Invalid target position when scrolling about discretescrollview

[youfacepalm]

The currentPosition was -1 before the crash in DiscreteScrollLayoutManager startSmoothPendingScroll method

[yarolegovich]

Thanks for the report, unfortunately I won't be able to look into it until weekends.

[youfacepalm]

Hey no problem at all. I traced down the issue and found out it is caused by how the DiscreteScrollView is placed in the layout. I have created a sample project that can reproduce the crash. I hope it saves you some time.

https://drive.google.com/open?id=0B4VSgmZteixRX002ZDVYR1c0RnM

Thanks again for all the effort!

[yarolegovich]

Yeah, the issue exists, I've checked the project. Can't yet say why it happens.
You started getting it after upgrading to 1.3?

[youfacepalm]

It happened even before 1.3

[bearprada]

I found the root cause might come from DiscreteScrollLayoutManager.onScrollEnd()

        Direction scrollDirection = Direction.fromDelta(scrolled);
        if (Math.abs(scrolled) == scrollToChangeCurrent) {
            currentPosition += scrollDirection.applyTo(1); <- it will return -1 if the recyclerview has zero items
            scrolled = 0;
        }

[yarolegovich]

@youfacepalm thanks a lot for the project you created, it saved me a lot of time. The issue is resolved.