wcanvas.java

塞迪网校J2ME移动应用开发教程的所有源代码.

import javax.microedition.lcdui.*;
import javax.microedition.lcdui.game.*;
import java.util.*;
import java.io.*;
import javax.microedition.media.*;
import javax.microedition.media.control.*;

public class WCanvas extends GameCanvas implements Runnable {
  private Display    display;
  private boolean    sleeping;
  private long       frameDelay;
  private int        inputDelay;
  private TiledLayer backgroundLayer;
  private Sprite     personSprite;
  private Player     musicPlayer;

  public WCanvas(Display d) {
    super(true);
    display = d;

    // Set the frame rate (30 fps)
    frameDelay = 33;

    // Clear the input delay
    inputDelay = 0;
  }
  
  public void start() {
    // Set the canvas as the current screen
    display.setCurrent(this);

    // Create the background tiled layer
    try {
      backgroundLayer = new TiledLayer(16, 16, Image.createImage("/Background.png"), 48, 48);
    }
    catch (IOException e) {
      System.err.println("Failed loading images!");
    }

    // Setup the background tiled layer map
    int[] layerMap = {
      3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,
      3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,
      3, 21, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 22,  3,
      3, 18,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2, 20,  3,
      3, 18,  2,  2,  2,  5, 15, 15, 15, 15, 15, 15,  6,  2, 20,  3,
      3, 18,  2,  2,  2,  7, 10,  1,  1,  1,  1,  1, 16,  2, 20,  3,
      3, 18,  2,  2,  2,  2, 14,  1,  1,  1,  1,  1, 16,  2, 20,  3,
      3, 18,  2,  2,  2,  2,  7, 10,  1,  1,  1,  1, 16,  2, 20,  3,
      3, 18,  2,  2,  2,  2,  2, 14,  1,  1,  1,  1, 16,  2, 20,  3,
      3, 18,  2,  2,  2,  2,  2, 14,  1,  9, 10,  1, 16,  2, 20,  3,
      3, 18,  2,  5, 15,  6,  2, 14,  1, 11, 12,  1, 16,  2, 20,  3,
      3, 18,  2, 14,  1, 16,  2,  7, 13, 13, 13, 13,  8,  2, 20,  3,
      3, 18,  2,  7, 13,  8,  2,  2,  2,  2,  2,  2,  2,  2, 20,  3,
      3, 18,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2, 20,  3,
      3, 23, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 24,  3,
      3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3
    };
    for (int i = 0; i < layerMap.length; i++) {
      int column = i % 16;
      int row = (i - column) / 16;
      backgroundLayer.setCell(column, row, layerMap[i]);
    }
    backgroundLayer.setPosition((getWidth() - backgroundLayer.getWidth()) / 2,
      (getHeight() - backgroundLayer.getHeight()) / 2);

    // Initialize the person sprite
    try {
      personSprite = new Sprite(Image.createImage("/Person.png"), 20, 24);
      personSprite.setPosition((getWidth() - personSprite.getWidth()) / 2,
        (getHeight() - personSprite.getHeight()) / 2);
    }
    catch (IOException e) {
      System.err.println("Failed loading images!");
    }

    // Initialize and start the music player
    try {
      InputStream is = getClass().getResourceAsStream("Music.mid");
      musicPlayer = Manager.createPlayer(is, "audio/midi");
      musicPlayer.prefetch();
      musicPlayer.setLoopCount(-1);
      musicPlayer.start();
    }
    catch (IOException ioe) {
    }
    catch (MediaException me) {
    }

    // Start the animation thread
    sleeping = false;
    Thread t = new Thread(this);
    t.start();
  }
  
  public void stop() {
    // Close the music player
    musicPlayer.close();

    // Stop the animation
    sleeping = true;
  }
  
  public void run() {
    Graphics g = getGraphics();
    
    // The main game loop
    while (!sleeping) {
      update();
      draw(g);
      try {
        Thread.sleep(frameDelay);
      }
      catch (InterruptedException ie) {}
    }
  }

  private void update() {
    // Process user input to move the background layer and animate the person
    if (++inputDelay > 2) {
      int keyState = getKeyStates();
      if ((keyState & LEFT_PRESSED) != 0) {
        backgroundLayer.move(12, 0);
        personSprite.nextFrame();
      }
      else if ((keyState & RIGHT_PRESSED) != 0) {
        backgroundLayer.move(-12, 0);
        personSprite.nextFrame();
      }
      if ((keyState & UP_PRESSED) != 0) {
        backgroundLayer.move(0, 12);
        personSprite.nextFrame();
      }
      else if ((keyState & DOWN_PRESSED) != 0) {
        backgroundLayer.move(0, -12);
        personSprite.nextFrame();
      }
      checkBackgroundBounds(backgroundLayer);

      // Reset the input delay
      inputDelay = 0;
    }
  }

  private void draw(Graphics g) {
    // Draw the background tiled layer
    backgroundLayer.paint(g);
    
    // Draw the person sprite
    personSprite.paint(g);

    // Flush the offscreen graphics buffer
    flushGraphics();
  }

  private void checkBackgroundBounds(TiledLayer background) {
    // Stop the background if necessary
    if (background.getX() > -15)
      background.setPosition(-15, background.getY());
    else if (background.getX() < -572)
      background.setPosition(-572, background.getY());
    if (background.getY() > -25)
      background.setPosition(background.getX(), -25);
    else if (background.getY() < -572)
      background.setPosition(background.getX(), -572);
  }
}