Android GrantPermissionRule未解析引用

我正在使用Android Studio与kotlin创建一个应用程序。我正在尝试对我的MainActivity类进行单元测试，因为我使用的是API 28，所以我需要授予权限才能运行单元测试。我将@get:Rule var permissionRule=GrantPermissionRule.grant（android.Manifest.permission.RECORD_AUDIO）放在测试类的顶部，但android Studio告诉我GrantPermissionRule是一个未解析的引用。我的代码如下

主要活动类别：

class MainActivity : AppCompatActivity(), MediaPlayer.OnCompletionListener {

    lateinit var recorder: MediaRecorder
    lateinit var player: MediaPlayer
    lateinit var file: File
    lateinit var button1: Button
    lateinit var button2: Button
    lateinit var button3: Button
    lateinit var tv1: TextView
    // coding180.com

    override fun onCreate(savedInstanceState: Bundle?) {

        // call the super class onCreate to complete the creation of activity 
        // like the view hierarchy
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            getPermissionToRecordAudio()
        }

        tv1 = findViewById(R.id.tv1) as TextView
        button1 = findViewById(R.id.btnStart) as Button
        button2 = findViewById(R.id.btnStop) as Button
        button3 = findViewById(R.id.btnPlay) as Button

        ...

    }

测试等级：

@RunWith(RobolectricTestRunner::class)
class MainActivityTest {

    @get:Rule var permissionRule = 
             GrantPermissionRule.grant(android.Manifest.permission.RECORD_AUDIO)

    lateinit var testMainActivity: MainActivity

    @Before
    fun setup() {
        testMainActivity = MainActivity()
    }

    @Test
    @Throws(Exception::class)
    fun onCreateTest() {

        //Activity variables
        val intent = Intent()
        val bundle = Bundle()
        intent.putExtras(bundle)
        val controller = Robolectric.buildActivity(MainActivity::class.java, 
                                                   intent).create()
        val activity = controller.get() as Activity

        //Start activity
        controller.start()

        //Asserts
        assertFalse(activity.isFinishing)
    }

---

我找不到其他有这个问题的人。有人知道为什么Android Studio不识别GrantPermissionRule以及如何修复它吗？

您的代码看起来不错，添加

androidTestImplementation 'com.android.support.test:rules:1.0.2'

---

到您的

build.gradle

是的，我的build.gradle中有这个，但它仍然无法识别GrantPermissionRule。@HeatherMinke您是否能够导入文件顶部的

import android.support.test.rule.GrantPermissionRule

？