MonkenRunner通过HierarchyViewer定位控件的方法和建议(Appium/UIAutomator/Robotium姊妹篇)

浏览数：30 / 时间：2015年06月11日

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：

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;
    }
}