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