在浓缩咖啡中获取RecyclerView总项目数

Question

I am using RecyclerView and i need to get the total count of items in the RecyclerView using android espresso. How can i do it ?

Answer 1

I would do it like this:

@Rule
public ActivityTestRule<MyClass> activityRule = new ActivityTestRule(MyActivity.class);

@Test
public void myTest() {
    RecyclerView recyclerView = activityRule.getActivity().findViewById(R.id.my_recyclerview)
    int itemCount = recyclerView.getAdapter().getItemCount();
}

Answer 2

While Thekarlo95's answer specifically and fully answers the question, I would like to show my example on how to use his method together with Stéphane's method to test a difference in count before and after specific action:

@Test
public void FilterClickShouldChangeRecyclerViewCount() {
    // Get items count before action
    RecyclerView recyclerView = mActivityTestRule.getActivity().findViewById(R.id.recycler_view);
    int countBefore = Objects.requireNonNull(recyclerView.getAdapter()).getItemCount();
    Log.e("count", "Items count before: " + countBefore);

    // Perform action
    ViewInteraction actionMenuItemView = onView(
            allOf(
                    withId(R.id.action_filter),
                    withContentDescription("Show Favorites")));
    actionMenuItemView.perform(click());

    // Verify that items count has changed
    onView(withId(R.id.recycler_view))
            // Instead of 'not', you can use any other hamcrest Matcher like 'is', 'lessThan' etc.
            .check(new RecyclerViewItemCountAssertion(not(countBefore)));
}

And below is a code for RecyclerViewItemCountAssertion class (just put it on a separate file). Note there are two constructors available:

1. RecyclerViewItemCountAssertion(int expectedCount) - parameter of type integer is expected, default is matcher is used.

2. RecyclerViewItemCountAssertion(Matcher<Integer> matcher) - parameter of type Matcher<Integer> is expected, like is(3) , lessThan(4) etc.

    public class RecyclerViewItemCountAssertion implements ViewAssertion { private final Matcher<Integer> matcher; public RecyclerViewItemCountAssertion(int expectedCount) { this.matcher = is(expectedCount); } public RecyclerViewItemCountAssertion(Matcher<Integer> matcher) { this.matcher = matcher; } @Override public void check(View view, NoMatchingViewException noViewFoundException) { if (noViewFoundException != null) { throw noViewFoundException; } RecyclerView recyclerView = (RecyclerView) view; RecyclerView.Adapter adapter = recyclerView.getAdapter(); assert adapter != null; assertThat(adapter.getItemCount(), matcher); } }