ChangeTextBehaviorTest fails

Hello,
I am running ChangeTextBehaviorTest on an emulator and a real device, but it fails with:

> java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.test.uiautomator.UiObject2.setText(java.lang.String)' on a null object reference
> at com.example.android.testing.uiautomator.BasicSample.ChangeTextBehaviorTest.testChangeText_newActivity(ChangeTextBehaviorTest.java:104)
> 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 org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
> 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$2.evaluate(ParentRunner.java:268)
> at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
> at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
> at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
> at android.support.test.internal.runner.TestExecutor.execute(TestExecutor.java:54)
> at android.support.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:240)
> at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1879)

Please advise,
Igor

从 ChangeTextBehaviorTest.java 开始，尤其是第 104 行，并在模拟器或设备上运行 ChangeTextBehaviorTest，以重现 UiObject2 为 null 的失败。跟踪哪个 UI 对象查找返回 null，并确认测试能够在不发生 NullPointerException 的情况下完成并验证文本更改。

由索引模型根据 Issue 内容生成。