PhotoView in ViewPager "jumping" issue

Hello, I have noticed an issue when using PhotoView with ViewPager. When zoomed in and you try to navigate to the next page, the PhotoView is first scrolled to the edge as expected, but after that the next ViewPager page just sort of jumps into view. I also recorded a gif to demonstrate this issue: https://media.giphy.com/media/xyH3Dqr5mZroI/giphy.gif

I realise, that this is also ViewPager's (VP) fault because it intercepts the DOWN event which is actually meant for the PhotoView (PV) and when PV starts passing MOVE events to the VP then VP just thinks that the person has dragged the screen really fast.

Do you think this is something PV could address? I would suggest starting to pass MOVE events to the parent only if PV is already scrolled to the edge when the DOWN event occurs - then the DOWN event that VP intercepts would actually be with the correct X and Y.

Start by reproducing the reported interaction with PhotoView inside Android ViewPager, using the linked GIF as the behavioral reference. Read the PhotoView and ViewPager touch-event handling paths, then verify that navigating from a zoomed edge no longer causes the next page to jump.

Scritto dal modello di indicizzazione a partire dal testo della issue.