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copied!<p><strong>Disclaimer</strong>: I am not feeling well so this code is horrific, as though.. it too is sick.</p> <p><strong>What I want to happen</strong>: To access DirectInput to obtain a keyboard state, instead of events. That is far beyond the scope of this question though. So we will maintain our own action state.</p> <p>The problem you are having is that you are executing your action within the UI thread. You need to spawn a worker thread and ignore subsequent events until your action is completed.</p> <p>In the example I've given I start a new action when the letter 'a' is pressed or held down. It will not spawn another action until the first action has completed. The action updates a label on the form, displaying how many 'cycles' are left before it has completed. </p> <p>There is also another label that displays how many actions have occurred thus far.</p> <p><strong>Spawning a new action</strong></p> <p>The important part is to let all the UI key events to occur, not blocking in the UI thread causing them to queue up.</p> <pre><code>public void keyPressed(KeyEvent e) { char keyChar = e.getKeyChar(); System.out.println("KeyChar: " + keyChar); // Press a to start an Action if (keyChar == 'a') { if (!mAction.isRunning()) { mTotalActions.setText("Ran " + (++mTotalActionsRan) + " actions."); System.out.println("Starting new Action"); Thread thread = new Thread(new Runnable() { public void run() { mAction.run(); } }); thread.start(); } } } </code></pre> <p><strong>Updates to the UI Thread</strong></p> <p>If your action performs any kind of updates to the User Interface, it will need to use the <code>SwingUtilities.invokeLater</code> method. This method will queue your code to run in the UI thread. You cannot modify the user interface in a thread other than the UI thread. Also, only use SwingUtilities to update UI components. Any calculations, processing, etc that does not invoke methods on a Component, can be done outside the scope of SwingUtilities.invokeLater. </p> <p><strong>Full Code Listing</strong></p> <pre><code>/* * To change this template, choose Tools | Templates * and open the template in the editor. */ package stackoverflow_4589538; import java.awt.event.KeyAdapter; import java.awt.event.KeyEvent; import java.util.Random; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.SwingUtilities; public class Main extends JFrame { private JLabel mActionLabel; private JLabel mTotalActions; private int mTotalActionsRan; private class MyAction { private boolean mIsRunning = false; public void run() { // Make up a random wait cycle time final int cycles = new Random().nextInt(100); for (int i = 0; i < cycles; ++i) { final int currentCycle = i; try { Thread.sleep(100); } catch (InterruptedException ex) { } SwingUtilities.invokeLater(new Runnable() { public void run() { mActionLabel.setText("Cycle " + currentCycle + " of " + cycles); } }); } completed(); } public synchronized void start() { mIsRunning = true; } public synchronized void completed() { mIsRunning = false; } public synchronized boolean isRunning() { return mIsRunning; } } private MyAction mAction = new MyAction(); public Main() { setLayout(null); setBounds(40, 40, 800, 600); setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); addKeyListener(new KeyAdapter() { @Override public void keyPressed(KeyEvent e) { char keyChar = e.getKeyChar(); System.out.println("KeyChar: " + keyChar); // Press A to start an Action if (keyChar == 'a') { if (!mAction.isRunning()) { mTotalActions.setText("Ran " + (++mTotalActionsRan) + " actions."); System.out.println("Starting new Action"); Thread thread = new Thread(new Runnable() { public void run() { mAction.run(); } }); // I had this within the run() method before // but realized that it is possible for another UI event // to occur and spawn another Action before, start() had // occured within the thread mAction.start(); thread.start(); } } } @Override public void keyReleased(KeyEvent e) { } }); mActionLabel = new JLabel(); mActionLabel.setBounds(10, 10, 150, 40); mTotalActions = new JLabel(); mTotalActions.setBounds(10, 50, 150, 40); add(mActionLabel); add(mTotalActions); } public static void main(String[] args) { new Main().setVisible(true); } } </code></pre>

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