课件课后练习代码经典案例

JavaOOP贪吃虫游戏——定义Cell类，封装网贪吃虫游戏——随机生成Food与绘制贪吃虫游戏——构建可爬行贪吃虫游戏——实现自动爬行定义类型用于创建贪吃虫的单元格对象以及食物对象,贪吃虫和食物的逻辑关系如图图在舞台上的坐标位置.并且提供构造器方便创建初始化实例,提供属性方法,和便于调试publicpublicclassCellprivateintprivateintpublicCell()publicCell(intx,int{this.x=x;this.y=y;构造器publicCell(Cell{this(cell.x,publicint{returnpublicintgetX()returnpublicvoidsetX(intx)this.x=publicintgetY()returnpublicvoidsetY(inty)this.y=publicStringtoString()returnx+","+创建TestCell,添加mainpublicclassTestCellpublicstaticvoidmain(String[]{Cellhead=newCell(12,8);Cellfood=newCell(30,29);执试结果30,29publicclassCellprivateint privateinty;publicCell()}publicCell(intx,inty)this.x= this.y= 构造器publicCell(Cellcell)this(cell.x, publicintgetX()return publicvoidsetX(intx)this.x= publicintgetY()return publicvoidsetY(inty)this.y= publicStringtoString()returnx+","+ publicclassTestCellpublicstaticvoidmain(String[]args)Cellhead=newCellfood=newCell(30,}}解决随机生成食物问题.在贪吃虫业务功能中每当食物被虫,就需要重新生成一颗食物.创建贪吃虫的舞台,并在舞台上绘制随机生成的食物.JPanelpaint方法用于实现绘制publicclassWormStageextendsJPanel/**节点的大小,以绘制像数为单位publicstaticfinalintCELL_SIZE=/**舞台单元格的列数publicstaticfinalintCELL_COLS=/**舞台单元格的行数publicstaticfinalintCELL_ROWS=publicWormStage()setSize(CELL_COLS*CELL_SIZE,CELL_ROWS*publicvoidpaint(Graphicsg)g.setColor(newColor(35,31,32));g.fillRect(0,0,getWidth(),(food!=null)g.setColor(newColor(255,192,g.fillRect(food.getX()*WormStage.CELL_SIZE,g.setColor(newColor(35,31,g.drawRect(food.getX()**添加成员变量food代表食物的,添加方法randomFood()用于随机生成食物privateCellprivateCellrandomFood()intx;intx=RandomUtils.nextInt(CELL_COLS);y=returnnewCell(x,重写绘制方法paint }publicvoidaction()Scannerscanner=newScanner(System.in);food=randomFood();while(true)foodrepaint();publicstaticvoidmain(String[]args)JFramemain=newJFrame();main.setSize(460,470);Dimensiond=main.setLocation((d.width-main.getWidth())/(d.height-main.getHeight())/WormStagewormStage=newWormStage();intw=main.getContentPane().getWidth();inth=main.getContentPane().getHeight();wormStage.setLocation((w-wormStage.getWidth())(h-wormStage.getHeight())/2);/}执行结果如图图publicclassWormStageextendsJPanelpublicclassWormStageextendsJPanel/**节点的大小,以绘制像数为单位setSize(CELL_COLS*CELL_SIZE,CELL_ROWS*publicvoidaction()Scannerscanner=newScanner(System.in);food=randomFood();while(true){food=randomFood();publicstaticfinal=/**舞台单元格的列数publicstaticfinal=/**舞台单元格的行数publicstaticfinal=privateCellpublicWormStage() privateCellrandomFood()intintx=y=returnnewCell(x, publicvoidpaint(Graphicsg)g.setColor(newColor(35,31,g.fillRect(0,0,getWidth(),if(food!=null)g.setColor(newColor(255,192,g.fillRect(food.getX()* *g.setColor(newColor(35,31,g.drawRect(food.getX()* * publicstaticvoidmain(String[]args)JFramemain=newmain.setSize(460,Dimensiond=main.setLocation((d.width-main.getWidth())/(d.height-main.getHeight())/(h-wormStage.getHeight())/}}WormStagewormStage=newWormStage();intw=inth=wormStage.setLocation((w- /在Cell类中添加paintWormStage类paint方法代码.publicvoidpaint(Graphicsg,Colorb,Colorf)g.fillRect(x*WormStage.CELL_SIZE,y*WormStage.CELL_SIZE,WormStage.CELL_SIZE,WormStage.CELL_SIZE);g.drawRect(x*WormStage.CELL_SIZE,y*WormStage.CELL_SIZE,WormStage.CELL_SIZE,WormStage.CELL_SIZE);publicvoidpaint(Graphicsg)g.setColor(newColor(35,31,g.fillRect(0,0,getWidth(),if(food!=null)food.paint(g,newColor(255,192,newColor(35,31,图定义类Worm表示贪吃类型,贪吃虫包含多个CellpublicclassWorm/**节点数组*/privateCellcells;publicWorm()//WormStage.WORM_LENcells=newfor(inti=0;i<cells.length;{cells[i]=newCell(i,

图爬行(creep)@paramdirectionvoidcreep(intdirection)(direction+currentDirection!=0currentDirection=CellnewHead=(newHead!=null)for(inti=cells.length-1;i>=1;i--{cells[i]=cells[i-cells[0]=}}}图创建类Worm,包含数组类型属性cellspublicclassWorm/**privateCell[]WORM_LEN来自WormStage类中publicWorm()//WormStage.WORM_LENcells=newfor(inti=0;i<cells.length;{cells[i]=newCell(i,/**publicstatic/**方向下*/publicstaticfinalintDIRECTION_UP=intDIRECTION_DOWN=-/**publicstatic/**publicstaticintDIRECTION_LEFT=intDIRECTION_RIGHT=-/**privateintcurrentDirection=privateCellnewHead(intdirection)CellnewHead=null;Cellhead=cells[0];switch(direction){casenewHead=newCell(head.getX(),head.getY()-1);casenewHead=newCell(head.getX(),head.getY()+casenewHead=newCell(head.getX()-1,casenewHead=newCell(head.getX()+1,head.getY());return在Worm类中添加creep()cells[i]=cells[i-}cells[0]=} }爬行(creep)@paramdirectionpublicvoidcreep(intdirection)(direction+currentDirection!=0){currentDirection=CellnewHead=newHead(direction);if(newHead!=null){for(inti=cells.length-1;i>=1;i--)publicvoidpaint(Graphicsg,Colorb,Colorf)for(inti=0;i<cells.length;{cells[i].paint(g,b,重构WormStageworm,worm代表在舞台/**默认贪吃虫的长度publicstaticfinalintWORM_LEN=/**贪吃虫*/privateWormworm;重构WormStage类的绘制方法paint()重构WormStage类的绘制方法paint()wormpublicvoidpaint(Graphicsg)g.setColor(newColor(35,31,32));g.fillRect(0,0,getWidth(),getHeight());if(worm!=null)worm.paint(g,newColor(0,176,240),newColor(35,31,}if(food!=null)food.paint(g,newColor(255,192,0),newColor(35,31,}}重构WormStage类的action()方法增加从控制台字符UDLR,并根据字符控制贪吃虫爬publicvoidaction()//利用控制台输入的UDLR控制蛇的运动Scannerscanner=newScanner(System.in);food=randomFood();worm=newWorm();while(true){Stringcmd=intdirection;if("U".equals(cmd))direction=}elseif{direction=}elseif{direction=}elseif{direction=continue;}}}*publicclassWorm/**方向上publicstaticfinalintDIRECTION_UP=/**方向下publicstaticfinalintDIRECTION_DOWN=-/**方向左publicstaticfinalintDIRECTION_LEFT=/**方向右publicstaticfinalintDIRECTION_RIGHT=-2;/**虫的当前运行方向privateintcurrentDirection=DIRECTION_DOWN;/**节点数组privateCell[]cells;publicWorm()//WormStage.WORM_LENcells=newfor(inti=0;i<cells.length;i++)cells[i]=newCell(i, *爬行(creep)*@paramdirectionpublicvoidcreep(intdirection)(direction+currentDirection!=0)currentDirection=CellnewHead=(newHead!=null)for(inti=cells.length-1;ii--{cells[i]=cells[i-}cells[0]=}}}publicvoidpaint(Graphicsg,Colorb,Color{for(inti=0;i<cells.length;i++)cells[i].paint(g,b,}}privateCellnewHead(intdirection)CellnewHead=Cellhead=switch(direction)casenewHead=newCell(head.getX(),head.getY()-casenewHead=newCell(head.getX(),head.getY()+casenewHead=newCell(head.getX()-1,casenewHead=newCell(head.getX()+}return}}*publicclassWormStageextendsJPanel/**显示单元格大小像素个数publicstaticfinalintCELL_SIZE=/**舞台显示单元格的列数publicstaticfinalintCELL_COLS=/**舞台显示单元格的行数publicstaticfinalintCELL_ROWS=/**默认贪吃虫的长度publicstaticfinalintWORM_LEN=/**贪吃虫privateWorm/**食物privateCellfood;publicWormStage()/**根据行数和列数设置舞台大小setSize(CELL_COLS*CELL_SIZE,CELL_ROWS* publicvoidaction()//利用控制台输入的UDLRScannerscanner=newfood=worm=newwhile(true)Stringcmd=intif("U".equals(cmd))direction=}elseif("D".equals(cmd))direction=}elseif("L".equals(cmd))direction=}elseif("R".equals(cmd))direction=}elsecontinue; privateCellrandomFood()intintx=y=returnnewCell(x, publicvoidpaint(Graphicsg)g.setColor(newColor(35,31,g.fillRect(0,0,getWidth(),if(worm!=null)worm.paint(g,newColor(0,176,240),newColor(35,31,}if(food!=null)food.paint(g,newColor(255,192,newColor(35,31,}}}

publicstaticvoidmain(String[]args){JFramemain=newJFrame();main.setSize(460,470);Dimensiond=main.setLocation((d.width-main.getWidth())/2,(d.height-main.getHeight())/2);WormStagewormStage=newWormStage();intw=main.getContentPane().getWidth();inth=main.getContentPane().getHeight(); wormStage.setLocation((w- /(h-wormStage.getHeight())/}}执行代码得到如下结果,如图图在贪吃虫Worm中增加方法hit*@paramdirection@return如果发生撞击(撞击边缘)就返回true,否则返回publicbooleanhit(intCellnextHeadnewHead(direction);xEL_OLS||nextHead.getY()>=WormStage.CELL_ROWS){returntrue;}returnfalse;//没有发生撞击}publicvoidaction()//利用控制台输入的UDLR控制蛇的运动Scannerscanner=newScanner(System.in);food=randomFood();worm=newWorm();while(true)Stringcmd=intif("U".equals(cmd))direction=}elseif("D".equals(cmd))worm=newWorm();} }direction=}elseif{direction=}elseif{direction}elsecontinue;利用JavaAPI定时器类Timer在java.utilimport到WormStage类中.privateTimertimer=new代表定时器任务,类中包含抽象方法run()run()*publicclassCreepTaskextendsTimerTask/**privateWormStage/**publicCreepTask(WormStagewormStage)this.wormStage=/**run(),*/publicvoidrun(){publicvoidcreepForFood()将定时器任务实例交给定时器timer0200表示间隔200毫秒后再次执行定时任务,方法参考JavaAPI手册:publicvoidaction()worm=newfood=timer.schedule(newCreepTask(this),0,200);重构Worm类,添加重载方法creeppublicvoidcreep()重构Worm@return如果发生撞击就返回true,否则返回publicbooleanreturn重构WormStage类添加属性timerprivateTimertimer=new在WormStage类中添加方法creepForFood/**爬行方法,如果撞头就重新开始publicvoid{worm=newWorm();food=randomFood();}else*publicclassCreepTaskextendsTimerTask/**privateWormStage/**publicCreepTask(WormStagewormStage)this.wormStage=/**run(),*/publicvoidrun(){publicvoidaction()worm=newWorm();food=randomFood();timer.schedule(newCreepTask(this),0,200);完整代码参考(不包含Cell类型,Cell*publicclassCreepTaskextendsTimerTask/**privateWormStage/**publicCreepTask(WormStagewormStage)this.wormStage=}/**实现定时任务的执行方法run(),publicvoidrun(){ *publicclassWorm/**方向上publicstaticfinalintDIRECTION_UP=/**方向下publicstaticfinalintDIRECTION_DOWN=-/**方向左publicstaticfinalintDIRECTION_LEFT=/**方向右publicstaticfinalintDIRECTION_RIGHT=-2;/**虫的当前运行方向privateintcurrentDirection=DIRECTION_DOWN;/**节点数组privateCell[]cells;publicWorm()//WormStage.WORM_LENcells=newfor(inti=0;i<cells.length;i++)cells[i]=newCell(i, * *@paramdirection*@return如果发生撞击就返回true,否则返回publicbooleanhit(intCellnextHead=newHead(direction);//if(nextHead.getX()<0||nextHead.getY()<||nextHead.getX()>=||nextHead.getY()>=WormStage.CELL_ROWS)return}return} **@return如果发生撞击就返回true,否则返回publicbooleanreturn}*爬行(creep)*@paramdirectionpublicvoidcreep(intdirection)if(direction+currentDirection!=0currentDirection=CellnewHead=(newHead!=null)for(inti=cells.length-ii--{cells[i]=cells[i-}cells[0]=}}} publicvoidcreep()}publicvoidpaint(Graphicsg,Colorb,Color{for(inti=0;i<cells.length;i++)cells[i].paint(g,b,}}CellnewHead(intdirection)newHead=head=switch(direction)casenewHead=newCell(head.getX(),head.getY()-casenewHead=newCell(head.getX(),head.getY()+casenewHead=new-casenewHead=new+}return}}*publicclassWormStageextendsJPanel/**显示单元格大小像素个数publicstaticfinalintCELL_SIZE=/**舞台显示单元格的列数publicstaticfinalintCELL_COLS=/**舞台显示单元格的行数publicstaticfinalintCELL_ROWS=/**默认贪吃虫的长度publicstaticfinalintWORM_LEN=/**贪吃虫privateWorm/**食物privateCell/**驱动贪吃虫自动运行的定时器privateTimertimer=newTimer();publicWormStage()setSize(CELL_COLS*CELL_SIZE,CELL_ROWS* publicvoidaction()worm=newfood=timer.schedule(newCreepTask(this),0,