Android中使用代码截图的各种方法总结

向右看齐 2022-08-07 01:41 217阅读 0赞

目录[(?)][Link 1][\[+\]][Link 1]

1.  [1基于Android SDK的截屏方法][1_Android SDK]
2.  [2 基于Android ddmlib进行截屏][2 _Android ddmlib]
3.  [3 Android本地编程Native Programming读取framebuffer][3 Android_Native Programming_framebuffer]
4.  [4 利用TakeScreenShotService截图][4 _TakeScreenShotService]
5.  [Android源码中对组合键的捕获][Android]
6.  [Android源码中调用屏幕截图的接口][Android 1]

## 1,基于Android SDK的截屏方法 ##

(1)主要就是利用SDK提供的View.getDrawingCache()方法。网上已经有很多的实例了。首先创建一个android project，然后进行Layout，画一个按键（res/layout/main.xml）：

<table style=""> 
 <tbody style=""> 
 <tr style=""> 
 <td style=""> 
 <div style=""> 
 <div style=""> 
 
 <code style="">&lt;?</code> 
 <code style="">xml</code> 
 <code style="">version</code> 
 <code style="">=</code> 
 <code style="">"1.0"</code> 
 <code style="">encoding</code> 
 <code style="">=</code> 
 <code style="">"utf-8"</code> 
 <code style="">?&gt;</code> 
 </div> 
 <div style=""> 
 
 <code style="">&lt;</code> 
 <code style="">LinearLayout</code> 
 <code style="">xmlns:android</code> 
 <code style="">=</code> 
 <code style="">"<a href="http://schemas.android.com/apk/res/android" style="" rel="nofollow">http://schemas.android.com/apk/res/android</a>"</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">android:orientation</code> 
 <code style="">=</code> 
 <code style="">"vertical"</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">android:layout_width</code> 
 <code style="">=</code> 
 <code style="">"fill_parent"</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">android:layout_height</code> 
 <code style="">=</code> 
 <code style="">"fill_parent"</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">&gt;</code> 
 </div> 
 <div style=""> 
 
 <code style="">&lt;</code> 
 <code style="">TextView</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">android:layout_width</code> 
 <code style="">=</code> 
 <code style="">"fill_parent"</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">android:layout_height</code> 
 <code style="">=</code> 
 <code style="">"wrap_content"</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">android:text</code> 
 <code style="">=</code> 
 <code style="">"@string/hello"</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">/&gt;</code> 
 </div> 
 <div style=""> 
 
 <code style="">&lt;</code> 
 <code style="">Button</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;</code> 
 <code style="">android:text</code> 
 <code style="">=</code> 
 <code style="">"NiceButton"</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;</code> 
 <code style="">android:id</code> 
 <code style="">=</code> 
 <code style="">"@+id/my_button"</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;</code> 
 <code style="">android:layout_width</code> 
 <code style="">=</code> 
 <code style="">"fill_parent"</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;</code> 
 <code style="">android:layout_height</code> 
 <code style="">=</code> 
 <code style="">"wrap_content"</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;</code> 
 <code style="">android:layout_alignParentBottom</code> 
 <code style="">=</code> 
 <code style="">"true"</code> 
 <code style="">&gt;&lt;/</code> 
 <code style="">Button</code> 
 <code style="">&gt;</code> 
 </div> 
 <div style=""> 
 
 <code style="">&lt;/</code> 
 <code style="">LinearLayout</code> 
 <code style="">&gt;</code> 
 </div> 
 </div> </td> 
 </tr> 
 </tbody> 
</table>

HelloAndroid.java实现代码为：

<table style=""> 
 <tbody style=""> 
 <tr style=""> 
 <td style=""> 
 <div style=""> 
 <div style=""> 
 
 <code style="">package</code> 
 <code style="">com.example.helloandroid;</code> 
 </div> 
 <div style=""> 
 &nbsp; 
 </div> 
 <div style=""> 
 
 <code style="">import</code> 
 <code style="">java.io.FileOutputStream;</code> 
 </div> 
 <div style=""> 
 
 <code style="">import</code> 
 <code style="">java.text.SimpleDateFormat;</code> 
 </div> 
 <div style=""> 
 
 <code style="">import</code> 
 <code style="">java.util.Date;</code> 
 </div> 
 <div style=""> 
 
 <code style="">import</code> 
 <code style="">java.util.Locale;</code> 
 </div> 
 <div style=""> 
 &nbsp; 
 </div> 
 <div style=""> 
 
 <code style="">import</code> 
 <code style="">android.app.Activity;</code> 
 </div> 
 <div style=""> 
 
 <code style="">import</code> 
 <code style="">android.graphics.Bitmap;</code> 
 </div> 
 <div style=""> 
 
 <code style="">import</code> 
 <code style="">android.os.Bundle;</code> 
 </div> 
 <div style=""> 
 
 <code style="">import</code> 
 <code style="">android.view.View;</code> 
 </div> 
 <div style=""> 
 
 <code style="">import</code> 
 <code style="">android.view.View.OnClickListener;</code> 
 </div> 
 <div style=""> 
 
 <code style="">import</code> 
 <code style="">android.widget.Button;</code> 
 </div> 
 <div style=""> 
 &nbsp; 
 </div> 
 <div style=""> 
 
 <code style="">public</code> 
 <code style="">class</code> 
 <code style="">HelloAndroid</code> 
 <code style="">extends</code> 
 <code style="">Activity { </code> 
 </div> 
 <div style=""> 
 &nbsp; 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;</code> 
 <code style="">private</code> 
 <code style="">Button button;</code> 
 </div> 
 <div style=""> 
 &nbsp; 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;</code> 
 <code style="">/** Called when the activity is first created. */</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;</code> 
 <code style="">@Override</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;</code> 
 <code style="">public</code> 
 <code style="">void</code> 
 <code style="">onCreate(Bundle savedInstanceState) { </code> 
 </div> 
 <div style=""> 
 &nbsp; 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">super</code> 
 <code style="">.onCreate(savedInstanceState);</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">this</code> 
 <code style="">.setContentView(R.layout.main);</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">this</code> 
 <code style="">.button = (Button) </code> 
 <code style="">this</code> 
 <code style="">.findViewById(R.id.my_button);</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">this</code> 
 <code style="">.button.setOnClickListener(</code> 
 <code style="">new</code> 
 <code style="">OnClickListener() { </code> 
 </div> 
 <div style=""> 
 &nbsp; 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">public</code> 
 <code style="">void</code> 
 <code style="">onClick(View v) { </code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">SimpleDateFormat sdf = </code> 
 <code style="">new</code> 
 <code style="">SimpleDateFormat(</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">"yyyy-MM-dd_HH-mm-ss"</code> 
 <code style="">, Locale.US);</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">String fname = </code> 
 <code style="">"/sdcard/"</code> 
 <code style="">+ sdf.format(</code> 
 <code style="">new</code> 
 <code style="">Date()) + </code> 
 <code style="">".png"</code> 
 <code style="">;</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">View view = v.getRootView();</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">view.setDrawingCacheEnabled(</code> 
 <code style="">true</code> 
 <code style="">);</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">view.buildDrawingCache();</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">Bitmap bitmap = view.getDrawingCache();</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">if</code> 
 <code style="">(bitmap != </code> 
 <code style="">null</code> 
 <code style="">) { </code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">System.out.println(</code> 
 <code style="">"bitmap got!"</code> 
 <code style="">);</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">try</code> 
 <code style="">{ </code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">FileOutputStream out = </code> 
 <code style="">new</code> 
 <code style="">FileOutputStream(fname);</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">bitmap.compress(Bitmap.CompressFormat.PNG,</code> 
 <code style="">100</code> 
 <code style="">, out);</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">System.out.println(</code> 
 <code style="">"file "</code> 
 <code style=""> + fname + </code> 
 <code style="">"output done."</code> 
 <code style="">);</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">}</code> 
 <code style="">catch</code> 
 <code style="">(Exception e) { </code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">e.printStackTrace();</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">}</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">}</code> 
 <code style="">else</code> 
 <code style="">{ </code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">System.out.println(</code> 
 <code style="">"bitmap is NULL!"</code> 
 <code style="">);</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">}</code> 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">}</code> 
 </div> 
 <div style=""> 
 &nbsp; 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">});</code> 
 </div> 
 <div style=""> 
 &nbsp; 
 </div> 
 <div style=""> 
 
 <code style="">&nbsp;&nbsp;</code> 
 <code style="">}</code> 
 </div> 
 <div style=""> 
 
 <code style="">}</code> 
 </div> 
 </div> </td> 
 </tr> 
 </tbody> 
</table>

这个代码会在按下app中按键的时候自动在手机的/sdcard/目录下生成一个时间戳命名的png截屏文件。

这种截屏有一个问题，就是只能截到一部分，比如电池指示部分就截不出来了。

(2)在APK中调用“adb shell screencap -pfilepath” 命令

该命令读取系统的framebuffer，需要获得系统权限：

> （1）. 在AndroidManifest.xml文件中添加
> 
> < uses-permission android:name = "android.permission.READ\_FRAME\_BUFFER" />
> 
> （2）. 修改APK为系统权限，将APK放到源码中编译， 修改Android.mk
> 
>  LOCAL\_CERTIFICATE := platform
> 
> 
>

publicvoid takeScreenShot(){ 
           String mSavedPath = Environment.getExternalStorageDirectory()+File. separator + "screenshot.png" ; 
        try {                     
                  Runtime. getRuntime().exec("screencap -p " + mSavedPath); 
           } catch (Exception e) { 
                  e.printStackTrace(); 
           }

(3).利用系统的API，实现Screenshot,这部分代码是系统隐藏的，需要在源码下编译，

1).修改Android.mk， 添加系统权限

LOCAL\_CERTIFICATE := platform

2).修改AndroidManifest.xml 文件，添加

权限

< uses-permission android:name = "android.permission.READ\_FRAME\_BUFFER" />

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 </div> </td> 
 <td style=""> 
 <div style=""> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">public</code>&nbsp; 
 <code style="">boolean</code>&nbsp; 
 <code style="">takeScreenShot(String imagePath){ </code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code>&nbsp; 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code>&nbsp; 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code>&nbsp; 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">if</code> 
 <code style="">(imagePath.equals(</code> 
 <code style="">""</code>&nbsp; 
 <code style="">)){ </code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">imagePath = Environment.getExternalStorageDirectory()+File. separator+</code> 
 <code style="">"Screenshot.png"</code>&nbsp; 
 <code style="">;</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">}</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code>&nbsp; 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">Bitmap mScreenBitmap;</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">WindowManager mWindowManager;</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">DisplayMetrics mDisplayMetrics;</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">Display mDisplay;</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code>&nbsp; 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">mWindowManager = (WindowManager) mcontext.getSystemService(Context.WINDOW_SERVICE);</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">mDisplay = mWindowManager.getDefaultDisplay();</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">mDisplayMetrics =&nbsp;</code> 
 <code style="">new</code>&nbsp; 
 <code style="">DisplayMetrics();</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">mDisplay.getRealMetrics(mDisplayMetrics);</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code>&nbsp; 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">float</code> 
 <code style="">[] dims = {mDisplayMetrics.widthPixels , mDisplayMetrics.heightPixels };</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">mScreenBitmap = Surface. screenshot((</code> 
 <code style="">int</code> 
 <code style="">) dims[</code> 
 <code style="">0</code> 
 <code style="">], (&nbsp;</code> 
 <code style="">int</code> 
 <code style="">) dims[</code> 
 <code style="">1</code> 
 <code style="">]);</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code>&nbsp; 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">if</code>&nbsp; 
 <code style="">(mScreenBitmap ==&nbsp;</code> 
 <code style="">null</code> 
 <code style="">) {&nbsp;&nbsp;</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">return</code>&nbsp; 
 <code style="">false</code>&nbsp; 
 <code style="">;</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">}</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code>&nbsp; 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">try</code>&nbsp; 
 <code style="">{ </code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">FileOutputStream out =&nbsp;</code> 
 <code style="">new</code>&nbsp; 
 <code style="">FileOutputStream(imagePath);</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">mScreenBitmap.compress(Bitmap.CompressFormat. PNG,&nbsp;</code> 
 <code style="">100</code> 
 <code style="">, out);</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code>&nbsp; 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">}&nbsp;</code> 
 <code style="">catch</code>&nbsp; 
 <code style="">(Exception e) { </code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code>&nbsp; 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code>&nbsp; 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">return</code>&nbsp; 
 <code style="">false</code>&nbsp; 
 <code style="">;</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">}&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code>&nbsp; 
 </div> 
 <div style=""> 
 <code style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
 <code style="">return</code>&nbsp; 
 <code style="">true</code>&nbsp; 
 <code style="">;</code> 
 </div> 
 <div style=""> 
 <code style="">}</code> 
 </div> 
 <div> 
 <code style=""> </code> 
 </div> 
 </div> </td> 
 </tr> 
 </tbody> 
</table>

## 2 基于Android ddmlib进行截屏 ##

**\[java\]** [ view plain][Link 1] [copy][Link 1] [print][Link 1] [?][Link 1]

1. public class ScreenShot \{  
2.  private BufferedImage image = null;  
3.  /\*\* 
4.   \* @param args 
5.   \*/  
6.  public static void main(String\[\] args) \{  
7.   // TODO Auto-generated method stub  
8.   AndroidDebugBridge.init(false); //  
9.   ScreenShot screenshot = new ScreenShot();  
10.   IDevice device = screenshot.getDevice();  
11.     
12.   for (int i = 0; i < 10; i++) \{  
13.    Date date=new Date();  
14.    SimpleDateFormat df=new SimpleDateFormat("MM-dd-HH-mm-ss");   
15.    String nowTime = df.format(date);  
16.    screenshot.getScreenShot(device, "Robotium" + nowTime);  
17.    try \{  
18.     Thread.sleep(1000);  
19.    \} catch (InterruptedException e) \{  
20.     // TODO Auto-generated catch block  
21.     e.printStackTrace();  
22.    \}  
23.   \}  
24.  \}  
25.   
26.    
27.  public void getScreenShot(IDevice device,String filename) \{  
28.   RawImage rawScreen = null;  
29.   try \{  
30.    rawScreen = device.getScreenshot();  
31.   \} catch (TimeoutException e) \{  
32.    // TODO Auto-generated catch block  
33.    e.printStackTrace();  
34.   \} catch (AdbCommandRejectedException e) \{  
35.    // TODO Auto-generated catch block  
36.    e.printStackTrace();  
37.   \} catch (IOException e) \{  
38.    // TODO Auto-generated catch block  
39.    e.printStackTrace();  
40.   \}  
41.   if (rawScreen != null) \{  
42.    Boolean landscape = false;  
43.    int width2 = landscape ? rawScreen.height : rawScreen.width;  
44.    int height2 = landscape ? rawScreen.width : rawScreen.height;  
45.    if (image == null) \{  
46.     image = new BufferedImage(width2, height2,  
47.       BufferedImage.TYPE\_INT\_RGB);  
48.    \} else \{  
49.     if (image.getHeight() != height2 || image.getWidth() != width2) \{  
50.      image = new BufferedImage(width2, height2,  
51.        BufferedImage.TYPE\_INT\_RGB);  
52.     \}  
53.    \}  
54.    int index = 0;  
55.    int indexInc = rawScreen.bpp >> 3;  
56.    for (int y = 0; y < rawScreen.height; y++) \{  
57.     for (int x = 0; x < rawScreen.width; x++, index += indexInc) \{  
58.      int value = rawScreen.getARGB(index);  
59.      if (landscape)  
60.       image.setRGB(y, rawScreen.width - x - 1, value);  
61.      else  
62.       image.setRGB(x, y, value);  
63.     \}  
64.    \}  
65.    try \{  
66.     ImageIO.write((RenderedImage) image, "PNG", new File("D:/"  
67.       + filename + ".jpg"));  
68.    \} catch (IOException e) \{  
69.     // TODO Auto-generated catch block  
70.     e.printStackTrace();  
71.    \}  
72.   \}  
73.  \}  
74.   
75.  /\*\* 
76.   \* 获取得到device对象 
77.   \* @return 
78.   \*/  
79.  private IDevice getDevice()\{  
80.   IDevice device;  
81.   AndroidDebugBridge bridge = AndroidDebugBridge  
82.     .createBridge("adb", true);//如果代码有问题请查看API，修改此处的参数值试一下  
83.   waitDevicesList(bridge);  
84.   IDevice devices\[\] = bridge.getDevices();  
85.   device = devices\[0\];  
86.   return device;  
87.  \}  
88.    
89.  /\*\* 
90.   \* 等待查找device 
91.   \* @param bridge 
92.   \*/  
93.  private void waitDevicesList(AndroidDebugBridge bridge) \{  
94.   int count = 0;  
95.   while (bridge.hasInitialDeviceList() == false) \{  
96.    try \{  
97.     Thread.sleep(500);   
98.     count++;  
99.    \} catch (InterruptedException e) \{  
100.    \}  
101.    if (count > 240) \{  
102.     System.err.print("等待获取设备超时");  
103.     break;  
104.    \}  
105.   \}  
106.  \}

public class ScreenShot {
 private BufferedImage image = null;
 /**
 * @param args
 */
 public static void main(String[] args) {
 // TODO Auto-generated method stub
 AndroidDebugBridge.init(false); //
 ScreenShot screenshot = new ScreenShot();
 IDevice device = screenshot.getDevice();
 
 for (int i = 0; i < 10; i++) {
 Date date=new Date();
 SimpleDateFormat df=new SimpleDateFormat("MM-dd-HH-mm-ss"); 
 String nowTime = df.format(date);
 screenshot.getScreenShot(device, "Robotium" + nowTime);
 try {
 Thread.sleep(1000);
 } catch (InterruptedException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }
 }
 }
 
 
 public void getScreenShot(IDevice device,String filename) {
 RawImage rawScreen = null;
 try {
 rawScreen = device.getScreenshot();
 } catch (TimeoutException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 } catch (AdbCommandRejectedException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 } catch (IOException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }
 if (rawScreen != null) {
 Boolean landscape = false;
 int width2 = landscape ? rawScreen.height : rawScreen.width;
 int height2 = landscape ? rawScreen.width : rawScreen.height;
 if (image == null) {
 image = new BufferedImage(width2, height2,
 BufferedImage.TYPE_INT_RGB);
 } else {
 if (image.getHeight() != height2 || image.getWidth() != width2) {
 image = new BufferedImage(width2, height2,
 BufferedImage.TYPE_INT_RGB);
 }
 }
 int index = 0;
 int indexInc = rawScreen.bpp >> 3;
 for (int y = 0; y < rawScreen.height; y++) {
 for (int x = 0; x < rawScreen.width; x++, index += indexInc) {
 int value = rawScreen.getARGB(index);
 if (landscape)
 image.setRGB(y, rawScreen.width - x - 1, value);
 else
 image.setRGB(x, y, value);
 }
 }
 try {
 ImageIO.write((RenderedImage) image, "PNG", new File("D:/"
 + filename + ".jpg"));
 } catch (IOException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }
 }
 }
 
 /**
 * 获取得到device对象
 * @return
 */
 private IDevice getDevice(){
 IDevice device;
 AndroidDebugBridge bridge = AndroidDebugBridge
 .createBridge("adb", true);//如果代码有问题请查看API，修改此处的参数值试一下
 waitDevicesList(bridge);
 IDevice devices[] = bridge.getDevices();
 device = devices[0];
 return device;
 }
 
 /**
 * 等待查找device
 * @param bridge
 */
 private void waitDevicesList(AndroidDebugBridge bridge) {
 int count = 0;
 while (bridge.hasInitialDeviceList() == false) {
 try {
 Thread.sleep(500); 
 count++;
 } catch (InterruptedException e) {
 }
 if (count > 240) {
 System.err.print("等待获取设备超时");
 break;
 }
 }
 }

## 3 Android本地编程（Native Programming）读取framebuffer ##

(1)命令行，框架的截屏功能是通过framebuffer来实现的，所以我们先来介绍一下framebuffer。

**framebuffer介绍**  
帧缓冲（framebuffer）是Linux为显示设备提供的一个接口，把显存抽象后的一种设备，他允许上层应用程序在图形模式下直接对显示缓冲区进行 读写操作。这种操作是抽象的，统一的。用户不必关心物理显存的位置、换页机制等等具体细节。这些都是由Framebuffer设备驱动来完成的。  
Linux FrameBuffer 本质上只是提供了对图形设备的硬件抽象，在开发者看来，FrameBuffer 是一块显示缓存，往显示缓存中写入特定格式的数据就意味着向屏幕输出内容。所以说FrameBuffer就是一块白板。例如对于初始化为16 位色的FrameBuffer 来说， FrameBuffer中的两个字节代表屏幕上一个点，从上到下，从左至右，屏幕位置与内存地址是顺序的线性关系。  
帧缓存有个地址，是在内存里。我们通过不停的向frame buffer中写入数据， 显示控制器就自动的从frame buffer中取数据并显示出来。全部的图形都共享内存中同一个帧缓存。

**Android截屏实现思路**  
Android系统是基于Linux内核的，所以也存在framebuffer这个设备，我们要实现截屏的话只要能获取到framebuffer中的数据，然后把数据转换成图片就可以了，android中的framebuffer数据是存放在 **/dev/graphics/fb0** 文件中的，所以我们只需要来获取这个文件的数据就可以得到当前屏幕的内容。  
现在我们的测试代码运行时候是通过RC(remote controller)方式来运行被测应用的，那就需要在PC机上来访问模拟器或者真机上的framebuffer数据，这个的话可以通过android的ADB命令来实现。

具体实现 
 
 
/\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* 
  \* 
  \*   ScreenShot.java 
  \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*/ 
import java.awt.image.BufferedImage; 
import java.io.ByteArrayOutputStream; 
import java.io.DataInput; 
import java.io.EOFException; 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.IOException; 
import java.io.InputStream; 
import javax.imageio.ImageIO; 
import org.openqa.selenium.OutputType; 
import org.openqa.selenium.internal.Base64Encoder; 
import com.google.common.io.Closeables; 
import com.google.common.io.LittleEndianDataInputStream; 
 
/\*\* 
 \*/ 
public class ScreenShot \{ 
 
    /\*\* 
     \* @param args 
     \* @throws InterruptedException  
     \*/ 
    public static void main(String\[\] args) throws InterruptedException \{     
        try \{ 
            //分辨率大小，后续可以通过代码来获取到当前的分辨率 
            int xResolution = 320; 
            int yResolution = 480; 
            //执行adb命令，把framebuffer中内容保存到fb1文件中 
             Runtime.getRuntime().exec("adb pull /dev/graphics/fb0 C:/fb1"); 
             //等待几秒保证framebuffer中的数据都被保存下来，如果没有保存完成进行读取操作会有IO异常 
             Thread.sleep(15000); 
             //读取文件中的数据 
             InputStream in = (InputStream)new FileInputStream("C:/fb1"); 
             DataInput frameBuffer = new LittleEndianDataInputStream(in); 
              
             BufferedImage screenImage = new BufferedImage( 
                     xResolution, yResolution, BufferedImage.TYPE\_INT\_ARGB); 
                 int\[\] oneLine = new int\[xResolution\]; 
                for (int y = 0; y < yResolution; y++) \{ 
                    //从frameBuffer中计算出rgb值 
                    convertToRgba32(frameBuffer, oneLine); 
                    //把rgb值设置到image对象中 
                    screenImage.setRGB(0, y, xResolution, 1, oneLine, 0, xResolution); 
                \} 
                Closeables.closeQuietly(in); 
                 
                ByteArrayOutputStream rawPngStream = new ByteArrayOutputStream(); 
                try \{ 
                      if (!ImageIO.write(screenImage, "png", rawPngStream)) \{ 
                        throw new RuntimeException( 
                            "This Java environment does not support converting to PNG."); 
                      \} 
                    \} catch (IOException exception) \{ 
                      // This should never happen because rawPngStream is an in-memory stream. 
                     System.out.println("IOException=" + exception); 
                    \} 
                byte\[\] rawPngBytes = rawPngStream.toByteArray(); 
                String base64Png = new Base64Encoder().encode(rawPngBytes); 
                 
                File screenshot = OutputType.FILE.convertFromBase64Png(base64Png); 
                System.out.println("screenshot==" + screenshot.toString()); 
                screenshot.renameTo(new File("C:\\\\screenshottemp.png")); 
                 
        \} catch (IOException e) \{ 
            // TODO Auto-generated catch block 
            e.printStackTrace(); 
            System.out.println(e); 
        \} 
    \} 
     
     
    public static void convertToRgba32(DataInput frameBuffer, int\[\] into) \{ 
        try \{ 
            for (int x = 0; x < into.length; x++) \{ 
                try\{ 
                int rgb = frameBuffer.readShort() & 0xffff; 
                int red = rgb >> 11; 
                red = (red << 3) | (red >> 2); 
                int green = (rgb >> 5) & 63; 
                green = (green << 2) | (green >> 4); 
                int blue = rgb & 31; 
                blue = (blue << 3) | (blue >> 2); 
                into\[x\] = 0xff000000 | (red << 16) | (green << 8) | blue; 
                \}catch (EOFException e)\{ 
                    System.out.println("EOFException=" + e); 
                \} 
              \} 
        \} catch (IOException exception) \{ 
            System.out.println("convertToRgba32Exception=" + exception); 
      \} 
    \} 
     
\}

（2）

**\[java\]** [ view plain][Link 1] [copy][Link 1] [print][Link 1] [?][Link 1]

1. 首先是直接移植SystemUI的代码，实现截图效果，这部分的代码就不贴出来了，直接去下载代码吧， 关键的代码没有几句，最最主要的是：Surface.screenshot()，请看代码吧。  
2.   
3. \[java\]  
4. <SPAN style="FONT-SIZE: 16px">package org.winplus.ss;   
5.    
6. import java.io.File;   
7. import java.io.FileNotFoundException;   
8. import java.io.FileOutputStream;   
9. import java.io.IOException;   
10. import java.text.SimpleDateFormat;   
11. import java.util.Date;   
12.    
13. import android.app.Activity;   
14. import android.content.Context;   
15. import android.graphics.Bitmap;   
16. import android.graphics.Canvas;   
17. import android.graphics.Matrix;   
18. import android.os.Bundle;   
19. import android.util.DisplayMetrics;   
20. import android.util.Log;   
21. import android.view.Display;   
22. import android.view.Surface;   
23. import android.view.WindowManager;   
24. import android.os.SystemProperties;   
25.    
26. public class SimpleScreenshotActivity extends Activity \{   
27.    
28.     private Display mDisplay;   
29.     private WindowManager mWindowManager;   
30.     private DisplayMetrics mDisplayMetrics;   
31.     private Bitmap mScreenBitmap;   
32.     private Matrix mDisplayMatrix;   
33.    
34.     @Override   
35.     public void onCreate(Bundle savedInstanceState) \{   
36.         super.onCreate(savedInstanceState);   
37.         setContentView(R.layout.main);   
38.    
39.         new Thread(new Runnable() \{   
40.    
41.             @Override   
42.             public void run() \{   
43.                 takeScreenshot();   
44.    
45.             \}   
46.         \}).start();   
47.     \}   
48.    
49.     private float getDegreesForRotation(int value) \{   
50.         switch (value) \{   
51.         case Surface.ROTATION\_90:   
52.             return 360f - 90f;   
53.         case Surface.ROTATION\_180:   
54.             return 360f - 180f;   
55.         case Surface.ROTATION\_270:   
56.             return 360f - 270f;   
57.         \}   
58.         return 0f;   
59.     \}   
60.    
61.     private void takeScreenshot() \{   
62.         mWindowManager = (WindowManager) getSystemService(Context.WINDOW\_SERVICE);   
63.         mDisplay = mWindowManager.getDefaultDisplay();   
64.         mDisplayMetrics = new DisplayMetrics();   
65.         mDisplay.getRealMetrics(mDisplayMetrics);   
66.         mDisplayMatrix = new Matrix();   
67.         float\[\] dims = \{ mDisplayMetrics.widthPixels,   
68.                 mDisplayMetrics.heightPixels \};   
69.    
70.         int value = mDisplay.getRotation();   
71.         String hwRotation = SystemProperties.get("ro.sf.hwrotation", "0");   
72.         if (hwRotation.equals("270") || hwRotation.equals("90")) \{   
73.             value = (value + 3) % 4;   
74.         \}   
75.         float degrees = getDegreesForRotation(value);   
76.    
77.         boolean requiresRotation = (degrees > 0);   
78.         if (requiresRotation) \{   
79.             // Get the dimensions of the device in its native orientation    
80.             mDisplayMatrix.reset();   
81.             mDisplayMatrix.preRotate(-degrees);   
82.             mDisplayMatrix.mapPoints(dims);   
83.    
84.             dims\[0\] = Math.abs(dims\[0\]);   
85.             dims\[1\] = Math.abs(dims\[1\]);   
86.         \}   
87.    
88.         mScreenBitmap = Surface.screenshot((int) dims\[0\], (int) dims\[1\]);   
89.    
90.         if (requiresRotation) \{   
91.             // Rotate the screenshot to the current orientation    
92.             Bitmap ss = Bitmap.createBitmap(mDisplayMetrics.widthPixels,   
93.                     mDisplayMetrics.heightPixels, Bitmap.Config.ARGB\_8888);   
94.             Canvas c = new Canvas(ss);   
95.             c.translate(ss.getWidth() / 2, ss.getHeight() / 2);   
96.             c.rotate(degrees);   
97.             c.translate(-dims\[0\] / 2, -dims\[1\] / 2);   
98.             c.drawBitmap(mScreenBitmap, 0, 0, null);   
99.             c.setBitmap(null);   
100.             mScreenBitmap = ss;   
101.         \}   
102.    
103.         // If we couldn't take the screenshot, notify the user    
104.         if (mScreenBitmap == null) \{   
105.             return;   
106.         \}   
107.    
108.         // Optimizations    
109.         mScreenBitmap.setHasAlpha(false);   
110.         mScreenBitmap.prepareToDraw();   
111.            
112.         try \{   
113.             saveBitmap(mScreenBitmap);   
114.         \} catch (IOException e) \{   
115.             System.out.println(e.getMessage());   
116.         \}   
117.     \}   
118.    
119.     public void saveBitmap(Bitmap bitmap) throws IOException \{   
120.         String imageDate = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss")   
121.                 .format(new Date(System.currentTimeMillis()));   
122.         File file = new File("/mnt/sdcard/Pictures/"\+imageDate+".png");   
123.         if(!file.exists())\{   
124.             file.createNewFile();   
125.         \}   
126.         FileOutputStream out;   
127.         try \{   
128.             out = new FileOutputStream(file);   
129.             if (bitmap.compress(Bitmap.CompressFormat.PNG, 70, out)) \{   
130.                 out.flush();   
131.                 out.close();   
132.             \}   
133.         \} catch (FileNotFoundException e) \{   
134.             e.printStackTrace();   
135.         \} catch (IOException e) \{   
136.             e.printStackTrace();   
137.         \}   
138.     \}   
139. \}   
140.    
141.   
142. package org.winplus.ss;  
143.   
144. import java.io.File;  
145. import java.io.FileNotFoundException;  
146. import java.io.FileOutputStream;  
147. import java.io.IOException;  
148. import java.text.SimpleDateFormat;  
149. import java.util.Date;  
150.   
151. import android.app.Activity;  
152. import android.content.Context;  
153. import android.graphics.Bitmap;  
154. import android.graphics.Canvas;  
155. import android.graphics.Matrix;  
156. import android.os.Bundle;  
157. import android.util.DisplayMetrics;  
158. import android.util.Log;  
159. import android.view.Display;  
160. import android.view.Surface;  
161. import android.view.WindowManager;  
162. import android.os.SystemProperties;  
163.   
164. public class SimpleScreenshotActivity extends Activity \{  
165.   
166.  private Display mDisplay;  
167.  private WindowManager mWindowManager;  
168.  private DisplayMetrics mDisplayMetrics;  
169.  private Bitmap mScreenBitmap;  
170.  private Matrix mDisplayMatrix;  
171.   
172.  @Override  
173.  public void onCreate(Bundle savedInstanceState) \{  
174.   super.onCreate(savedInstanceState);  
175.   setContentView(R.layout.main);  
176.   
177.   new Thread(new Runnable() \{  
178.   
179.    @Override  
180.    public void run() \{  
181.     takeScreenshot();  
182.   
183.    \}  
184.   \}).start();  
185.  \}  
186.   
187.  private float getDegreesForRotation(int value) \{  
188.   switch (value) \{  
189.   case Surface.ROTATION\_90:  
190.    return 360f - 90f;  
191.   case Surface.ROTATION\_180:  
192.    return 360f - 180f;  
193.   case Surface.ROTATION\_270:  
194.    return 360f - 270f;  
195.   \}  
196.   return 0f;  
197.  \}  
198.   
199.  private void takeScreenshot() \{  
200.   mWindowManager = (WindowManager) getSystemService(Context.WINDOW\_SERVICE);  
201.   mDisplay = mWindowManager.getDefaultDisplay();  
202.   mDisplayMetrics = new DisplayMetrics();  
203.   mDisplay.getRealMetrics(mDisplayMetrics);  
204.   mDisplayMatrix = new Matrix();  
205.   float\[\] dims = \{ mDisplayMetrics.widthPixels,  
206.     mDisplayMetrics.heightPixels \};  
207.   
208.   int value = mDisplay.getRotation();  
209.   String hwRotation = SystemProperties.get("ro.sf.hwrotation", "0");  
210.   if (hwRotation.equals("270") || hwRotation.equals("90")) \{  
211.    value = (value + 3) % 4;  
212.   \}  
213.   float degrees = getDegreesForRotation(value);  
214.   
215.   boolean requiresRotation = (degrees > 0);  
216.   if (requiresRotation) \{  
217.    // Get the dimensions of the device in its native orientation  
218.    mDisplayMatrix.reset();  
219.    mDisplayMatrix.preRotate(-degrees);  
220.    mDisplayMatrix.mapPoints(dims);  
221.   
222.    dims\[0\] = Math.abs(dims\[0\]);  
223.    dims\[1\] = Math.abs(dims\[1\]);  
224.   \}  
225.   
226.   mScreenBitmap = Surface.screenshot((int) dims\[0\], (int) dims\[1\]);  
227.   
228.   if (requiresRotation) \{  
229.             // Rotate the screenshot to the current orientation  
230.             Bitmap ss = Bitmap.createBitmap(mDisplayMetrics.widthPixels,  
231.                     mDisplayMetrics.heightPixels, Bitmap.Config.ARGB\_8888);  
232.             Canvas c = new Canvas(ss);  
233.             c.translate(ss.getWidth() / 2, ss.getHeight() / 2);  
234.             c.rotate(degrees);  
235.             c.translate(-dims\[0\] / 2, -dims\[1\] / 2);  
236.             c.drawBitmap(mScreenBitmap, 0, 0, null);  
237.             c.setBitmap(null);  
238.             mScreenBitmap = ss;  
239.         \}  
240.   
241.         // If we couldn't take the screenshot, notify the user  
242.         if (mScreenBitmap == null) \{  
243.             return;  
244.         \}  
245.   
246.         // Optimizations  
247.         mScreenBitmap.setHasAlpha(false);  
248.         mScreenBitmap.prepareToDraw();  
249.          
250.   try \{  
251.    saveBitmap(mScreenBitmap);  
252.   \} catch (IOException e) \{  
253.    System.out.println(e.getMessage());  
254.   \}  
255.  \}  
256.   
257.  public void saveBitmap(Bitmap bitmap) throws IOException \{  
258.   String imageDate = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss")  
259.     .format(new Date(System.currentTimeMillis()));  
260.   File file = new File("/mnt/sdcard/Pictures/"\+imageDate+".png");  
261.   if(!file.exists())\{  
262.    file.createNewFile();  
263.   \}  
264.   FileOutputStream out;  
265.   try \{  
266.    out = new FileOutputStream(file);  
267.    if (bitmap.compress(Bitmap.CompressFormat.PNG, 70, out)) \{  
268.     out.flush();  
269.     out.close();  
270.    \}  
271.   \} catch (FileNotFoundException e) \{  
272.    e.printStackTrace();  
273.   \} catch (IOException e) \{  
274.    e.printStackTrace();  
275.   \}  
276.  \}  
277. \}  
278.   
279. PS：1、需要在AndroidManifest.xml中加入代码：android:sharedUserId="android.uid.system"  
280.   
281.          2、由于调用了@hide的API，所以编译得时候请使用makefile编译。或者通过在Eclipse中添加Jar文件通过编译。  
282.   
283.          3、此代码只在Android4.0中使用过，2.3的就没去做测试了。

首先是直接移植SystemUI的代码，实现截图效果，这部分的代码就不贴出来了，直接去下载代码吧， 关键的代码没有几句，最最主要的是：Surface.screenshot()，请看代码吧。
 
 [java]
 package org.winplus.ss; 
 
 import java.io.File; 
 import java.io.FileNotFoundException; 
 import java.io.FileOutputStream; 
 import java.io.IOException; 
 import java.text.SimpleDateFormat; 
 import java.util.Date; 
 
 import android.app.Activity; 
 import android.content.Context; 
 import android.graphics.Bitmap; 
 import android.graphics.Canvas; 
 import android.graphics.Matrix; 
 import android.os.Bundle; 
 import android.util.DisplayMetrics; 
 import android.util.Log; 
 import android.view.Display; 
 import android.view.Surface; 
 import android.view.WindowManager; 
 import android.os.SystemProperties; 
 
 public class SimpleScreenshotActivity extends Activity { 
 
 private Display mDisplay; 
 private WindowManager mWindowManager; 
 private DisplayMetrics mDisplayMetrics; 
 private Bitmap mScreenBitmap; 
 private Matrix mDisplayMatrix; 
 
 @Override 
 public void onCreate(Bundle savedInstanceState) { 
 super.onCreate(savedInstanceState); 
 setContentView(R.layout.main); 
 
 new Thread(new Runnable() { 
 
 @Override 
 public void run() { 
 takeScreenshot(); 
 
 } 
 }).start(); 
 } 
 
 private float getDegreesForRotation(int value) { 
 switch (value) { 
 case Surface.ROTATION_90: 
 return 360f - 90f; 
 case Surface.ROTATION_180: 
 return 360f - 180f; 
 case Surface.ROTATION_270: 
 return 360f - 270f; 
 } 
 return 0f; 
 } 
 
 private void takeScreenshot() { 
 mWindowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE); 
 mDisplay = mWindowManager.getDefaultDisplay(); 
 mDisplayMetrics = new DisplayMetrics(); 
 mDisplay.getRealMetrics(mDisplayMetrics); 
 mDisplayMatrix = new Matrix(); 
 float[] dims = { mDisplayMetrics.widthPixels, 
 mDisplayMetrics.heightPixels }; 
 
 int value = mDisplay.getRotation(); 
 String hwRotation = SystemProperties.get("ro.sf.hwrotation", "0"); 
 if (hwRotation.equals("270") || hwRotation.equals("90")) { 
 value = (value + 3) % 4; 
 } 
 float degrees = getDegreesForRotation(value); 
 
 boolean requiresRotation = (degrees > 0); 
 if (requiresRotation) { 
 // Get the dimensions of the device in its native orientation 
 mDisplayMatrix.reset(); 
 mDisplayMatrix.preRotate(-degrees); 
 mDisplayMatrix.mapPoints(dims); 
 
 dims[0] = Math.abs(dims[0]); 
 dims[1] = Math.abs(dims[1]); 
 } 
 
 mScreenBitmap = Surface.screenshot((int) dims[0], (int) dims[1]); 
 
 if (requiresRotation) { 
 // Rotate the screenshot to the current orientation 
 Bitmap ss = Bitmap.createBitmap(mDisplayMetrics.widthPixels, 
 mDisplayMetrics.heightPixels, Bitmap.Config.ARGB_8888); 
 Canvas c = new Canvas(ss); 
 c.translate(ss.getWidth() / 2, ss.getHeight() / 2); 
 c.rotate(degrees); 
 c.translate(-dims[0] / 2, -dims[1] / 2); 
 c.drawBitmap(mScreenBitmap, 0, 0, null); 
 c.setBitmap(null); 
 mScreenBitmap = ss; 
 } 
 
 // If we couldn't take the screenshot, notify the user 
 if (mScreenBitmap == null) { 
 return; 
 } 
 
 // Optimizations 
 mScreenBitmap.setHasAlpha(false); 
 mScreenBitmap.prepareToDraw(); 
 
 try { 
 saveBitmap(mScreenBitmap); 
 } catch (IOException e) { 
 System.out.println(e.getMessage()); 
 } 
 } 
 
 public void saveBitmap(Bitmap bitmap) throws IOException { 
 String imageDate = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss") 
 .format(new Date(System.currentTimeMillis())); 
 File file = new File("/mnt/sdcard/Pictures/"+imageDate+".png"); 
 if(!file.exists()){ 
 file.createNewFile(); 
 } 
 FileOutputStream out; 
 try { 
 out = new FileOutputStream(file); 
 if (bitmap.compress(Bitmap.CompressFormat.PNG, 70, out)) { 
 out.flush(); 
 out.close(); 
 } 
 } catch (FileNotFoundException e) { 
 e.printStackTrace(); 
 } catch (IOException e) { 
 e.printStackTrace(); 
 } 
 } 
 } 
 
 
 package org.winplus.ss;
 
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.text.SimpleDateFormat;
 import java.util.Date;
 
 import android.app.Activity;
 import android.content.Context;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
 import android.graphics.Matrix;
 import android.os.Bundle;
 import android.util.DisplayMetrics;
 import android.util.Log;
 import android.view.Display;
 import android.view.Surface;
 import android.view.WindowManager;
 import android.os.SystemProperties;
 
 public class SimpleScreenshotActivity extends Activity {
 
 private Display mDisplay;
 private WindowManager mWindowManager;
 private DisplayMetrics mDisplayMetrics;
 private Bitmap mScreenBitmap;
 private Matrix mDisplayMatrix;
 
 @Override
 public void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.main);
 
 new Thread(new Runnable() {
 
 @Override
 public void run() {
 takeScreenshot();
 
 }
 }).start();
 }
 
 private float getDegreesForRotation(int value) {
 switch (value) {
 case Surface.ROTATION_90:
 return 360f - 90f;
 case Surface.ROTATION_180:
 return 360f - 180f;
 case Surface.ROTATION_270:
 return 360f - 270f;
 }
 return 0f;
 }
 
 private void takeScreenshot() {
 mWindowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
 mDisplay = mWindowManager.getDefaultDisplay();
 mDisplayMetrics = new DisplayMetrics();
 mDisplay.getRealMetrics(mDisplayMetrics);
 mDisplayMatrix = new Matrix();
 float[] dims = { mDisplayMetrics.widthPixels,
 mDisplayMetrics.heightPixels };
 
 int value = mDisplay.getRotation();
 String hwRotation = SystemProperties.get("ro.sf.hwrotation", "0");
 if (hwRotation.equals("270") || hwRotation.equals("90")) {
 value = (value + 3) % 4;
 }
 float degrees = getDegreesForRotation(value);
 
 boolean requiresRotation = (degrees > 0);
 if (requiresRotation) {
 // Get the dimensions of the device in its native orientation
 mDisplayMatrix.reset();
 mDisplayMatrix.preRotate(-degrees);
 mDisplayMatrix.mapPoints(dims);
 
 dims[0] = Math.abs(dims[0]);
 dims[1] = Math.abs(dims[1]);
 }
 
 mScreenBitmap = Surface.screenshot((int) dims[0], (int) dims[1]);
 
 if (requiresRotation) {
 // Rotate the screenshot to the current orientation
 Bitmap ss = Bitmap.createBitmap(mDisplayMetrics.widthPixels,
 mDisplayMetrics.heightPixels, Bitmap.Config.ARGB_8888);
 Canvas c = new Canvas(ss);
 c.translate(ss.getWidth() / 2, ss.getHeight() / 2);
 c.rotate(degrees);
 c.translate(-dims[0] / 2, -dims[1] / 2);
 c.drawBitmap(mScreenBitmap, 0, 0, null);
 c.setBitmap(null);
 mScreenBitmap = ss;
 }
 
 // If we couldn't take the screenshot, notify the user
 if (mScreenBitmap == null) {
 return;
 }
 
 // Optimizations
 mScreenBitmap.setHasAlpha(false);
 mScreenBitmap.prepareToDraw();
 
 try {
 saveBitmap(mScreenBitmap);
 } catch (IOException e) {
 System.out.println(e.getMessage());
 }
 }
 
 public void saveBitmap(Bitmap bitmap) throws IOException {
 String imageDate = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss")
 .format(new Date(System.currentTimeMillis()));
 File file = new File("/mnt/sdcard/Pictures/"+imageDate+".png");
 if(!file.exists()){
 file.createNewFile();
 }
 FileOutputStream out;
 try {
 out = new FileOutputStream(file);
 if (bitmap.compress(Bitmap.CompressFormat.PNG, 70, out)) {
 out.flush();
 out.close();
 }
 } catch (FileNotFoundException e) {
 e.printStackTrace();
 } catch (IOException e) {
 e.printStackTrace();
 }
 }
 }
 
 PS：1、需要在AndroidManifest.xml中加入代码：android:sharedUserId="android.uid.system"
 
 2、由于调用了@hide的API，所以编译得时候请使用makefile编译。或者通过在Eclipse中添加Jar文件通过编译。
 
 3、此代码只在Android4.0中使用过，2.3的就没去做测试了。

## 4 利用TakeScreenShotService截图 ##

Android手机一般都自带有手机屏幕截图的功能：在手机任何界面（当然手机要是开机点亮状态），通过按组合键，屏幕闪一下，然后咔嚓一声，截图的照片会保存到当前手机的图库中，真是一个不错的功能！

以我手头的测试手机为例，是同时按电源键+音量下键来实现截屏，苹果手机则是电源键 + HOME键，小米手机是菜单键+音量下键，而HTC一般是按住电源键再按左下角的“主页”键。那么Android源码中使用组合键是如何实现屏幕截图功能呢？前段时间由于工作的原因仔细看了一下，这两天不忙，便把相关的知识点串联起来整理一下，分下面两部分简单分析下实现流程：

## Android源码中对组合键的捕获。 ##

Android源码中对按键的捕获位于文件PhoneWindowManager.java（alps\\frameworks\\base\\policy\\src\\com\\android\\internal\\policy\\impl）中，这个类处理所有的键盘输入事件，其中函数interceptKeyBeforeQueueing（）会对常用的按键做特殊处理。以我手头的测试机为例，是同时按电源键和音量下键来截屏，那么在这个函数中我们会看到这么两段代码：

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 </div> </td> 
 <td style=""> 
 <div style=""> 
 <pre style="">.......
 case KeyEvent.KEYCODE_VOLUME_DOWN:
 case KeyEvent.KEYCODE_VOLUME_UP:
 case KeyEvent.KEYCODE_VOLUME_MUTE: {
 
 if (keyCode == KeyEvent.KEYCODE_VOLUME_DOWN) {
 
 if (down) {
 
 if (isScreenOn &amp;&amp; !mVolumeDownKeyTriggered
 &amp;&amp; (event.getFlags() &amp; KeyEvent.FLAG_FALLBACK) == 0) {
 
 mVolumeDownKeyTriggered = true;
 mVolumeDownKeyTime = event.getDownTime();
 mVolumeDownKeyConsumedByScreenshotChord = false;
 cancelPendingPowerKeyAction();
 interceptScreenshotChord();
 }
 } else {
 
 mVolumeDownKeyTriggered = false;
 cancelPendingScreenshotChordAction();
 }
......

case KeyEvent.KEYCODE_POWER: {
 
 result &amp;= ~ACTION_PASS_TO_USER;
 if (down) {
 
 if (isScreenOn &amp;&amp; !mPowerKeyTriggered
 &amp;&amp; (event.getFlags() &amp; KeyEvent.FLAG_FALLBACK) == 0) {
 
 mPowerKeyTriggered = true;
 mPowerKeyTime = event.getDownTime();
 interceptScreenshotChord();
 }
......
</pre> 
 </div> </td> 
 </tr> 
 </tbody> 
</table>

可以看到正是在这里（响应Down事件）捕获是否按了音量下键和电源键的，而且两个地方都会进入函数interceptScreenshotChord()中，那么接下来看看这个函数干了什么工作：

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 </div> </td> 
 <td style=""> 
 <div style=""> 
 <pre style=""> private void interceptScreenshotChord() {
 
 if (mVolumeDownKeyTriggered &amp;&amp; mPowerKeyTriggered &amp;&amp; !mVolumeUpKeyTriggered) {
 
 final long now = SystemClock.uptimeMillis();
 if (now &lt;= mVolumeDownKeyTime + SCREENSHOT_CHORD_DEBOUNCE_DELAY_MILLIS
 &amp;&amp; now &lt;= mPowerKeyTime + SCREENSHOT_CHORD_DEBOUNCE_DELAY_MILLIS) {
 
 mVolumeDownKeyConsumedByScreenshotChord = true;
 cancelPendingPowerKeyAction();

mHandler.postDelayed(mScreenshotChordLongPress,
 ViewConfiguration.getGlobalActionKeyTimeout());
 }
 }
 }
</pre> 
 </div> </td> 
 </tr> 
 </tbody> 
</table>

在这个函数中，用两个布尔变量判断是否同时按了音量下键和电源键后，再计算两个按键响应Down事件之间的时间差不超过150毫秒，也就认为是同时按了这两个键后，算是真正的捕获到屏幕截屏的组合键。

**附言**：文件PhoneWindowManager.java类是拦截键盘消息的处理类，在此类中还有对home键、返回键等好多按键的处理。

## Android源码中调用屏幕截图的接口。 ##

捕获到组合键后，我们再看看android源码中是如何调用屏幕截图的函数接口。在上面的函数interceptScreenshotChord中我们看到用handler判断长按组合键500毫秒之后，会进入如下函数：

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 </div> </td> 
 <td style=""> 
 <div style=""> 
 <pre style=""> private final Runnable mScreenshotChordLongPress = new Runnable() {
 
 public void run() {
 
 takeScreenshot();
 }
 };
</pre> 
 </div> </td> 
 </tr> 
 </tbody> 
</table>

在这里启动了一个线程来完成截屏的功能，接着看函数takeScreenshot():

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 </div> </td> 
 <td style=""> 
 <div style=""> 
 <pre style="">private void takeScreenshot() {
 
 synchronized (mScreenshotLock) {
 
 if (mScreenshotConnection != null) {
 
 return;
 }
 ComponentName cn = new ComponentName("com.android.systemui",
 "com.android.systemui.screenshot.TakeScreenshotService");
 Intent intent = new Intent();
 intent.setComponent(cn);
 ServiceConnection conn = new ServiceConnection() {
 
 @Override
 public void onServiceConnected(ComponentName name, IBinder service) {
 
 synchronized (mScreenshotLock) {
 
 if (mScreenshotConnection != this) {
 
 return;
 }
 Messenger messenger = new Messenger(service);
 Message msg = Message.obtain(null, 1);
 final ServiceConnection myConn = this;
 Handler h = new Handler(mHandler.getLooper()) {
 
 @Override
 public void handleMessage(Message msg) {
 
 synchronized (mScreenshotLock) {
 
 if (mScreenshotConnection == myConn) {
 
 mContext.unbindService(mScreenshotConnection);
 mScreenshotConnection = null;
 mHandler.removeCallbacks(mScreenshotTimeout);
 }
 }
 }
 };
 msg.replyTo = new Messenger(h);
 msg.arg1 = msg.arg2 = 0;
 if (mStatusBar != null &amp;&amp; mStatusBar.isVisibleLw())
 msg.arg1 = 1;
 if (mNavigationBar != null &amp;&amp; mNavigationBar.isVisibleLw())
 msg.arg2 = 1;
 try {
 
 messenger.send(msg);
 } catch (RemoteException e) {
 
 }
 }
 }
 @Override
 public void onServiceDisconnected(ComponentName name) {}
 };
 if (mContext.bindService(intent, conn, Context.BIND_AUTO_CREATE)) {
 
 mScreenshotConnection = conn;
 mHandler.postDelayed(mScreenshotTimeout, 10000);
 }
 }
 }
</pre> 
 </div> </td> 
 </tr> 
 </tbody> 
</table>

可以看到这个函数使用AIDL绑定了service服务到"com.android.systemui.screenshot.TakeScreenshotService"，注意在service连接成功时，对message的msg.arg1和msg.arg2两个参数的赋值。其中在mScreenshotTimeout中对服务service做了超时处理。接着我们找到实现这个服务service的类TakeScreenshotService，看看其实现的流程：

private static GlobalScreenshot mScreenshot;

private Handler mHandler = new Handler() {
 
 @Override
 public void handleMessage(Message msg) {
 
 switch (msg.what) {
 
 case 1:
 final Messenger callback = msg.replyTo;
 if (mScreenshot == null) {
 
 mScreenshot = new GlobalScreenshot(TakeScreenshotService.this);
 }
 mScreenshot.takeScreenshot(new Runnable() {
 
 @Override public void run() {
 
 Message reply = Message.obtain(null, 1);
 try {
 
 callback.send(reply);
 } catch (RemoteException e) {
 
 }
 }
 }, msg.arg1 &gt; 0, msg.arg2 &gt; 0);
 }
 }
 };

@Override
 public IBinder onBind(Intent intent) {
 
 return new Messenger(mHandler).getBinder();
 }
}
</pre> 
 </div> </td> 
 </tr> 
 </tbody> 
</table>

在这个类中，我们主要看调用接口，用到了mScreenshot.takeScreenshot（）传递了三个参数，第一个是个runnable，第二和第三个是之前message传递的两个参数msg.arg1和msg.arg2。最后我们看看这个函数takeScreenshot()，位于文件GlobalScreenshot.java中（跟之前的函数重名但是文件路径不一样）：

// Take the screenshot
 mScreenBitmap = Surface.screenshot((int) dims[0], (int) dims[1]);
 if (mScreenBitmap == null) {
 
 notifyScreenshotError(mContext, mNotificationManager);
 finisher.run();
 return;
 }

if (requiresRotation) {
 
 // Rotate the screenshot to the current orientation
 Bitmap ss = Bitmap.createBitmap(mDisplayMetrics.widthPixels,
 mDisplayMetrics.heightPixels, Bitmap.Config.ARGB_8888);
 Canvas c = new Canvas(ss);
 c.translate(ss.getWidth() / 2, ss.getHeight() / 2);
 c.rotate(degrees);
 c.translate(-dims[0] / 2, -dims[1] / 2);
 c.drawBitmap(mScreenBitmap, 0, 0, null);
 c.setBitmap(null);
 mScreenBitmap = ss;
 }

// Optimizations
 mScreenBitmap.setHasAlpha(false);
 mScreenBitmap.prepareToDraw();

// Start the post-screenshot animation
 startAnimation(finisher, mDisplayMetrics.widthPixels, mDisplayMetrics.heightPixels,
 statusBarVisible, navBarVisible);
 }
</pre> 
 </div> </td> 
 </tr> 
 </tbody> 
</table>

这段代码的注释比较详细，其实看到这里，我们算是真正看到截屏的操作了，具体的工作包括对屏幕大小、旋转角度的获取，然后调用Surface类的screenshot方法截屏保存到bitmap中，之后把这部分位图填充到一个画布上，最后再启动一个延迟的拍照动画效果。如果再往下探究screenshot方法，发现已经是一个native方法了：

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 </div> </td> 
 <td style=""> 
 <div style=""> 
 <pre style=""> /**
 * Like {@link #screenshot(int, int, int, int)} but includes all
 * Surfaces in the screenshot.
 *
 * @hide
 */
 public static native Bitmap screenshot(int width, int height);
</pre> 
 </div> </td> 
 </tr> 
 </tbody> 
</table>

使用JNI技术调用底层的代码，如果再往下走，会发现映射这这个jni函数在文件android\_view\_Surface.cpp中，这个真的已经是底层c++语言了，统一调用的底层函数是：

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 <td style=""> 
 <div style=""> 
 <pre style="">static jobject doScreenshot(JNIEnv* env, jobject clazz, jint width, jint height,
 jint minLayer, jint maxLayer, bool allLayers)
{
 
 ScreenshotPixelRef* pixels = new ScreenshotPixelRef(NULL);
 if (pixels-&gt;update(width, height, minLayer, maxLayer, allLayers) != NO_ERROR) {
 
 delete pixels;
 return 0;
 }

uint32_t w = pixels-&gt;getWidth();
 uint32_t h = pixels-&gt;getHeight();
 uint32_t s = pixels-&gt;getStride();
 uint32_t f = pixels-&gt;getFormat();
 ssize_t bpr = s * android::bytesPerPixel(f);

SkBitmap* bitmap = new SkBitmap();
 bitmap-&gt;setConfig(convertPixelFormat(f), w, h, bpr);
 if (f == PIXEL_FORMAT_RGBX_8888) {
 
 bitmap-&gt;setIsOpaque(true);
 }

if (w &gt; 0 &amp;&amp; h &gt; 0) {
 
 bitmap-&gt;setPixelRef(pixels)-&gt;unref();
 bitmap-&gt;lockPixels();
 } else {
 
 // be safe with an empty bitmap.
 delete pixels;
 bitmap-&gt;setPixels(NULL);
 }

return GraphicsJNI::createBitmap(env, bitmap, false, NULL);
}
</pre> 
 </div> </td> 
 </tr> 
 </tbody> 
</table>

由于对C++不熟，我这里就不敢多言了。其实到这里，算是对手机android源码中通过组合键屏幕截图的整个流程有个大体了解了，一般我们在改动中熟悉按键的捕获原理，并且清楚调用的截屏函数接口即可，如果有兴趣的，可以继续探究更深的底层是如何实现的。

[Link 1]: http://blog.csdn.net/woshinia/article/details/11520403#
[1_Android SDK]: http://blog.csdn.net/woshinia/article/details/11520403#t0
[2 _Android ddmlib]: http://blog.csdn.net/woshinia/article/details/11520403#t1
[3 Android_Native Programming_framebuffer]: http://blog.csdn.net/woshinia/article/details/11520403#t2
[4 _TakeScreenShotService]: http://blog.csdn.net/woshinia/article/details/11520403#t3
[Android]: http://blog.csdn.net/woshinia/article/details/11520403#t4
[Android 1]: http://blog.csdn.net/woshinia/article/details/11520403#t5