Robotium源码解读-native控件/webview元素的获取和操作
目前比较有名的Uitest框架有Uiautomator/Robotium/Appium，由于一直对webview元素的获取和操作比较好奇，另外Robotium代码量也不是很大，因此打算学习一下。
一.环境准备以及初始化
用来说明的用例采用的是Robotium官网的一个tutorial用例-Notepad
@RunWith(AndroidJUnit4.class) public class NotePadTest { private static final String NOTE_1 = "Note 1"; private static final String NOTE_2 = "Note 2"; @Rule public ActivityTestRule<NotesList> activityTestRule = new ActivityTestRule<>(NotesList.class); private Solo solo; @Before public void setUp() throws Exception { //setUp() is run before a test case is started. //This is where the solo object is created. solo = new Solo(InstrumentationRegistry.getInstrumentation(), activityTestRule.getActivity()); } @After public void tearDown() throws Exception { //tearDown() is run after a test case has finished. //finishOpenedActivities() will finish all the activities that have been opened during the test execution. solo.finishOpenedActivities(); } @Test public void testAddNote() throws Exception { //Unlock the lock screen solo.unlockScreen(); //Click on action menu item add solo.clickOnView(solo.getView(R.id.menu_add)); //Assert that NoteEditor activity is opened solo.assertCurrentActivity("Expected NoteEditor Activity", NoteEditor.class); //In text field 0, enter Note 1 solo.enterText(0, NOTE_1); //Click on action menu item Save solo.clickOnView(solo.getView(R.id.menu_save)); //Click on action menu item Add solo.clickOnView(solo.getView(R.id.menu_add)); //In text field 0, type Note 2 solo.typeText(0, NOTE_2); //Click on action menu item Save solo.clickOnView(solo.getView(R.id.menu_save)); //Takes a screenshot and saves it in "/sdcard/Robotium-Screenshots/". solo.takeScreenshot(); //Search for Note 1 and Note 2 boolean notesFound = solo.searchText(NOTE_1) && solo.searchText(NOTE_2); //To clean up after the test case deleteNotes(); //Assert that Note 1 & Note 2 are found assertTrue("Note 1 and/or Note 2 are not found", notesFound); } }
在进行初始化时，Solo对象依赖Instrumentation对象以及被测应用的Activity对象，在这里是NotesList，然后所有的UI操作都依赖这个Solo对象。
二.Native控件解析与操作
1.Native控件解析
看一个标准的操作：solo.clickOnView(solo.getView(R.id.menu_save));
solo点击id为menu_save的控件，其中clickOnView传入参数肯定为menu_save的view对象，那这个是怎么获取的呢？
由于调用比较深，因此直接展示关键方法
public View waitForView(int id, int index, int timeout, boolean scroll) { HashSet uniqueViewsMatchingId = new HashSet(); long endTime = SystemClock.uptimeMillis() + (long)timeout; while(SystemClock.uptimeMillis() <= endTime) { this.sleeper.sleep(); Iterator i$ = this.viewFetcher.getAllViews(false).iterator(); while(i$.hasNext()) { View view = (View)i$.next(); Integer idOfView = Integer.valueOf(view.getId()); if(idOfView.equals(Integer.valueOf(id))) { uniqueViewsMatchingId.add(view); if(uniqueViewsMatchingId.size() > index) { return view; } } } if(scroll) { this.scroller.scrollDown(); } } return null; }
这个方法是先去获取所有的View： this.viewFetcher.getAllViews(false)，然后通过匹配id来获取正确的View。
那Robotium是怎么获取到所有的View呢？这就要看看viewFetcher里的实现了。
public ArrayList<View> getAllViews(boolean onlySufficientlyVisible) { View[] views = this.getWindowDecorViews(); ArrayList allViews = new ArrayList(); View[] nonDecorViews = this.getNonDecorViews(views); View view = null; if(nonDecorViews != null) { for(int ignored = 0; ignored < nonDecorViews.length; ++ignored) { view = nonDecorViews[ignored]; try { this.addChildren(allViews, (ViewGroup)view, onlySufficientlyVisible); } catch (Exception var9) { ; } if(view != null) { allViews.add(view); } } } if(views != null && views.length > 0) { view = this.getRecentDecorView(views); try { this.addChildren(allViews, (ViewGroup)view, onlySufficientlyVisible); } catch (Exception var8) { ; } if(view != null) { allViews.add(view); } } return allViews; }
需要说明的是，DecorView是整个ViewTree的最顶层View，它是一个FrameLayout布局，代表了整个应用的界面。
从上面的代码可以看到，allViews包括WindowDecorViews，nonDecorViews，RecentDecorView。所以，我对这三个封装比较感兴趣，他们是怎么拿到WindowDecorViews，nonDecorViews，RecentDecorView的呢？
继续看代码，可以看到以下方法（看注释）
// 获取 DecorViews public View[] getWindowDecorViews() { try { Field viewsField = windowManager.getDeclaredField("mViews"); Field instanceField = windowManager.getDeclaredField(this.windowManagerString); viewsField.setAccessible(true); instanceField.setAccessible(true); Object e = instanceField.get((Object)null); View[] result; if(VERSION.SDK_INT >= 19) { result = (View[])((ArrayList)viewsField.get(e)).toArray(new View[0]); } else { result = (View[])((View[])viewsField.get(e)); } return result; } catch (Exception var5) { var5.printStackTrace(); return null; } } // 获取NonDecorViews private final View[] getNonDecorViews(View[] views) { View[] decorViews = null; if(views != null) { decorViews = new View[views.length]; int i = 0; for(int j = 0; j < views.length; ++j) { View view = views[j]; if(!this.isDecorView(view)) { decorViews[i] = view; ++i; } } } return decorViews; } // 获取RecentDecorView public final View getRecentDecorView(View[] views) { if(views == null) { return null; } else { View[] decorViews = new View[views.length]; int i = 0; for(int j = 0; j < views.length; ++j) { View view = views[j]; if(this.isDecorView(view)) { decorViews[i] = view; ++i; } } return this.getRecentContainer(decorViews); } }
其中DecorViews就不用多说了，通过反射拿到一个里面的元素都是View的List，而NonDecorViews则是通过便利DectorViews进行过滤，nameOfClass 不满足要求的，则为NonDecorViews
String nameOfClass = view.getClass().getName(); return nameOfClass.equals("com.android.internal.policy.impl.PhoneWindow$DecorView") || nameOfClass.equals("com.android.internal.policy.impl.MultiPhoneWindow$MultiPhoneDecorView") || nameOfClass.equals("com.android.internal.policy.PhoneWindow$DecorView");
而recentlyView则通过以下条件进行判断，满足则为recentlyView
view != null && view.isShown() && view.hasWindowFocus() && view.getDrawingTime() > drawingTime
2.Native控件解析
依旧说的是这个操作：solo.clickOnView(solo.getView(R.id.menu_save));接下来要看的是clickOnView的封装了。
这部分实现相对简单很多了，获取控件坐标的中央X,Y值后，利用instrumentation的sendPointerSync来完成点击/长按操作
public void clickOnScreen(float x, float y, View view) { boolean successfull = false; int retry = 0; SecurityException ex = null; while(!successfull && retry < 20) { long downTime = SystemClock.uptimeMillis(); long eventTime = SystemClock.uptimeMillis(); MotionEvent event = MotionEvent.obtain(downTime, eventTime, 0, x, y, 0); MotionEvent event2 = MotionEvent.obtain(downTime, eventTime, 1, x, y, 0); try { this.inst.sendPointerSync(event); this.inst.sendPointerSync(event2); successfull = true; } catch (SecurityException var16) { ex = var16; this.dialogUtils.hideSoftKeyboard((EditText)null, false, true); this.sleeper.sleep(300); ++retry; View identicalView = this.viewFetcher.getIdenticalView(view); if(identicalView != null) { float[] xyToClick = this.getClickCoordinates(identicalView); x = xyToClick[0]; y = xyToClick[1]; } } } if(!successfull) { Assert.fail("Click at (" + x + ", " + y + ") can not be completed! (" + (ex != null?ex.getClass().getName() + ": " + ex.getMessage():"null") + ")"); } }
3.总结：
从源码中可以看出，其实native控件操作的思想是这样的。
通过android.view.windowManager获取到所有的view，然后经过过滤得到自己需要的view，最后通过计算view的 Coordinates得到中央坐标，最后依赖instrument来完成操作。
三.Webview的解析与操作
webview的解析需要利用JS注入获取到Web页面的元素，进行过滤后再进行操作。
webview的调试环境可以利用inspect来进行，具体参考此文章：http://www.cnblogs.com/sunshq/p/4111610.html
在这里进行说明的解析操作代码为：
ArrayList<WebElement> webElements = solo.getCurrentWebElements(By.className("ns-video ns-icon"));
solo.clickOnWebElement(webElements.get(0));
这段代码很好理解，取出className为"btn btn-block primary"的元素，并点击第一个。在这里，元素的可操作对象为WebElement.
debug界面为：
在具体debug代码前，我们有必要先了解一下解析Webview的流程应该是怎样的（尽管我是看代码了解的，但先把流程说一下方便解说），不然很可能会云里雾里。流程如下：
1. 获取所有的view，过滤出webview
2.初始化javascript环境
3.加载本地js并注入
4.WebElment操作
接下来，自然而然，带着目的去看代码，就可以很清楚每一步在做什么了。
1. 获取所有的view，过滤出webview
（1）直接跳到关键代码，首先要看的是By是用来干嘛的。通过查看源码，可以发现，其实By是一个Java bean，里面封装了Id/CssSelector/ClassName/Text等等属性，可以理解为WebView中的目标对象封装。
public boolean executeJavaScript(By by, boolean shouldClick) { return by instanceof Id?this.executeJavaScriptFunction("id(\"" + by.getValue() + "\", \"" + shouldClick + "\");"):(by instanceof Xpath?this.executeJavaScriptFunction("xpath(\"" + by.getValue() + "\", \"" + shouldClick + "\");"):(by instanceof CssSelector?this.executeJavaScriptFunction("cssSelector(\"" + by.getValue() + "\", \"" + shouldClick + "\");"):(by instanceof Name?this.executeJavaScriptFunction("name(\"" + by.getValue() + "\", \"" + shouldClick + "\");"):(by instanceof ClassName?this.executeJavaScriptFunction("className(\"" + by.getValue() + "\", \"" + shouldClick + "\");"):(by instanceof Text?this.executeJavaScriptFunction("textContent(\"" + by.getValue() + "\", \"" + shouldClick + "\");"):(by instanceof TagName?this.executeJavaScriptFunction("tagName(\"" + by.getValue() + "\", \"" + shouldClick + "\");"):false)))))); } private boolean executeJavaScriptFunction(final String function) { ArrayList webViews = this.viewFetcher.getCurrentViews(WebView.class, true); final WebView webView = (WebView)this.viewFetcher.getFreshestView((ArrayList)webViews); if(webView == null) { return false; } else { final String javaScript = this.setWebFrame(this.prepareForStartOfJavascriptExecution(webViews)); this.inst.runOnMainSync(new Runnable() { public void run() { if(webView != null) { webView.loadUrl("javascript:" + javaScript + function); } } }); return true; } }
executeJavaScript获取到的是对应的执行方法调用语句，这个根据自己定位的元素决定，在这，我的为："className(\"ns-video ns-icon\", \"false\");"
（2）getCurrentViews，获取所有当前View
public <T extends View> ArrayList<T> getCurrentViews(Class<T> classToFilterBy, boolean includeSubclasses, View parent) { ArrayList filteredViews = new ArrayList(); ArrayList allViews = this.getViews(parent, true); Iterator i$ = allViews.iterator(); while(true) { View view; Class classOfView; do { do { if(!i$.hasNext()) { allViews = null; return filteredViews; } view = (View)i$.next(); } while(view == null); classOfView = view.getClass(); } while((!includeSubclasses || !classToFilterBy.isAssignableFrom(classOfView)) && (includeSubclasses || classToFilterBy != classOfView)); filteredViews.add(classToFilterBy.cast(view)); } }
其中classToFilterBy为android.webkit.Webview这个类，所作的操作为调用获取所有View（跟navitive调用的方法一致），包括控件view跟webView，如图所示
然后逐一过滤出，条件为(!includeSubclasses || !classToFilterBy.isAssignableFrom(classOfView)) && (includeSubclasses || classToFilterBy != classOfView))。在这里加个题外话，因为robotium默认的是android.webkit.Webview，因此如果你用robotium去解析操作第三方内核的Webview，是会失败的，解决办法就是改源码？
2.初始化javascript环境
看（1）的代码：this.setWebFrame(this.prepareForStartOfJavascriptExecution(webViews));
在这里会初始化一个robotiumWebCLient, 并将webChromeClient设置成RobotiumWebClient.this.robotiumWebClient，由于我对这一块也不熟悉，不太清楚这一块的目的，因此不赘述，姑且认为是执行js注入的环境初始化。
3.加载js脚本并注入
private String getJavaScriptAsString() { InputStream fis = this.getClass().getResourceAsStream("RobotiumWeb.js"); StringBuffer javaScript = new StringBuffer(); try { BufferedReader e = new BufferedReader(new InputStreamReader(fis)); String line = null; while((line = e.readLine()) != null) { javaScript.append(line); javaScript.append("\n"); } e.close(); return javaScript.toString(); } catch (IOException var5) { throw new RuntimeException(var5); } }
这一块就没多少要说的了，就是把本地的js脚本加载进来，方便执行，最后在异步线程中将js注入，参考（1）中的webView.loadUrl("javascript:" + javaScript + function);
在这里可以展示一下我这边注入的js是怎样的(只展示结构，具体方法内容略掉)：
javascript:/** * Used by the web methods. * * @author Renas Reda, renas.reda@robotium.com * */ function allWebElements() { ... } function allTexts() { ... } function clickElement(element){ var e = document.createEvent('MouseEvents'); e.initMouseEvent('click', true, true, window, 1, 0, 0, 0, 0, false, false, false, false, 0, null); element.dispatchEvent(e); } function id(id, click) { ... } function xpath(xpath, click) { ... } function cssSelector(cssSelector, click) { ... } function name(name, click) { ... } function className(nameOfClass, click) { ... } function textContent(text, click) { ... } function tagName(tagName, click) { ... } function enterTextById(id, text) { ... } function enterTextByXpath(xpath, text) { ... } function enterTextByCssSelector(cssSelector, text) { ... } function enterTextByName(name, text) { ... } function enterTextByClassName(name, text) { ... } function enterTextByTextContent(textContent, text) { ... } function enterTextByTagName(tagName, text) { ... } function promptElement(element) { ... } function promptText(element, range) { ... } function finished(){ prompt('robotium-finished'); } className("ns-video ns-icon", "false");
4.WebElment操作
接下来便是元素操作了，在这里的操作对象是WebElment，获取到下X，Y坐标进行对应操作就可以了。
总结：
这篇文章展示了robotium是如何去识别控件跟webview元素的，这个基本上是一个框架能用与否的关键，有兴趣造轮子或者想学习robotium源码的可以多多参考。
