How to Access Activity from ActivityScenarioRule

Question

I am using ActivityScenarioRule for Espresso UI Testing and I wanted to get access to the method getStringArray(), calling which requires the Activity . So, is there any way to retrieve the Activity by the ActivityScenarioRule , maybe something similar to getActivity in ActivityTestRule.

@Rule
    public ActivityScenarioRule activityScenarioRule = new ActivityScenarioRule<>(MainActivity.class);

I am not using ActivityTestRule, because it is deprecated!

Try this approach, which doesn't need to use `onActivity()`: https://stackoverflow.com/questions/34683956/how-to-get-a-view-from-within-espresso-to-pass-into-an-idlingresource#49496282 — Mr-IDE, Nov 19 '21 at 04:58

score 28 · Accepted Answer · answered May 22 '20 at 16:06

28

Since it appears you're using Java, here's how you'd do it:

@Rule
ActivityScenarioRule<MainActivity> activityScenarioRule = new ActivityScenarioRule<>(MainActivity.class);

@Test
public void test() {
    activityScenarioRule.getScenario().onActivity(activity -> {
        // use 'activity'.
    });
}

Please read the documentation for more info on these new ways of interacting with the activity under test.

answered May 22 '20 at 16:06

gosr

4,593
9
46
82

3

How do I upgrade from ActivityTestRule to ActivityScenarioRule without rewriting every test case to fit this pattern? – Phlip Sep 04 '20 at 01:10
1

@Phlip See my answer below – Julian C Oct 09 '20 at 17:17

score 6 · Answer 2 · edited Jun 06 '22 at 05:34

For anyone who wants Activity, but that without need to re-write all tests to run on UI-thread, a fairly straightforward Java way to get it:

Waiting for UI

Assume you want to test if a dialog is shown after some delay, the onActivity(...) hook runs on UI-thread, which means waiting in there would cause the dialog to be nerver shown.

In such cases you need to keep a strong-reference to ActivityScenario (as that prevents Activity close).
Test should wait for onActivity(...) hook to be called, then keep passed Activity's reference.
Finally, move test logic out of onActivity(...) hook.

Example

private ActivityScenario mActivityScenario;

@After
public void tearDown() throws Exception {
  if (mActivityScenario != null) {
    mActivityScenario.close();
  }
  mActivityScenario = null;
}

@Override
public Activity getActivity() {
  if (mActivityScenario == null) {
    mActivityScenario = ActivityScenario.launch(getActivityClassForScenario());
  }
  return tryAcquireScenarioActivity(mActivityScenario);
}

protected static Activity tryAcquireScenarioActivity(ActivityScenario activityScenario) {
  Semaphore activityResource = new Semaphore(0);
  Activity[] scenarioActivity = new Activity[1];
  activityScenario.onActivity(activity -> {
    scenarioActivity[0] = activity;
    activityResource.release();
  });
  try {
    activityResource.tryAcquire(15000, TimeUnit.MILLISECONDS);
  } catch (InterruptedException e) {
    Assert.fail("Failed to acquire activity scenario semaphore");
  }
  Assert.assertNotNull("Scenario Activity should be non-null", scenarioActivity[0]);
  return scenarioActivity[0];
}

tim.k · Answer 3 · 2021-02-12T10:54:21.807

Espresso states the following:

At the same time, the framework prevents direct access to activities and views of the application because holding on to these objects and operating on them off the UI thread is a major source of test flakiness.

When there is no other way I use the following method to get an arbitrary activity from an ActivityScenarioRule. It uses onActivity mentioned in the accepted answer:

private <T extends Activity> T getActivity(ActivityScenarioRule<T> activityScenarioRule) {
        AtomicReference<T> activityRef = new AtomicReference<>();
        activityScenarioRule.getScenario().onActivity(activityRef::set);
        return activityRef.get();
    }

Any onView(...) code inside onActivity led to a timeout in my testcases. So, I extracted the activity and used it with success outside the onActivity. Beware tho! See the statement above.

The activity has to be packaged inside something to avoid the effectively final error in Java. — tim.k, Feb 12 '21 at 10:50
This Kotlin function worked for me private fun getActivity(): Activity { val activityRef: AtomicReference = AtomicReference() rule.scenario.onActivity { activityRef.set(it) } return activityRef.get() } — Kenneth Murerwa, Jan 04 '23 at 10:26

score 0 · Answer 4 · answered Nov 15 '21 at 08:10

0

@Test
    fun checkForUpdate() {
        val scenario = ActivityScenario.launch(MainActivity::class.java)
        scenario.onActivity {
            UpdateTool.checkForUpdate(it)
        }
    }

answered Nov 15 '21 at 08:10

shuidi

81
1
2

1

While this code may answer the question, providing additional context regarding how and/or why it solves the problem would improve the answer's long-term value. – Donald Duck Nov 15 '21 at 19:20

How to Access Activity from ActivityScenarioRule

4 Answers4

Waiting for UI

Example

Linked