Question

我正在使用RecyclerView，我需要使用android espresso获取RecyclerView中的项目总数。我该怎么办？

Answer 1

我会这样做：

@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

在Thekarlo95's answer具体而完整地回答问题的同时，我想展示我的示例，说明如何与Stéphane's method一起使用他的方法来测试特定动作前后的计数差异：

@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)));
}

下面是RecyclerViewItemCountAssertion类的代码（只需将其放在单独的文件中）。请注意，有两个可用的构造函数：

RecyclerViewItemCountAssertion(int expectedCount)-预期为整数类型的参数，使用默认的is匹配器。

RecyclerViewItemCountAssertion(Matcher<Integer> matcher)-类型为Matcher<Integer>的参数，例如is(3)，lessThan(4)等。

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);
    }
}

在浓缩咖啡中获取RecyclerView总项目数

2 个答案: