Espresso - get text of element

You should create a matcher to access to that element value.

For instance, you can check if it's text has some value:

Matcher<View> hasValueEqualTo(final String content) {

    return new TypeSafeMatcher<View>() {

        @Override
        public void describeTo(Description description) {
            description.appendText("Has EditText/TextView the value:  " + content);
        }

        @Override
        public boolean matchesSafely(View view) {
            if (!(view instanceof TextView) && !(view instanceof EditText)) {
                    return false;
            }
            if (view != null) {
                String text;
                if (view instanceof TextView) {
                    text = ((TextView) view).getText().toString();
                } else {
                    text = ((EditText) view).getText().toString();
                }

                return (text.equalsIgnoreCase(content));
            }
            return false;
        }
    };
}

And call it this way:

onView(withId(R.id.medical_summary_text_view))
    .check(matches(hasValueEqualTo(value)));

or you can edit this matcher to return just whether the text is empty or not:

Matcher<View> textViewHasValue() {

    return new TypeSafeMatcher<View>() {

        @Override
        public void describeTo(Description description) {
            description.appendText("The TextView/EditText has value");
        }

        @Override
        public boolean matchesSafely(View view) {
            if (!(view instanceof TextView) && !(view instanceof EditText)) {
                    return false;
            }
            if (view != null) {
                String text;
                if (view instanceof TextView) {
                    text = ((TextView) view).getText().toString();
                } else {
                    text = ((EditText) view).getText().toString();
                }

                return (!TextUtils.isEmpty(text));
            }
            return false;
        }
    };
}

And call it this way:

onView(withId(R.id.medical_summary_text_view))
    .check(matches(textViewHasValue()));

You can get the text of the ViewInteraction by the following function:

fun getText(matcher: ViewInteraction): String {
    var text = String()
    matcher.perform(object : ViewAction {
        override fun getConstraints(): Matcher<View> {
            return isAssignableFrom(TextView::class.java)
        }

        override fun getDescription(): String {
            return "Text of the view"
        }

        override fun perform(uiController: UiController, view: View) {
            val tv = view as TextView
            text = tv.text.toString()
        }
    })

    return text
}

val numberResult: ViewInteraction = onView(withId(R.id.txNumberResult))
var searchText = getText(numberResult)