This app is Haptic Feedback Checker, for Android App developer. Please check "Implements" in menu, how to implement Haptic Feedback. I don't understand how vibrate my device when I'm developing Android app using HapticFeedbackConstants. And I searched Haptic Feedback Checker on Google Play, but I can't find it. So, I made this app. Recommend: up to Android 8.0 Pixel smartphone (ex. Pixel2, Pixel 5a...)