Reorder tracks in the queue

[nt4f04uNd]

Suggestion

Currently this is not implemented, because we use itemExtent.

We must use it:

• for scrollbar
• for jumps when user closes the queue route

Otherwise it's just very laggy.

However, itemExtent is broken for ReordableList flutter/flutter#84901

So it poses a dilemma, where we can only use one or another.

Possible solutions:

1. (The most desirable option) Fix flutter/flutter#84901

I tried digging this, but it seems that the issue is deeply in the underlying SliverFixedExtentList, which lays all of its children with the fixed extent height. ReordableList inserts an empty box when moving a child, which in this protocol means that extra space will appear.

The solution could involve either

1. trying to figure out why is this extra empty box even there and removing it
2. adding a hook to SliverFixedExtentList to manipulate a height of a singular item (which seems extremely hard)

2. Try exploring the https://pub.dev/packages/great_list_view package

This is a cat in a bag option.

AFAIK this package uses techniques from native RecyclerView Android implementation, which allows for reordering, fast jumping to particular item, even if the list is not of fixed height, and other cool features.

But this is an unexplored third party dependency that could potentially become unmaintained, or just containt bugs we don't know of.

3. Hack it

Come up with some hack, for example: in selection the list is changed to ReordableList without itemExtent and then changed back to a regular one when selection ends.