1. 背景
在使用MonkeyRunner的时候我们经常会用到Chimchat下面的HierarchyViewer模块来获取目标控件的一些信息来辅助我们测试，但在MonkeyRunner的官网上是没有看到相应的API的描述的,上面只有以下三个类的API引用信息(http://developer.android.com/tools/help/MonkeyDevice.html)
- MonkeyDevice
- MonkeyImage
- MonkeyRunner
所以在这里尝试整理下HierarchyViewer提供的API的用法并根据实践作出相应的建议，首先请看该类提供的所有可用的公共方法，内容并不多：
从图中可以看出HierarchyViewer类中提供的方法主要是用来定位控件相关的，包括根据ID取得控件，根据控件取得控件在屏幕的位置等。但还有一些其他方法，我们会顺带一并描述，毕竟内容并不多。
本文我们依然跟上几篇文章一样以SDK自带的NotePad为实验目标，看怎么定位到NotesList下面的Menu Options中的Add note这个Menu Entry。
以下是通过HierarchyViewer这个工具获得的目标设备界面的截图：
2.findViewById(String id)
2.1 示例
targetDevice = MonkeyRunner.waitForConnection()
'''
public ViewNode findViewById(String id)
* @param id id for the view.
* @return view with the specified ID, or {@code null} if no view found.
'''
viewer = targetDevice.getHierarchyViewer()
button = viewer.findViewById('id/title')
text = viewer.getText(button)
print text.encode('utf-8')
2.2 分析和建议
此API的目的就是通过控件的ID来获得代表用户控件的一个ViewNode对象。因为这个是第一个示例，所以这里有几点需要说明
- 一旦MonkeyRunner连接上设备，会立刻获得一个MonkeyDevice的对象代表了目标测试设备，我们就是通过这个设备对象来控制设备的
- 注意这里需要填写的id的格式和UIAutomatorViewer获得ResourceId是不一样的，请看下图UIAutomatorViewer截图中ResourceId前面多出了"android:"字串：
- 这个方法返回的一个ViewNode的对象，代表目标控件，拥有大量控件相关的属性，由于篇幅问题这里不详述，往后应该会另外撰文描述它的使用。在本文里知道它代表了目标控件就行了
- 最后打印的时候需要转换成UTF-8编码的原因跟Jython默认的编码格式有关系，具体描述和Workaround请查看：http://www.haogongju.net/art/1636997
3. findViewById(String id, ViewNode rootNode)
3.1示例
'''
public ViewNode findViewById(String id, ViewNode rootNode)
* Find a view by ID, starting from the given root node
* @param id ID of the view you're looking for
* @param rootNode the ViewNode at which to begin the traversal
* @return view with the specified ID, or {@code null} if no view found.
'''
iconMenuView = viewer.findViewById('id/icon_menu')
button = viewer.findViewById('id/title',iconMenuView)
print "Button Text:",text.encode('utf-8')
3.2分析
这个方法是上面方法的一个重载，除了需要指定ID之外，还需要指定一个rootNode，该rootNode指的就是已知控件的父控件，父到什么层级就没有限制了。为什么需要这个方法了，我们可以想象下这种情况：同一界面上存在两个控件拥有相同的ID，但是他们某一个层级父控件开始发生分叉。那么我们就可以把rootNode指定为该父控件（不包括）到目标控件(不包含）路径中的其中一个父控件来精确定位我们需要的目标控件了。
如我们的示例就是明确指出我们需要的是在父控件“id/icon_menu"（请看背景的hierarchyviewer截图）下面的那个”id/title"控件。
4 getAbsolutePositionOfView(ViewNode node)
4.1示例
'''
public static Point getAbsoluteCenterOfView(ViewNode node)
* Gets the absolute x/y center of the specified view node.
*
* @param node view node to find position of.
* @return absolute x/y center of the specified view node.
*/
'''
point = viewer.getAbsoluteCenterOfView(button)
print "Button Absolute Center Position:",point
4.2 分析和建议
这个API的目的是想定位一个已知ViewNode控件的左上角在屏幕上的绝对坐标。对于我们正常的APP里面的控件，本人实践过是没有问题的。但是有一种情况要特别注意：这个对Menu Options下面的控件是无效的！
以上示例最后一段代码的输出是（3，18),其实这里不用想都知道这个不可能是相对屏幕左上角坐标（0，0）的绝对坐标值了，就偏移这一点点像素，你真的当我的实验机器HTC Incredible S是可以植入脑袋的神器啊。
那么这个数据是如何获得的呢？其实按照我的理解（真的只是我自己的理解，不对的话就指正吧，但请描述详细点以供我参考），这个函数的定义应该是“获得从最上层的DecorView（具体DectorView的描述请查看我以前CSDN转载的一篇文章《Android DecorView浅析》）左上角坐标到目标控件的的偏移坐标”，只是这个最上层的DecorView的坐标一般都是从（0，0）开始而已。如下图我认为最上面的那个FrameLayout就代表了DecorView，或者说整个窗体
那么在假设我的观点是对的情况下，这个就很好解析了，请看Menu Option的最上层FrameLayout的绝对坐标是（0，683）
而Add note的绝对坐标是（3，701）
两者一相减就是和我们的输出结果绝对吻合的（3，18）了。
5. getAbsoluteCenterOfView(ViewNode node)
5.1 示例
'''
public static Point getAbsoluteCenterOfView(ViewNode node)
* Gets the absolute x/y center of the specified view node.
*
* @param node view node to find position of.
* @return absolute x/y center of the specified view node.
*/
'''
point = viewer.getAbsoluteCenterOfView(button)
print "Button Absolute Center Position:",point
5.2 分析和建议
这个方法的目的是获得目标ViewNode控件的中间点的绝对坐标值，但是对Menu Options下面的控件同样不适用，具体请查看第3章节。
以下两个方法都不是用来定位控件的，一并记录下来以供参考。
6. getFocusedWindowName()
6.1 示例
'''
public String getFocusedWindowName()
* Gets the window that currently receives the focus.
*
* @return name of the window that currently receives the focus.
'''
window = viewer.getFocusedWindowName()
print "Window Name:",window.encode('utf-8')
6.2 解析
其实就是获得当前打开的窗口的packageName/activityName，输出与HierarchyViewer工具检测到的信息一致，所以猜想其用到同样的方法。 输出： 
HierarchyViewer监控信息：
HierarchyViewer监控信息：
7. visible(ViewNode node)
7.1 示例
'''
public boolean visible(ViewNode node)
* Gets the visibility of a given element.
* @param selector selector for the view.
* @return True if the element is visible.
'''
isVisible = viewer.visible(button)
print "is visible:",isVisible
就是查看下控件是否可见，没什么好解析的了。8. 测试代码
from com.android.monkeyrunner import MonkeyRunner,MonkeyDevice
from com.android.monkeyrunner.easy import EasyMonkeyDevice,By
from com.android.chimpchat.hierarchyviewer import HierarchyViewer
from com.android.hierarchyviewerlib.models import ViewNode, Window
from java.awt import Point
#from com.android.hierarchyviewerlib.device import
#Connect to the target targetDevice
targetDevice = MonkeyRunner.waitForConnection()
easy_device = EasyMonkeyDevice(targetDevice) #touch a button by id would need this
targetDevice.startActivity(component="com.example.android.notepad/com.example.android.notepad.NotesList")
#time.sleep(2000)
#invoke the menu options
MonkeyRunner.sleep(6)
targetDevice.press('KEYCODE_MENU', MonkeyDevice.DOWN_AND_UP);
'''
public ViewNode findViewById(String id)
* @param id id for the view.
* @return view with the specified ID, or {@code null} if no view found.
'''
viewer = targetDevice.getHierarchyViewer()
button = viewer.findViewById('id/title')
text = viewer.getText(button)
print text.encode('utf-8')
'''
public ViewNode findViewById(String id, ViewNode rootNode)
* Find a view by ID, starting from the given root node
* @param id ID of the view you're looking for
* @param rootNode the ViewNode at which to begin the traversal
* @return view with the specified ID, or {@code null} if no view found.
'''
iconMenuView = viewer.findViewById('id/icon_menu')
button = viewer.findViewById('id/title',iconMenuView)
print "Button Text:",text.encode('utf-8')
'''
public String getFocusedWindowName()
* Gets the window that currently receives the focus.
*
* @return name of the window that currently receives the focus.
'''
window = viewer.getFocusedWindowName()
print "Window Name:",window.encode('utf-8')
'''
public static Point getAbsoluteCenterOfView(ViewNode node)
* Gets the absolute x/y center of the specified view node.
*
* @param node view node to find position of.
* @return absolute x/y center of the specified view node.
*/
'''
point = viewer.getAbsoluteCenterOfView(button)
print "Button Absolute Center Position:",point
'''
public static Point getAbsolutePositionOfView(ViewNode node)
* Gets the absolute x/y position of the view node.
*
* @param node view node to find position of.
* @return point specifying the x/y position of the node.
'''
point = viewer.getAbsolutePositionOfView(button)
print "Button Absolute Position:", point
'''
public boolean visible(ViewNode node)
* Gets the visibility of a given element.
* @param selector selector for the view.
* @return True if the element is visible.
'''
isVisible = viewer.visible(button)
print "is visible:",isVisible
9.附上HierarchyViewer类的源码方便参照
/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.chimpchat.hierarchyviewer;
import com.android.ddmlib.IDevice;
import com.android.ddmlib.Log;
import com.android.hierarchyviewerlib.device.DeviceBridge;
import com.android.hierarchyviewerlib.device.ViewServerDevice;
import com.android.hierarchyviewerlib.models.ViewNode;
import com.android.hierarchyviewerlib.models.Window;
import org.eclipse.swt.graphics.Point;
/**
* Class for querying the view hierarchy of the device.
*/
public class HierarchyViewer {
public static final String TAG = "hierarchyviewer";
private IDevice mDevice;
/**
* Constructs the hierarchy viewer for the specified device.
*
* @param device The Android device to connect to.
*/
public HierarchyViewer(IDevice device) {
this.mDevice = device;
setupViewServer();
}
private void setupViewServer() {
DeviceBridge.setupDeviceForward(mDevice);
if (!DeviceBridge.isViewServerRunning(mDevice)) {
if (!DeviceBridge.startViewServer(mDevice)) {
// TODO: Get rid of this delay.
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
}
if (!DeviceBridge.startViewServer(mDevice)) {
Log.e(TAG, "Unable to debug device " + mDevice);
throw new RuntimeException("Could not connect to the view server");
}
return;
}
}
DeviceBridge.loadViewServerInfo(mDevice);
}
/**
* Find a view by id.
*
* @param id id for the view.
* @return view with the specified ID, or {@code null} if no view found.
*/
public ViewNode findViewById(String id) {
ViewNode rootNode = DeviceBridge.loadWindowData(
new Window(new ViewServerDevice(mDevice), "", 0xffffffff));
if (rootNode == null) {
throw new RuntimeException("Could not dump view");
}
return findViewById(id, rootNode);
}
/**
* Find a view by ID, starting from the given root node
* @param id ID of the view you're looking for
* @param rootNode the ViewNode at which to begin the traversal
* @return view with the specified ID, or {@code null} if no view found.
*/
public ViewNode findViewById(String id, ViewNode rootNode) {
if (rootNode.id.equals(id)) {
return rootNode;
}
for (ViewNode child : rootNode.children) {
ViewNode found = findViewById(id,child);
if (found != null) {
return found;
}
}
return null;
}
/**
* Gets the window that currently receives the focus.
*
* @return name of the window that currently receives the focus.
*/
public String getFocusedWindowName() {
int id = DeviceBridge.getFocusedWindow(mDevice);
Window[] windows = DeviceBridge.loadWindows(new ViewServerDevice(mDevice), mDevice);
for (Window w : windows) {
if (w.getHashCode() == id)
return w.getTitle();
}
return null;
}
/**
* Gets the absolute x/y position of the view node.
*
* @param node view node to find position of.
* @return point specifying the x/y position of the node.
*/
public static Point getAbsolutePositionOfView(ViewNode node) {
int x = node.left;
int y = node.top;
ViewNode p = node.parent;
while (p != null) {
x += p.left - p.scrollX;
y += p.top - p.scrollY;
p = p.parent;
}
return new Point(x, y);
}
/**
* Gets the absolute x/y center of the specified view node.
*
* @param node view node to find position of.
* @return absolute x/y center of the specified view node.
*/
public static Point getAbsoluteCenterOfView(ViewNode node) {
Point point = getAbsolutePositionOfView(node);
return new Point(
point.x + (node.width / 2), point.y + (node.height / 2));
}
/**
* Gets the visibility of a given element.
*
* @param selector selector for the view.
* @return True if the element is visible.
*/
public boolean visible(ViewNode node) {
boolean ret = (node != null)
&& node.namedProperties.containsKey("getVisibility()")
&& "VISIBLE".equalsIgnoreCase(
node.namedProperties.get("getVisibility()").value);
return ret;
}
/**
* Gets the text of a given element.
*
* @param selector selector for the view.
* @return the text of the given element.
*/
public String getText(ViewNode node) {
if (node == null) {
throw new RuntimeException("Node not found");
}
ViewNode.Property textProperty = node.namedProperties.get("text:mText");
if (textProperty == null) {
// give it another chance, ICS ViewServer returns mText
textProperty = node.namedProperties.get("mText");
if (textProperty == null) {
throw new RuntimeException("No text property on node");
}
}
return textProperty.value;
}
}
10. 参考阅读
以下是之前不同框架的控件定位的实践，一并列出来方便直接跳转参考：
| 作者 | 自主博客 | 微信服务号及扫描码 | CSDN |
| 天地会珠海分舵 | http://techgogogo.com | 服务号:TechGoGoGo扫描码:  |
http://blog.csdn.net/zhubaitian |