TabularView is a Swift package for iOS/iPadOS (13.0 and above) to display tabular data in a view, in a manner similar to how UICollectionView can display unidimensional data in a grid.
The package supports multiple columns, each with their own optional header and optional footer, indexed by an enumeration type, that you define, rather than an integer, so your code is clearer about which column or columns it refers to. There's also built-in support for sorting rows by a selected column.
The design philosophy is inspired heavily by how UICollectionView works. There are separate data source and delegate protocols (in fact, two delegate protocols, one for layout and another for sorting), and the data source is managed using the new (as of 2019) UICollectionView Diffable Data Source API.
However, one feature that I could not figure out a way to implement, using the APIs out of the box, is pinned headers and footers. You see, in this first release of Compositional Layout, headers and footers (collectively known as boundary supplementary items) can only be added to sections and, additionally, sections aren't composable: you can have groups of items which themselves can be groups but you can't have sections containing other sections.
Therefore, the only way to have per-column headers and footers in a multi-column situation is to have a header row and a footer row, where a row is a group of items. But that means those headers and footers can't be pinned, unless I implemented my own collection view layout subclass, which I wasn't prepared to do at this time.
It also means that each item in a header or footer will be treated just like any other item. As far as the collection view is concerned, there are no headers or footers at all, but only regular cell items. This is why I didn't bother to differentiate between UICollectionViewCell and UICollectionReusableView. In TabularView, data cells, header cells, and footer cells are all instances of UICollectionViewCell, though they can be instances of different subclasses of UICollectionViewCell so that header and footer cells can look and behave differently from data item cells.
But if header and footer cells are just regular cell items, does the data source have to jump through extra hoops to account for them? No. TabularView internally adds an extra row of "data items" for a header and another for a footer, if the client code wants to have a header or footer. As far as the data source is concerned, the number of rows is what it is expected to be.
And speaking of sections, the current version of TabularVIew only supports a single section. It's not too difficult to add support for multiple sections and I'll get to it soon, so stay tuned.
I have a related GitHub project for a demo app showing how to use this package.
There are some video screen captures illustrating
- how to show and hide headers and footers
- how to change the gap between columns
- how to change individual column widths
- how to sort data by selecting a column
- scrolling performance
but they're too large to display inline, so here's a screenshot of the demo app instead:
TabularView is provided only as a Swift Package Manager package, because I'm moving away from CocoaPods and Carthage, and can be easily installed directly from Xcode.
A list of changes is available.
TabularView is available under the MIT license. See the LICENSE file for more info.