microtankcanvas.java

实现了坦克的基本移动和旋转

package MIDP20;
import java.io.IOException;

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

public class MicroTankCanvas extends GameCanvas implements Runnable {
	private boolean mTrucking;

	private MicroTankSprite mTank;

	private TiledLayer mBoard;

	private LayerManager mLayerManager;

	public MicroTankCanvas() throws IOException {
		super(true);

		mTank = createTank();
		mTank.setPosition(0, 24);
		mBoard = createBoard();

		mLayerManager = new LayerManager();
		mLayerManager.append(mTank);
		mLayerManager.append(mBoard);
	}

	private MicroTankSprite createTank() throws IOException {
		Image image = Image.createImage("/tank.png");
		return new MicroTankSprite(image, 32, 32);
	}

	private TiledLayer createBoard() throws IOException {
		Image image = Image.createImage("/board.png");
		TiledLayer tiledLayer = new TiledLayer(10, 10, image, 16, 16);

		int[] map = { 1, 1, 1, 1, 11, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
				0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 9, 0, 0, 0, 0, 0,
				0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 7, 1, 0, 0, 0, 0, 0, 1,
				1, 1, 1, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 11, 0, 0, 0,
				0, 0, 0, 0, 7, 6, 0, 0, 0, 0, 0, 0, 0, 7, 6, 0, 0, 0 };

		for (int i = 0; i < map.length; i++) {
			int column = i % 10;
			int row = (i - column) / 10;
			tiledLayer.setCell(column, row, map[i]);
		}

		return tiledLayer;
	}

	public void start() {
		mTrucking = true;
		Thread t = new Thread(this);
		t.start();
	}

	public void run() {
		Graphics g = getGraphics();

		int timeStep = 80;

		while (mTrucking) {
			long start = System.currentTimeMillis();

			tick();
			input();
			render(g);

			long end = System.currentTimeMillis();
			int duration = (int) (end - start);

			debug(g, duration*100 / timeStep);

			if (duration < timeStep) {
				try {
					Thread.sleep(timeStep - duration);
				} catch (InterruptedException ie) {
					stop();
				}
			}
		}
	}

	private void tick(){
		if (mTank.collidesWith(mBoard, true))
			mTank.undo();
	}

	private void input() {
		int keyStates = getKeyStates();
		if ((keyStates & LEFT_PRESSED) != 0)
			mTank.turn(-1);
		else if ((keyStates & RIGHT_PRESSED) != 0)
			mTank.turn(1);
		else if ((keyStates & UP_PRESSED) != 0)
			mTank.forward(2);
		else if ((keyStates & DOWN_PRESSED) != 0)
			mTank.forward(-2);
	}

	private void render(Graphics g) {
		int w = getWidth();
		int h = getHeight();

		g.setColor(0xffffff);
		g.fillRect(0, 0, w, h);

		int x = (w - 160) / 2;
		int y = (h - 160) / 2;

		mLayerManager.paint(g, x, y);

		g.setColor(0x000000);
		g.drawRect(x, y, 160, 160);

		flushGraphics();
	}

	private void debug(Graphics g, int percent) {
		int w = getWidth();
		int h = getHeight();

		StringBuffer sb = new StringBuffer();
		sb.append(Integer.toString(percent));
		sb.append('%');
		String s = sb.toString();

		Font font = g.getFont();
		int sw = font.stringWidth(s) + 2;
		int sh = font.getHeight();

		// Draw the render capacity.
		g.setColor(0xffffff);
		g.fillRect(w - sw, h - sh, sw, sh);
		g.setColor(0x000000);
		g.drawRect(w - sw, h - sh, sw, sh);
		g.drawString(""+percent+"%",w,h,Graphics.RIGHT|Graphics.BOTTOM);

		flushGraphics();
	}

	public void stop() {
		mTrucking = false;
	}
}