UIAutomator2.0详解（UIDevice篇----performActionAndWait）

方法含义：执行action后，判断timeout时间内，是否出现Event。

方法返回值：布尔型，若有Event发生，则返回true，否则返回false。

EventCondition是一个抽象类，可用通过 android.support.test.uiautomator.Until中提供的两个静态方法，来获取实体对象。

public static EventCondition<Boolean> newWindow() public static EventCondition<Boolean> scrollFinished(final Direction direction) 

查看源码，可发现newWindow()是指发生window状态变化，或内容变化所引发的Event。

而scrollFinished，则是当当滑动到某一方向尽头时所引发的Event。

还是用一个示例来看一下效果。先用newWindow为EventCondition.

核心代码如下：

public class WaitConditionTest extends UIDeviceTest {    @Test    public void test1(){        String packageName="com.breakloop.salaryshow";        String activityName=".MainActivity";        boolean result1=mDevice.performActionAndWait(new Runnable() {            @Override            public void run() {                Log.i(TAG, "run: new window appeared in 5 s");            }        }, Until.newWindow(), 5000);        Log.i(TAG, "test1: result = "+result1);        Utils.startAPP(mDevice,packageName,activityName);        mDevice.waitForWindowUpdate(packageName,5000);        Utils.closeAPP(mDevice,packageName);    }}

执行效果如下：

执行结果如下：

11-21 23:50:29.221 I/TestRunner: run started: 1 tests11-21 23:50:29.236 I/TestRunner: started: test1(com.breakloop.u2demo.uidevice.WaitConditionTest)11-21 23:50:29.238 I/MonitoringInstrumentation: Activities that are still in CREATED to STOPPED: 011-21 23:50:29.239 I/com.breakloop.u2demo.uidevice.WaitConditionTest: run: new window appeared in 5 s11-21 23:50:34.684 I/com.breakloop.u2demo.uidevice.WaitConditionTest: test1: result = false11-21 23:50:34.705 I/TestRunner: finished: test1(com.breakloop.u2demo.uidevice.WaitConditionTest)

由执行结果可见，在5秒后，输出了“result = false”，说明5秒内未有新窗口事件产生。原因在于，打开APP这个操作，发生在5秒之后。

我们修改代码，将

Utils.startAPP(mDevice,packageName,activityName);

放置在performActionAndWait之前，查看执行结果。

11-22 00:28:43.961 I/TestRunner: started: test1(com.breakloop.u2demo.uidevice.WaitConditionTest)11-22 00:28:43.963 I/MonitoringInstrumentation: Activities that are still in CREATED to STOPPED: 011-22 00:28:44.322 I/com.breakloop.u2demo.uidevice.WaitConditionTest: run: new window appeared in 5 s11-22 00:28:44.411 I/com.breakloop.u2demo.uidevice.WaitConditionTest: test1: result = true11-22 00:28:50.912 I/TestRunner: finished: test1(com.breakloop.u2demo.uidevice.WaitConditionTest)

可以发现，“result = true”，说明有newWindow事件发生。并且，“result = true”紧接着“new window appeared in 5 s”输出，说明并没有等待发生。这与scrollFinished不同。

下面，我们再以scrollFinished为触发条件，看一下效果。
我们在第二个fragment中，添加一个下拉动作。

实例代码如下：

@Test    public void test2(){        String packageName="com.breakloop.salaryshow";        String activityName=".MainActivity";        Utils.startAPP(mDevice,packageName,activityName);        mDevice.waitForWindowUpdate(packageName,2000);        int h=mDevice.getDisplayHeight();        int w=mDevice.getDisplayWidth();        int left=200;        int right=w-200;        int up=200;        int down=h-200;        int step=10;        mDevice.swipe(right, h/2, left, h/2, step);        mDevice.waitForWindowUpdate(packageName,1000);        mDevice.swipe(w/2, down,  w/2, up, step);        boolean result1=mDevice.performActionAndWait(new Runnable() {            @Override            public void run() {                Log.i(TAG, "run: scroll Down");            }        },Until.scrollFinished(Direction.DOWN),2000);        Log.i(TAG, "test1: result = "+result1);        mDevice.waitForWindowUpdate(packageName,1000);        Utils.closeAPP(mDevice,packageName);    }

效果图如下：

结果如下：

10:34:55.344 I/TestRunner: started: test2(com.breakloop.u2demo.uidevice.WaitConditionTest)10:34:55.351 I/MonitoringInstrumentation: Activities that are still in CREATED to STOPPED: 010:35:01.800 I/com.breakloop.u2demo.uidevice.WaitConditionTest: run: scroll Down10:35:06.801 I/com.breakloop.u2demo.uidevice.WaitConditionTest: test1: result = true10:35:08.408 I/TestRunner: finished: test2(com.breakloop.u2demo.uidevice.WaitConditionTest)

由结果可见，在action完成后，scroll down事件发生了，但仍等待了timeout（5秒）的时间。这一点与newWindow事件不同。

结论：

对于performActionAndWait方法，不同的事件，效果也不同。若newWindow事件若发生，程序将不再等待，继续执行后续动作。而若scroll事件发生，程序将等待timeout，然后在继续后续动作。

测试机型为华为Mate8。不知其它机型是否有同样的效果。童鞋可尝试，望分享。