uiautormator 总是 IllegalStateException:accessibilityservice 已经注册

Question

我在junitTest中使用uiautomator，在“@BeforeClass”我初始化一个UiDevice：“”mUIDevice = UiDevice.getInstance(InstrumentationRegistry.getInstrumentation()); 首先我完成了一个测试，然后我再次开始测试，我得到一个错误：java.lang.IllegalStateException：UiAutomationService android.accessibilityservice.IAccessibilityServiceClient$Stub$Proxy@7478d40alreadyregistered！

@RunWith(AndroidJUnit4.class)
public class DailyInstrumentedTest  {
@BeforeClass
public static void beforeTest(){


    try {
        mUIDevice = UiDevice.getInstance(InstrumentationRegistry.getInstrumentation());  //??device??
    }
}
@Test
public void test(){}
}