Android自动化测试初探（二）: Hierarchyviewer 捕获Element的实现原理

　　Android SDK tools下的工具hierarchyviewer可以展现Device上的Element的层次分布和自身属性，其核心函数之一就是LoadScene，研究后发现其实现方法是向Device的4939端口通过socket的方式发送了一个DUMP的命令，Device会自动处理该命令并将所有Screen上的Element层次结构和属性一并发回，实现代码如下：

public static void listElement(IDevice device){ Socket socket;       BufferedReader in;       BufferedWriter out;       socket = null;       in = null;       out = null;                  do{         DeviceBridge.setupDeviceForward(device);       }while(4939!=DeviceBridge.getDeviceLocalPort(device));                  socket = new Socket();       try { socket.connect(new InetSocketAddress("127.0.0.1", DeviceBridge.getDeviceLocalPort(device)));   out = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));   in = new BufferedReader(new InputStreamReader(socket.getInputStream()));            System.out.println("==> DUMP"); out.write((new StringBuilder()).append("DUMP -1").toString());            out.newLine();             out.flush();             do             {                   String line; if ((line = in.readLine()) == null || "DONE.".equalsIgnoreCase(line))                         break;                   line = line.trim();                   System.out.println(line);             } while (true);       } catch (IOException e) {                   e.printStackTrace();       } }

　　运行后的结果摘录其中一部分（button5），列举如下。注：当前device中运行的是2.1SDK中自带的Calculator程序：

com.android.calculator2.ColorButton@43b8bee8mText=1,5 getEllipsize()=4,null mMinWidth=1,0 mMinHeight=1,0 mMeasuredWidth=2,79 mPaddingBottom=1,0 mPaddingLeft=1,0 mPaddingRight=1,0 mPaddingTop=1,0 mMeasuredHeight=2,78 mLeft=2,81 mPrivateFlags_DRAWING_CACHE_INVALID=3,0x0 mPrivateFlags_DRAWN=4,0x20 mPrivateFlags=8,16779312 mID=9,id/digit5 mRight=3,160 mScrollX=1,0 mScrollY=1,0 mTop=1,0 mBottom=2,78 mUserPaddingBottom=1,0 mUserPaddingRight=1,0 mViewFlags=9,402669569 getBaseline()=2,54 getHeight()=2,78 layout_gravity=4,NONE layout_weight=3,1.0 layout_bottomMargin=1,0 layout_leftMargin=1,1 layout_rightMargin=1,0 layout_topMargin=1,0 layout_height=11,FILL_PARENT layout_width=11,FILL_PARENT getTag()=4,null getVisibility()=7,VISIBLE getWidth()=2,79 hasFocus()=5,false isClickable()=4,true isDrawingCacheEnabled()=5,false isEnabled()=4,true isFocusable()=4,true isFocusableInTouchMode()=5,false isFocused()=5,false isHapticFeedbackEnabled()=4,true isInTouchMode()=4,true isOpaque()=5,false isSelected()=5,false isSoundEffectsEnabled()=4,true willNotCacheDrawing()=5,false willNotDraw()=5,false

　　另外还支持如下命令：

- LIST will show the list of windows: LIST 43514758 com.android.launcher/com.android.launcher.Launcher 4359e4d0 TrackingView 435b00a0 StatusBarExpanded 43463710 StatusBar 43484c58 Keyguard DONE.