嗨，所以我有这个应用程序，里面有这个RecipeActivity和一个recyclerview。
当您单击列表项时，它会打开另一个活动，并在意图中传递一个额外的内容。
我只是想用Espresso测试该简单功能（我从它开始）。这是我的代码：
@RunWith(AndroidJUnit4.class)
public class ShowIngredientsTest {
@Rule
public IntentsTestRule<RecipeActivity> testRule =
new IntentsTestRule<>(RecipeActivity.class);
@Test
public void checkIfIntentWorks() {
onView(withId(R.id.recipes_recyclerview))
.perform(RecyclerViewActions.actionOnItemAtPosition(0, click()));
intended(hasExtraWithKey(RECIPE_PARCEL));
}
}
现在，奇怪的是，当我在Nexus 5.0（Android 7.0）模拟器上运行它时，它通过了（我已经尝试过两次以确保）。
当我在Oneplus 3（带有Android 7.1.1）上（甚至在具有与Nexus 5.0相同的api级的其他模拟器中）尝试时，它就没有。
这是错误消息：
android.support.test.espresso.PerformException: Error performing 'android.support.test.espresso.contrib.RecyclerViewActions$ActionOnItemAtPositionViewAction@3d98130' on view 'with id: com.onval.bakingapp:id/recipes_recyclerview'.
at android.support.test.espresso.PerformException$Builder.build(PerformException.java:83)
at android.support.test.espresso.base.DefaultFailureHandler.getUserFriendlyError(DefaultFailureHandler.java:80)
at android.support.test.espresso.base.DefaultFailureHandler.handle(DefaultFailureHandler.java:56)
at android.support.test.espresso.ViewInteraction.runSynchronouslyOnUiThread(ViewInteraction.java:184)
at android.support.test.espresso.ViewInteraction.doPerform(ViewInteraction.java:115)
at android.support.test.espresso.ViewInteraction.perform(ViewInteraction.java:87)
at com.onval.bakingapp.ShowIngredientsTest.checkIfIngredientsAreShows(ShowIngredientsTest.java:34)
at java.lang.reflect.Method.invoke(Native Method)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at android.support.test.internal.statement.UiThreadStatement.evaluate(UiThreadStatement.java:55)
at android.support.test.rule.ActivityTestRule$ActivityStatement.evaluate(ActivityTestRule.java:270)
at org.junit.rules.RunRules.evaluate(RunRules.java:20)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runners.Suite.runChild(Suite.java:128)
at org.junit.runners.Suite.runChild(Suite.java:27)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
at android.support.test.internal.runner.TestExecutor.execute(TestExecutor.java:59)
at android.support.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:262)
at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:2110)
Caused by: java.lang.IllegalStateException: No view holder at position: 0
at android.support.test.espresso.contrib.RecyclerViewActions$ActionOnItemAtPositionViewAction.perform(RecyclerViewActions.java:290)
at android.support.test.espresso.ViewInteraction$1.run(ViewInteraction.java:144)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:428)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6321)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Tests ran to completion.
会是什么呢？当仿真器可以执行时，为什么不能在位置0执行操作？为什么它说在明确的位置上不存在该视图持有者？模拟器没有这个问题！
我唯一的想法是物理设备更快，并且它会在创建Viewholder之前进行检查...我试图添加一个
.perform(RecyclerViewActions.scrollToPosition(0))
在onView和actionOnItemAtPosition之间，但仍然无法正常工作。
我想念什么？先感谢您！
最佳答案
好的，我解决了，我需要使用IdlingResources。
关于java - 物理设备上的Android Espresso测试失败(PerformException)，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/46959184/