Enabled Fast Scroll disrupts normal scroll flow

[bistaastha]

Summary:
In Explore activity, scrolling through 'Featured' or 'Uploaded via Mobile' has fast scrolling enabled for the GridView. For right-handed scrolling, this GridView scrollbar is often accidentally touched and may lead to an abrupt jump to another image. Also, it is counter-intuitive to normal scrolling.

Steps to reproduce:

• Go to Explore
• Scroll through images in any of the tabs
• The GridView scrollbar is visible on the right side of the screen

Device and Android version:
Moto G (5S) Android 8.1.0 API level 27

Commons app version:
Current master

Screen-shots:

Would you like to work on the issue?
No

[bistaastha]

@nicolas-raoul Can you tag this issue as a good first issue? It is a small change but it would require some digging around.

[maskaravivek]

Yes I have also faced this issue multiple times. Can you do a bit of research and propose possible approaches to tackle it. AFAIK fast scrolling was enabled as these lists could potentially contain 100s of items.

[bistaastha]

@maskaravivek For smaller screen devices and possibly for the ones with a curved edge, I think that fast scroll hinders scrolling more than it helps with it.

[bistaastha]

I'll try to look for other alternatives for fast scroll. Since the section where this is enabled in called Explore, is the functionality for skipping to certain parts of the scroll flow really required?

[maskaravivek]

I am not sure if we would be able to detect curved edges of the device and disable fast scrolling just for those devices.

Currently, the scroll bar is very thick. Can you check if decreasing the scrollbar width to 1px or helps? Also, maybe we can set android:fadeScrollbars:true so that it is not visible at all times.

It would be great if could check these approaches and maybe any other approach that comes to your mind. We can then finalize what fix should be used.

[bistaastha]

I tried fading the scrollbar, but accidental touches still managed to activate it. It will be some time before I will be able to check out the scrollbar after decreasing the width.

[avivith]

Hi. Is this issue solved already, or should I work on it?

[bistaastha]

Hi @avivith. This hasn't been resolved yet.

The fast scrollbar's height and width can be customized by making custom drawables (referene) .

@maskaravivek Reducing the width using this method might be a possible approach to solving the problem of accidental touches.

[avivith]

Sadly, I'm a little sick and don't manage to work currently. I hope someone else would solve this issue.

[318anushka]

I'd like to give this a try if no one is working on it.
@maskaravivek can you assign this to me.

[318anushka]

I have enabled fast scroll only when user actually scrolls(state is changed) so even if you accidentally touch scroll bar it wouldn't lead to abrupt jump or disrupt normal scroll.