Question

I have a method that attempts to programatically scroll to a position in a ListView. The method has some conditionals so that its implementation differs slightly based on the Android SDK version the app is running on.

The functionality works fine on 3 android devices that I have tested on. However, I have written a unit test using junit and Roboelectric that checks if the scrolling has made the the item at the target position visible. The test fails. When I debug, I notice that android.os.Build.VERSION.SDK_INT is 0 when running with Roboelectric (i.e., on the desktop vs. device or emulator).

I’ve tried ignoring the version and just using ListView.smoothScrollToPosition(), but the getFirstVisilePoition() and getLastVisiblePosition() methods continue to return 0, even immediately after I call smoothScrollToPosition(150).

Does anyone know if/how scrolling a listview can be tested using Roboelectric?

Any help would be appreciated – I can’t seem to find any information on the topic.

Thanks,

Ana

Answer 1

If you’re using robolectric 1.1 or 1.2, here is the source for the AbsListView:
https://github.com/pivotal/robolectric/blob/master/src/main/java/com/xtremelabs/robolectric/shadows/ShadowAbsListView.java

It looks like all the scrolling functionality is it ShadowAdapterView:
https://github.com/pivotal/robolectric/blob/master/src/main/java/com/xtremelabs/robolectric/shadows/ShadowAdapterView.java

It doesn’t look like getFirstVisiblePoition() or getLastVisiblePosition() are implemented.

I was able to get the smooth scroll position.

@RunWith(RobolectricTestRunner.class)
public class SmoothScroll {

    @Test
    public void testSmoothScroll() {
        Activity context = new Activity();
        ListView view = new ListView(context);

        view.smoothScrollToPosition(100);
        Assert.assertEquals(100, Robolectric.shadowOf(view).getSmoothScrolledPosition());
    }

}

You can get the smooth scrolled position. Based on the height of the elements, you may be able to work out which ones are visible.