jumpmanager.java

J2ME核心类及MIDlet类 MIDP用户界面对象 图形处理及低级事件处理 多线程编程 I/O及网络编程 数据库RMS编程 浮点数编程 多媒体及GAME API编程 安全、加密及

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

public class JumpManager extends javax.microedition.lcdui.game.LayerManager {

	static int CANVAS_X; // 显示的位置及大小
	static int CANVAS_Y;
	static int DISP_WIDTH;
	static int DISP_HEIGHT;

	Cowboy myCowboy; // 牛仔

	Tumbleweed[] myLeftTumbleweeds; // 从左边来的风火轮
	Tumbleweed[] myRightTumbleweeds;// 从右边来的风火轮

	Grass myGrass; // 草地对象

	boolean myLeft; // 牛仔是否向左

	int myCurrentLeftX; //左边位置

	void setLeft(boolean left) {
		myLeft = left;
	}

	/**
	 * 构造方法
	 */
	public JumpManager(int x, int y, int width, int height) {
		CANVAS_X = x;
		CANVAS_Y = y;
		DISP_WIDTH = width;
		DISP_HEIGHT = height;
		myCurrentLeftX = Grass.CYCLE*Grass.TILE_WIDTH;
		setViewWindow(0, 0, DISP_WIDTH, DISP_HEIGHT);
	}

	/**
	 * 重置
	 */
	void reset() {
		if(myGrass != null) {
			myGrass.reset();
		}
		if(myCowboy != null) {
			myCowboy.reset();
		}
		if(myLeftTumbleweeds != null) {
			for(int i = 0; i < myLeftTumbleweeds.length; i++) {
				myLeftTumbleweeds[i].reset();
			}
		}
		if(myRightTumbleweeds != null) {
			for(int i = 0; i < myRightTumbleweeds.length; i++) {
				myRightTumbleweeds[i].reset();
			}
		}
		myLeft = false;
		myCurrentLeftX = Grass.CYCLE*Grass.TILE_WIDTH;
	}

	/**
	 * 绘制
	 */
	public void paint(Graphics g) throws Exception {
		// 创建牛仔
		if(myCowboy == null) {
			myCowboy = new Cowboy(myCurrentLeftX + DISP_WIDTH/2, 
					DISP_HEIGHT - Cowboy.HEIGHT - 2);
			append(myCowboy);
		}
		// 风火轮
		if(myLeftTumbleweeds == null) {
			myLeftTumbleweeds = new Tumbleweed[2];
			for(int i = 0; i < myLeftTumbleweeds.length; i++) {
				myLeftTumbleweeds[i] = new Tumbleweed(true);
				append(myLeftTumbleweeds[i]);
			}
		}
		if(myRightTumbleweeds == null) {
			myRightTumbleweeds = new Tumbleweed[2];
			for(int i = 0; i < myRightTumbleweeds.length; i++) {
				myRightTumbleweeds[i] = new Tumbleweed(false);
				append(myRightTumbleweeds[i]);
			}
		}
		// 草地
		if(myGrass == null) {
			myGrass = new Grass();
			append(myGrass);
		}
		// 设置视口
		setViewWindow(myCurrentLeftX, 0, DISP_WIDTH, DISP_HEIGHT);
		paint(g, CANVAS_X, CANVAS_Y);
	}

	/**
	 * 如果牛仔到了边缘，则重置所有对象的位置
	 */
	void wrap() {
		if(myCurrentLeftX % (Grass.TILE_WIDTH*Grass.CYCLE) == 0) {
			if(myLeft) {
				myCowboy.move(Grass.TILE_WIDTH*Grass.CYCLE, 0);
				myCurrentLeftX += (Grass.TILE_WIDTH*Grass.CYCLE);
				for(int i = 0; i < myLeftTumbleweeds.length; i++) {
					myLeftTumbleweeds[i].move(Grass.TILE_WIDTH*Grass.CYCLE, 0);
				}
				for(int i = 0; i < myRightTumbleweeds.length; i++) {
					myRightTumbleweeds[i].move(Grass.TILE_WIDTH*Grass.CYCLE, 0);
				}
						} else {
				myCowboy.move(-(Grass.TILE_WIDTH*Grass.CYCLE), 0);
				myCurrentLeftX -= (Grass.TILE_WIDTH*Grass.CYCLE);
				for(int i = 0; i < myLeftTumbleweeds.length; i++) {
					myLeftTumbleweeds[i].move(-Grass.TILE_WIDTH*Grass.CYCLE, 0);
				}
				for(int i = 0; i < myRightTumbleweeds.length; i++) {
					myRightTumbleweeds[i].move(-Grass.TILE_WIDTH*Grass.CYCLE, 0);
				}
			}
		}
	}

	/**
	 * 步进，传入参数是时间，返回值是得分
	 */
	int advance(int gameTicks) {
		int retVal = 0;
		// 改变当前的位置
		if(myLeft) {
			myCurrentLeftX--;
		} else {
			myCurrentLeftX++;
		}
		// 让各个图层对象都步进一点，并获得分数
		myGrass.advance(gameTicks);
		myCowboy.advance(gameTicks, myLeft);
		for(int i = 0; i < myLeftTumbleweeds.length; i++) {
			retVal += myLeftTumbleweeds[i].advance(myCowboy, gameTicks, 
				myLeft, myCurrentLeftX, myCurrentLeftX + DISP_WIDTH);
			retVal -= myCowboy.checkCollision(myLeftTumbleweeds[i]);
		}
		for(int i = 0; i < myLeftTumbleweeds.length; i++) {
			retVal += myRightTumbleweeds[i].advance(myCowboy, gameTicks, 
					 myLeft, myCurrentLeftX, myCurrentLeftX + DISP_WIDTH);
			retVal -= myCowboy.checkCollision(myRightTumbleweeds[i]);
		}
		// 如果需要则进行回转
		wrap();
		return(retVal);
	}

	/**
	 * 跳动
	 */
	void jump() {
		myCowboy.jump();
	}

}