Canvas for processing key code and commands
/*-------------------------------------------------- * KeyCodes.java * * Canvas for processing key code and commands * * Example from the book: Core J2ME Technology * Copyright John W. Muchow http://www.CoreJ2ME.com * You may use/modify for any non-commercial purpose *-------------------------------------------------*/ import javax.microedition.midlet.*; import javax.microedition.lcdui.*; public class KeyCodes extends MIDlet { private Display display; // The display private KeyCodeCanvas canvas; // Canvas public KeyCodes() { display = Display.getDisplay(this); canvas = new KeyCodeCanvas(this); } protected void startApp() { display.setCurrent( canvas ); } protected void pauseApp() { } protected void destroyApp( boolean unconditional ) { } public void exitMIDlet() { destroyApp(true); notifyDestroyed(); } } /*-------------------------------------------------- * Class KeyCodeCanvas * * Key codes and commands for event handling *-------------------------------------------------*/ class KeyCodeCanvas extends Canvas implements CommandListener { private Command cmExit; // Exit midlet private String keyText = null; // Key code text private KeyCodes midlet; /*-------------------------------------------------- * Constructor *-------------------------------------------------*/ public KeyCodeCanvas(KeyCodes midlet) { this.midlet = midlet; // Create exit command & listen for events cmExit = new Command("Exit", Command.EXIT, 1); addCommand(cmExit); setCommandListener(this); } /*-------------------------------------------------- * Paint the text representing the key code *-------------------------------------------------*/ protected void paint(Graphics g) { // Clear the background (to white) g.setColor(255, 255, 255); g.fillRect(0, 0, getWidth(), getHeight()); // Set color and draw text if (keyText != null) { // Draw with black pen g.setColor(0, 0, 0); // Close to the center g.drawString(keyText, getWidth()/2, getHeight()/2, Graphics.TOP | Graphics.HCENTER); } } /*-------------------------------------------------- * Command event handling *-------------------------------------------------*/ public void commandAction(Command c, Displayable d) { if (c == cmExit) midlet.exitMIDlet(); } /*-------------------------------------------------- * Key code event handling *-------------------------------------------------*/ protected void keyPressed(int keyCode) { keyText = getKeyName(keyCode); repaint(); } }
1. | Key Event Demo | ||
2. | Low-Level Display Canvas:Key Code Example | ||
3. | Event Example 1 | ||
4. | Event Example 2 | ||
5. | Game Key Event | ||
6. | Key MIDlet | ||
7. | Key Event with Canvas | ||
8. | Canvas for processing game actions |