At this moment the user can tap to open the sheet but we also need to provide an option to hold the sheet and manually move it to the top. There are two things we have to keep in mind. The first one is to update the sheet’s height alongside drag updates. The second one is to finish the animation once the user has finished the gesture (he or she can just snap and expect the sheet to get expanded).

Luckily for us, this behavior was implemented in Google’s Gallery App which is open-sourced, so we can borrow the gesture handling from the Google team and use it in our app. 🙂