Android - espresso - clicking on a listview entry based on custom objects

Question

Espresso is used for automatic testing my App.

Edit: below you find a number of answers!

How can I click (within an automated Espresso test script) on an entry in a long list of custom objects?

In the Espresso documentation there is an example of a LongList. Working with a List of objects is what I normally do. Trying many options to step from Map to Object didn't yield good results so far.

The Espresso documentation says a 'onData' should be used. So, something like:

onData( myObjectHasContent("my_item: 50")).perform(click());
onView(withId( R.id.selection_pos2)).check(matches(withText("50")));

My questions (and I think they are helpful for the learning community): - Can you write a good Matcher for this? - How can we use that in the 'onData' ?

What is the situation? On the screen I have a listview of objects like:

public class MyOjbect { 
    public String content; 
    public int    size; 
}

The adapter I use to populate the populated list is:

public class MyObjectWithItemAndSizeAdapter extends ArrayAdapter<MyObjectWithItemAndSize> {
    private final Context context;
    private final List<MyObjectWithItemAndSize> values;
    ...
    @Override
    public View getView(int position, View concertView, ViewGroup parent) {
        View view = null;
        if (concertView != null) {
            view = (LinearLayout) concertView;
        } else {
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            view = inflater.inflate( R.layout.list_item, parent, false);
        } 
        TextView itemT = (TextView) view.findViewById( R.id.item_content);
        itemT.setText( values.get(position).item);
        TextView sizeT = (TextView) view.findViewById( R.id.item_size);
        sizeT.setText( "" + values.get(position).size);
        return view;
    }
 }

Answer 1

The matcher given to onData() must match the desired value returned by Adapter.getItem(int) of the desired ListView.

So in your example, the matcher should be something like this:

public static Matcher<Object> withContent(final String content) {
    return new BoundedMatcher<Object, MyObjectWithItemAndSize>(MyObjectWithItemAndSize.class) {
        @Override
        public boolean matchesSafely(MyObjectWithItemAndSize myObj) {
            return myObj.content.equals(content);
        }

        @Override
        public void describeTo(Description description) {
            description.appendText("with content '" + content + "'");
        }
    };
}