Fasthub: The scrolling bar keeps resizing

Created on 4 Jun 2017 · 12Comments · Source: k0shk0sh/FastHub

App Version: 3.0.0

OS Version: 25

Model: Samsung Galaxy S5

When you're scrolling through an issue with a lot of comments like this one, the scrolling bar (or FastScroller, as you like to call it) keeps jumping around.

_Sent from my Samsung kminilte using FastHub_

Won't Fix

Source

ghost

All 12 comments

Attaching a GIF
2017-06-04_13-20-13

yakov116 on 4 Jun 2017

@yakov116 Yeah that's what I meant

_Sent from my Samsung kminilte using FastHub_

_Sent from my Samsung Galaxy S5 using FastHub_

ghost on 4 Jun 2017

👍1

Well, its because each comment has its own length plush the timeline has plenty of different rows, header, labels, comments. So it will definitely do that. Its what any fastscroller do.

_Sent from my Htc m8 using FastHub_

k0shk0sh on 5 Jun 2017

@k0shk0sh But couldn't you just calculate the sum of all the lengths of all the comments?

_Sent from my Samsung Galaxy S5 using FastHub_

ghost on 5 Jun 2017

@StanNL for what reason exactly? as I said, when you have such complex multi-row list, you gonna have such thing.

k0shk0sh on 5 Jun 2017

@k0shk0sh Well, I'm not a Java expert, nor an app developer at all, but I'd say it would look better if it was more consistent and it wouldn't be jumping from place to place all the time

_Sent from my Samsung Galaxy S5 using FastHub_

ghost on 5 Jun 2017

That would indeed be nice but hardly if even not possible to implement; the thing is the app uses a so-called _RecyclerView_ which is basically a box with scrollable content that is based on the same layout. Only the content that is actually visible to the user is also in the view hierarchy which means in this example comments that are not visible practically do not exist at all.
Because of that the RecyclerView, which only knows the total amount of comments and the height of the currently visible ones, has to assume all items have a similar height; it can't detect that there is for example one very big one in between because, as said, it doesn't exist as a view. The only way to detect the total height would be to add views for _all_ comments which is extremely expensive.
Theoretically there are also other ways to determine the height but all of them require very complex code or are also expensive so it's best to just leave it that way. Oh, and I think you can't even manually set the scrollbar position or dimensions from outside.