (1,this); 
	int time = 0;
	double dispTime;
	int going = 0;
	JLabel display;
	boolean ctrl = false;
	boolean space = false;
	boolean wasCtrl = false;
	boolean wasSpace = false;
	
	public CubeTimer (){
		frame = new JFrame ("WP CubeTimer");
		frame.setSize (400,300);
		JPanel pane = new JPanel ();
		JMenuBar menubar = new JMenuBar();
		JMenu file = new JMenu ("File");
		JMenu help = new JMenu ("Help");
		JMenuItem close = new JMenuItem ("Close"); close.addActionListener(this); close.setActionCommand ("Close");
		JMenuItem helpOption = new JMenuItem ("Help"); helpOption.addActionListener(this); helpOption.setActionCommand("help");
		JMenuItem about = new JMenuItem ("About");about.addActionListener (this); about.setActionCommand ("About");
		frame.addKeyListener(this);
		file.add(close);
		help.add(helpOption);
		help.add(about);
		menubar.add(file);
		menubar.add(help);
		frame.setJMenuBar(menubar);
		display = new JLabel ("Press control and space to start/stop the timer.");
		pane.add (display);
		
		frame.add(pane);
		frame.setVisible(true);
	}
	
	public static void main (String[] args){
		CubeTimer ct = new CubeTimer ();
		
	}

	@Override
	public void keyPressed(KeyEvent e) {
		int key = e.getKeyCode();
		if (key == KeyEvent.VK_SPACE){
			space = true;
			System.out.println ("space");
				if (ctrl = true && going == 0){
					timer.start();
					going = 1;
					System.out.println ("space/ CTRL");
				}
				if (ctrl = true && going == 1 && wasCtrl != false && wasSpace != false){
					timer.stop();
				}
		}
		if (key == KeyEvent.VK_CONTROL){
			ctrl = true;
			System.out.println ("CTRL");
			if (space = true && going == 0 && wasCtrl != false && wasSpace != false){
				timer.start();
				going = 1;
				System.out.println ("space/ CTRL");
			}
			else if (space = true && going == 1){
				timer.stop();
			}
		}
		
	}

	@Override
	public void keyReleased(KeyEvent e) {
		// TODO Auto-generated method stub
		int key = e.getKeyCode();
		if (key == KeyEvent.VK_SPACE){
			space = false;
			System.out.println ("Space false");
			//wasSpace = true;
		}
		if (key == KeyEvent.VK_CONTROL){
			ctrl = false;
			System.out.println ("ctrl false");
			//wasCtrl = true;
		}
	}

	@Override
	public void keyTyped(KeyEvent e) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void actionPerformed(ActionEvent e) {
		// TODO Auto-generated method stub
		if ("About".equals(e.getActionCommand ())){
			JFrame aboutFrame = new JFrame ("About");
			aboutFrame.setSize (400,300);
			aboutFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
			JPanel aboutPane = new JPanel ();
			aboutPane.setLayout (new GridLayout (4,1));
			ImageIcon logoImg = new ImageIcon ("LogoBlank.png");
			JLabel logoLabel = new JLabel (logoImg);
			aboutPane.add(logoLabel);
			JLabel version = new JLabel ("Version: " + versionNum, JLabel.CENTER);
			aboutPane.add (version);
			JLabel madeBy = new JLabel ("Made By: Warrior Productions (Adam Balint)", JLabel.CENTER);
			aboutPane.add(madeBy);
			JLabel email = new JLabel ("<html>Contact: <a href=\"WarriorProd@hotmail.com\"> WarriorProd@hotmail.com </a> </html> ", JLabel.CENTER);
			aboutPane.add (email);
			aboutFrame.add(aboutPane);
			aboutFrame.setVisible(true);
		}
		else if ("Close".equals(e.getActionCommand ())){
			frame.dispose();
		}
		else if ("help".equals(e.getActionCommand())){
			helpFrame = new JFrame ("Help");
			helpFrame.setSize (550,150);
			helpFrame.setDefaultCloseOperation (JFrame.DISPOSE_ON_CLOSE);
			JPanel pane = new JPanel ();
			JLabel instruct = new JLabel ("<html> <center>To start the timer: hold down left control and space. When released then the timer starts. <br>" + "<br>" + "To Stop the timer: Press both the left control and spacebar to stop the timer. </center></html>");
			ok = new JButton ("OK"); ok.addActionListener (this);ok.setActionCommand ("helpOK");
			pane.add (instruct);
			pane.add (ok);
			helpFrame.add(pane);
			helpFrame.setVisible(true);	
		}
		
		else if ("helpOK".equals (e.getActionCommand())){
			helpFrame.dispose();
		}
		else {
			time += 1;
			dispTime = time/100;
			display.setText ("" +dispTime);
		}
		
		
	}
	
}
This article has been dead for over six months. Start a new discussion instead.