Android优美代码赏析:Snake游戏分析

1.运行时图

 

2.软件架构图 

 

3.eclipse生成资源定义 

按上一篇导入Snake Sample代码后，eclipse将根据Snake\res下的资源生成\Snake\gen\com\example\android\snake\R.java

 

Snake\res\layout\snake_layout.xml为游戏界面布局文件

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent" //继承系统设置
    android:layout_height="match_parent">
    
    <com.example.android.snake.SnakeView
     android:id="@+id/snake" //定义app id为snake
        android:layout_width="match_parent"

//继承系统设置


                android:layout_height="match_parent"
                tileSize="24"
                />
    
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    

        <TextView
         android:id="@+id/text" //定义test view id为 text
            android:text="@string/snake_layout_text_text"
            android:visibility="visible"
            android:layout_width="wrap_content" 

//继承系统设置


            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:gravity="center_horizontal"
            android:textColor="#ff8888ff"
            android:textSize="24"/>
    </RelativeLayout>

</FrameLayout>  

 生成的R.java为：(根据资源文件的目录来分析代码即可)

package com.example.android.snake;

public final class R {
    public static final class attr {

        public static final int tileSize=0x7f010000;
    }

    public static final class drawable {
        public static final int greenstar=0x7f020000;
        public static final int redstar=0x7f020001;
        public static final int yellowstar=0x7f020002;
    }

    public static final class id {
        public static final int snake=0x7f050000;
        public static final int text=0x7f050001;
    }

    public static final class layout {
        public static final int snake_layout=0x7f030000;
    }

    public static final class string {
        public static final int mode_lose_prefix=0x7f040002;
        public static final int mode_lose_suffix=0x7f040003;
        public static final int mode_pause=0x7f040001;

        public static final int mode_ready=0x7f040000;
        public static final int snake_layout_text_text=0x7f040004;
    }
    public static final class styleable {

        public static final int[] TileView = {
            0x7f010000
        };

        public static final int TileView_tileSize = 0;
    };

} 

 4.基础状态说明： 

    1)游戏状态

//状态
    private int mMode = READY;
    public static final int PAUSE = 0;
    public static final int READY = 1;
    public static final int RUNNING = 2;
    public static final int LOSE = 3;
//状态设置函数 public void SnakView::setMode(int newMode);
    
       //方向
    private int mDirection = NORTH;
    private int mNextDirection = NORTH;
    private static final int NORTH = 1;
    private static final int SOUTH = 2;
    private static final int EAST = 3;
    private static final int WEST = 4;
//方向设置函数：public boolean SnakView::onKeyDown(int keyCode, KeyEvent msg);

     //其他
    private long mScore = 0;
    private long mMoveDelay = 600;
  (mScore记录分数，mMoveDelay为每次移动的时间间距)

    private long mLastMove;  

   2)显示点状态(绘制指定点)

      //状态定义,0为不画图片
    private static final int RED_STAR = 1;
    private static final int YELLOW_STAR = 2;
    private static final int GREEN_STAR = 3;

 

 

    //导入资源 

    privatevoid initSnakeView() {
        setFocusable(true);

        Resources r = this.getContext().getResources();

       resetTiles(4);
        loadTile(RED_STAR, r.getDrawable(R.drawable.redstar));
        loadTile(YELLOW_STAR, r.getDrawable(R.drawable.yellowstar));
        loadTile(GREEN_STAR, r.getDrawable(R.drawable.greenstar));
        
    }  

 //绘制点

SnakeView::updateSnake -> TextView::setTile
调用TextView::onDraw时逐个去画，

View::invalidate激活上述onDraw 

 绘图的实现是通过一个redraw的定时来实现的

mRedrawHandler.sleep(mMoveDelay); 

 此redraw的定义：

    /**
     * Create a simple handler that we can use to cause animation to happen.  We
     * set ourselves as a target and we can use the sleep()
     * function to cause an update/invalidate to occur at a later date.
     */


    private RefreshHandler mRedrawHandler = new RefreshHandler();

    class RefreshHandler extends Handler {

        @Override
        public void handleMessage(Message msg) {
            SnakeView.this.update();
            SnakeView.this.invalidate();
        }


        public void sleep(long delayMillis) {
            this.removeMessages(0);
            sendMessageDelayed(obtainMessage(0), delayMillis);
        }

   }; 

  3)界面布局与状态初始化

布局文件位于:  Snake/res/layput/snake_layout.xml

初始化：

(1)程序onCreate时：

setContentView(R.layout.snake_layout);

(2)构造SnakeView类时：initSnakeView();

4)按键处理

public boolean SnakView::onKeyDown(int keyCode, KeyEvent msg);

    

5.逻辑实现：(待完成)

1)随机苹果的生成：

initNewGame ->addRandomApple

2)Snake的移动

根据每一次移动的mMoveDelay 也为redraw的间距来分析

(1)绘画：update -》 updateSnake

(2)吃Apple动作

(3)程序暂停与撞墙死亡

作者：Anpher Zhang QQ:275000205

转载请注明出处：http://zhangsufeng.cnblogs.com/ 

求一份Android或嵌入式linux开发工作。

附录：部分内容摘自http://xusaomaiss.iteye.com/blog/393135