An Android Espresso ViewAction that flashes the background color of a View.

FlashActions

import android.graphics.Color;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.support.test.espresso.UiController;
import android.support.test.espresso.ViewAction;
import android.view.View;

import org.hamcrest.Matcher;

import static android.support.test.espresso.matcher.ViewMatchers.isDisplayed;

public class FlashActions {

    public static ViewAction flashView(int count) {
        return new FlashViewAction(count);
    }

    public static ViewAction flashView() {
        return new FlashViewAction(4);
    }

    static class FlashViewAction implements ViewAction {
        private int mCount;

        public FlashViewAction(int count) {
            mCount = count;
        }

        @Override
        public String getDescription() {
            return "flash view";
        }

        @Override
        public Matcher<View> getConstraints() {
            return isDisplayed();
        }

        @Override
        public void perform(UiController uic, View view) {
            Drawable bgDrawable = view.getBackground();

            for (int i = 0; i < mCount; i++) {
                view.setBackgroundColor(Color.RED);
                uic.loopMainThreadForAtLeast(250);
                view.setBackgroundColor(Color.GREEN);
                uic.loopMainThreadForAtLeast(250);
            }
            view.setBackgroundColor(Color.TRANSPARENT);

            if (bgDrawable != null) {
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                    view.setBackground(bgDrawable);
                }
            }
        }
    }

}