Java Blog Buch

Zusammenfassung

Movable Interface

package de.jbb.j2me.ll;

public interface Movable {

  void movePoint(int keyCode);
}

RepeatHelper

package de.jbb.j2me.ll;

public class RepeatHelper implements Runnable {

  private int keyCode = -1;
  private int waitingTime;
  private boolean repeat;

  private Movable movable;

  public RepeatHelper(Movable movable, int waitingTime) {
    this.movable = movable;
    this.waitingTime = waitingTime;
  }

  public void run() {
    while (true) {
      if (repeat) {
        movable.movePoint(keyCode);
      }
      try {
        Thread.sleep(waitingTime);
      }
      catch (InterruptedException ie) {
        ie.printStackTrace();
      }
    }
  }

  public void setKeyCode(int keyCode) {
    this.keyCode = keyCode;
    repeat = true;
  }

  public void stopRepeating() {
    repeat = false;
  }
}

ActionCanvas

package de.jbb.j2me.ll;

import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Graphics;

public class ActionCanvas extends Canvas implements Movable {

  private boolean drawRed = true;
  private int pointSize = 10;
  private int x = 0;
  private int y = 0;
  private int pointStep = 5;

  private RepeatHelper repeater;

  public ActionCanvas() {
    repeater = new RepeatHelper(this, 40);
    new Thread(repeater).start();
  }

  protected void paint(Graphics g) {

    g.setColor(0, 0, 0);
    g.fillRect(0, 0, getWidth(), getHeight());
    if (drawRed) {
      g.setColor(255, 0, 0);
    }
    else {
      g.setColor(255, 255, 255);
    }
    g.fillArc(x, y, pointSize, pointSize, 0, 360);
   }

  public void movePoint(int keyCode) {

    switch (getGameAction(keyCode)) {
    case LEFT:
      x -= pointStep;
      break;
    case RIGHT:
      x += pointStep;
      break;
    case UP:
      y -= pointStep;
      break;
    case DOWN:
      y += pointStep;
      break;
    case FIRE:
      drawRed = !drawRed;
      break;
    default:
      switch (keyCode) {
      case KEY_NUM2:
        y -= pointStep;
        break;
      case KEY_NUM4:
        x -= pointStep;
        break;
      case KEY_NUM6:
        x += pointStep;
        break;
      case KEY_NUM8:
        y += pointStep;
        break;
      case KEY_NUM5:
        drawRed = !drawRed;
      }
    }
    if (x < 0) {
      x = 0;
    }
    else if (x + pointSize > getWidth()) {
      x = getWidth() - pointSize;
    }
    else if (y < 0) {
      y = 0;
    }
    else if (y + pointSize > getHeight()) {
      y = getHeight() - pointSize;
    }
    repaint();
  }

  private void setBallTo(int x, int y) {

    if (x < 0) {
      x = 0;
    }
    if (x + pointSize > getWidth()) {
      x = getWidth() - pointSize;
    }
    if (y < 0) {
      y = 0;
    }
    if (y + pointSize > getHeight()) {
      y = getHeight() - pointSize;
    }
    this.x = x;
    this.y = y;
    repaint();
  }

  protected void pointerDragged(int x, int y) {
    setBallTo(x - pointSize / 2, y - pointSize / 2);
  }

  protected void pointerPressed(int x, int y) {
    setBallTo(x - pointSize / 2, y - pointSize / 2);
  }

  protected void keyPressed(int keyCode) {
    movePoint(keyCode);
    if (getGameAction(keyCode) != FIRE && keyCode != KEY_NUM5) {
      repeater.setKeyCode(keyCode);
    }
  }

  protected void keyReleased(int keyCode) {
    repeater.stopRepeating();
  }
}

ActionMIDlet

package de.jbb.j2me.ll;

import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.midlet.MIDlet;

public class ActionMIDlet extends MIDlet implements CommandListener {

  private boolean first = true;

  private Command exit;
  private Display display;
  private ActionCanvas canvas;

  public void commandAction(Command c, Displayable d) {

    if (exit.equals(c)) {
      destroyApp(false);
    }
  }

  protected void startApp() {

    if (first) {
      canvas = new ActionCanvas();
      exit = new Command("Beenden", Command.EXIT, 0);
      display = Display.getDisplay(this);

      canvas.setTitle("Action Canvas");
      canvas.addCommand(exit);
      canvas.setCommandListener(this);
    }
    display.setCurrent(canvas);
  }

  protected void destroyApp(boolean unconditional) {
    notifyDestroyed();
  }

  protected void pauseApp() {}
}