hellocanvas.java

JAVASCRIPT的界面说明JAVASCRIPT的界面说明JAVASCRIPT的界面说明JAVASCRIPT的界面说明

package net.frog_parrot.hello;

import javax.microedition.lcdui.*;
import javax.microedition.lcdui.game.*;

/**
 * This class is the display of the game.
 * 
 * @author Carol Hamer
 */
public class HelloCanvas extends javax.microedition.lcdui.game.GameCanvas {

  //---------------------------------------------------------
  //   fields

  /**
   * a handle to the display.
   */
  Display myDisplay;

  /**
   * whether or not the screen should currently display the 
   * "hello world" message.
   */
  boolean mySayHello = true;

  //-----------------------------------------------------
  //    initialization and game state changes

  /**
   * Constructor merely sets the display.
   */
  public HelloCanvas(Display d) {
    super(false);
    myDisplay = d;
  }

  /**
   * This is called as soon as the application begins.
   */
  void start() {
    myDisplay.setCurrent(this);
    repaint();
  }

  /**
   * toggle the hello message.
   */
  void newHello() {
    mySayHello = !mySayHello;;
    // paint the display
    repaint();
  }

  //-------------------------------------------------------
  //  graphics methods

  /**
   * clear the screen and display the hello world message if appropriate.
   */
  public void paint(Graphics g) {
    int x = g.getClipX();
    int y = g.getClipY();
    int w = g.getClipWidth();
    int h = g.getClipHeight();
    // clear the screen:
    g.setColor(0xffffff);
    g.fillRect(x, y, w, h);
    // display the hello world message if appropriate:.
    if(mySayHello) {
      Font dFont = g.getFont();
      int fontH = dFont.getHeight();
      int fontW = dFont.stringWidth("Hello World!");
      g.setColor(0xffffff);
      g.fillRect((w-fontW)/2 - 1, (h-fontH)/2,
		       fontW + 2, fontH);
      g.setColor(0x00ff0000);
      g.setFont(dFont);
      g.drawString("Hello World!", (w-fontW)/2, (h-fontH)/2,
			 g.TOP|g.LEFT);
    }
  }

}