package snake;import java.util.*;import javax.microedition.lcdui.*;/** * 貪吃蛇游戲 */public class SnakeCanvas extends Canvas  implements Runnable{    /**存儲貪吃蛇節點坐標,其中第二維下標為0的代表x坐標，第二維下標是1的代表y坐標*/    int[][] snake = new int[200][2];    /**已經使用的節點數量*/    int snakeNum;    /**貪吃蛇運動方向,0代表向上，1代表向下,2代表向左,3代表向右*/    int direction;    /*移動方向*/    /**向上*/    private final int DIRECTION_UP = 0;    /**向下*/    private final int DIRECTION_DOWN = 1;    /**向左*/    private final int DIRECTION_LEFT = 2;    /**向右*/    private final int DIRECTION_RIGHT = 3;    /**游戲區域寬度*/    int width;    /**游戲區域高度*/    int height;    /**蛇身單元寬度*/    private final byte SNAKEWIDTH = 4;    /**是否處于暫停狀態,true代表暫停*/    boolean isPaused = false;    /**是否處于運行狀態,true代表運行*/    boolean isRun = true;    /**時間間隔*/    private final int SLEEP_TIME = 300;    /**食物的X坐標*/    int foodX;    /**食物的Y坐標*/    int foodY;    /**食物的閃爍控制*/    boolean b = true;    /**Random對象*/    Random random = new Random();    public SnakeCanvas() {     //初始化        init();        width = this.getWidth();        height = this.getHeight();        //啟動線程        new Thread(this).start();    }    /**     * 初始化開始數據     */    private void init(){        //初始化節點數量        snakeNum = 7;        //初始化節點數據        for(int i = 0;i < snakeNum;i++){                snake[i][0] = 100 - SNAKEWIDTH * i;                snake[i][1] = 40;        }        //初始化移動方向        direction = DIRECTION_RIGHT;        //初始化食物坐標        foodX = 100;        foodY = 100;    }    protected void paint(Graphics g) {        //清屏        g.setColor(0xffffff);        g.fillRect(0,0,width,height);        g.setColor(0);        //繪制蛇身        for(int i = 0;i < snakeNum;i++){            g.fillRect(snake[i][0],snake[i][1],SNAKEWIDTH,SNAKEWIDTH);        }        //繪制食物        if(b){         g.fillRect(foodX,foodY,SNAKEWIDTH,SNAKEWIDTH);        }    }    private void move(int direction){        //蛇身移動        for(int i = snakeNum - 1;i > 0;i--){            snake[i][0] = snake[i - 1][0];            snake[i][1] = snake[i - 1][1];        }        //第一個單元格移動        switch(direction){        case DIRECTION_UP:            snake[0][1] = snake[0][1] - SNAKEWIDTH;            break;        case DIRECTION_DOWN:            snake[0][1] = snake[0][1] + SNAKEWIDTH;            break;        case DIRECTION_LEFT:            snake[0][0] = snake[0][0] - SNAKEWIDTH;            break;        case DIRECTION_RIGHT:            snake[0][0] = snake[0][0] + SNAKEWIDTH;            break;        }    }    /**     * 吃掉食物，自身增長     */    private void eatFood(){     //判別蛇頭是否和食物重疊     if(snake[0][0] == foodX && snake[0][1] == foodY){      snakeNum++;      generateFood();     }    }    /**     * 產生食物     * 說明：食物的坐標必須位于屏幕內，且不能和蛇身重合     */    private void generateFood(){     while(true){      foodX = Math.abs(random.nextInt() % (width - SNAKEWIDTH + 1))                        / SNAKEWIDTH * SNAKEWIDTH;      foodY = Math.abs(random.nextInt() % (height - SNAKEWIDTH + 1))                        / SNAKEWIDTH * SNAKEWIDTH;      boolean b = true;      for(int i = 0;i < snakeNum;i++){       if(foodX == snake[i][0] && snake[i][1] == foodY){        b = false;        break;       }      }      if(b){       break;      }     }    }    /**     * 判斷游戲是否結束     * 結束條件：     *        1、蛇頭超出邊界     *        2、蛇頭碰到自身     */    private boolean isGameOver(){     //邊界判別     if(snake[0][0] < 0 || snake[0][0] > (width - SNAKEWIDTH) ||        snake[0][1] < 0 || snake[0][1] > (height - SNAKEWIDTH)){      return true;     }     //碰到自身     for(int i = 4;i < snakeNum;i++){      if(snake[0][0] == snake[i][0]         && snake[0][1] == snake[i][1]){       return true;      }     }     return false;    } /**  * 事件處理  */    public void keyPressed(int keyCode){        int action = this.getGameAction(keyCode);        //改變方向        switch(action){        case UP:            if(direction != DIRECTION_DOWN){                direction = DIRECTION_UP;            }            break;        case DOWN:            if(direction != DIRECTION_UP){                direction = DIRECTION_DOWN;            }            break;        case LEFT:            if(direction != DIRECTION_RIGHT){                direction = DIRECTION_LEFT;            }            break;        case RIGHT:            if(direction != DIRECTION_LEFT){                direction = DIRECTION_RIGHT;            }            break;        case FIRE:         //暫停和繼續            isPaused = !isPaused;            break;        }    } /**  * 線程方法  * 使用精確延時  */    public void run(){        try{            while (isRun) {             //開始時間             long start = System.currentTimeMillis();                if(!isPaused){                    //吃食物                    eatFood();                    //移動                    move(direction);                    //結束游戲                    if(isGameOver()){                     break;                    }                    //控制閃爍                    b = !b;                }                //重新繪制                repaint();                long end = System.currentTimeMillis();                //延時                if(end - start < SLEEP_TIME){                 Thread.sleep(SLEEP_TIME - (end - start));                }            }        }catch(Exception e){}    }}