SwiftTabler

A multi-platform SwiftUI component for tabular data.

Available as an open source library to be incorporated in SwiftUI apps.

SwiftTabular is part of the OpenAlloc family of open source Swift software tools.

macOS	iOS

Features

• Convenient display of tabular data from RandomAccessCollection data sources
• Presently targeting macOS v11+ and iOS v14+*
• Supporting both value and reference semantics (including Core Data, which uses the latter)
• Option to support a bound data source, where inline controls can directly mutate your data model
• Support for single-select, multi-select, or no selection
• Option to specify a header and/or footer
• Option to sort by column in header/footer, with indicators and concise syntax
• Option to specify a row background and/or overlay
• On macOS, option for hover events, such as to highlight row under the mouse cursor
• MINIMAL use of View erasure (i.e., use of AnyView), which can impact scalability and performance**
• No external dependencies!

Three table types are supported, as determined by the mechanism by which their header and rows are rendered.

List

• Based on SwiftUI's List
• Option to support moving of rows through drag and drop
• Header/Footer are inside scrolling region

Stack

• Based on ScrollView/LazyVStack
• Header/Footer are outside scrolling region

Grid

• Based on ScrollView/LazyVGrid
• Likely the most scalable and efficient, but least flexible
• Header/Footer are outside scrolling region

* Other platforms like macCatalyst, iPad on Mac, watchOS, tvOS, etc. are poorly supported, if at all. Please contribute to improve support!

** AnyView only used to specify sort images in configuration, which shouldn't impact scalability.

Tabler Example

The example below shows the display of tabular data from an array of values using TablerList, a simple variant based on List.

import SwiftUI
import Tabler

struct Fruit: Identifiable {
    var id: String
    var name: String
    var weight: Double
    var color: Color
}

struct ContentView: View {

    @State private var fruits: [Fruit] = [
        Fruit(id: "🍌", name: "Banana", weight: 118, color: .brown),
        Fruit(id: "🍓", name: "Strawberry", weight: 12, color: .red),
        Fruit(id: "🍊", name: "Orange", weight: 190, color: .orange),
        Fruit(id: "🥝", name: "Kiwi", weight: 75, color: .green),
        Fruit(id: "🍇", name: "Grape", weight: 7, color: .purple),
        Fruit(id: "🫐", name: "Blueberry", weight: 2, color: .blue),
    ]
    
    private var gridItems: [GridItem] = [
        GridItem(.flexible(minimum: 35, maximum: 40), alignment: .leading),
        GridItem(.flexible(minimum: 100), alignment: .leading),
        GridItem(.flexible(minimum: 40, maximum: 80), alignment: .trailing),
        GridItem(.flexible(minimum: 35, maximum: 50), alignment: .leading),
    ]

    private typealias Context = TablerContext<Fruit>

    private func header(ctx: Binding<Context>) -> some View {
        LazyVGrid(columns: gridItems) {
            Text("ID")
            Text("Name")
            Text("Weight")
            Text("Color")
        }
    }
    
    private func row(fruit: Fruit) -> some View {
        LazyVGrid(columns: gridItems) {
            Text(fruit.id)
            Text(fruit.name).foregroundColor(fruit.color)
            Text(String(format: "%.0f g", fruit.weight))
            Image(systemName: "rectangle.fill").foregroundColor(fruit.color)
        }
    }

    var body: some View {
        TablerList(header: header,
                   row: row,
                   results: fruits)
    }
}

While LazyVGrid is used here to wrap the header and row items, you could alternatively wrap them with HStack or similar mechanism.

Tabler Views

Tabler offers twenty-seven (27) variants of table views from which you can choose. They break down along the following lines:

• Table View - the View name
• Type - each of the three table types differ in how they render:
  • List - based on List
  • Stack - based on ScrollView/LazyVStack
  • Grid - based on ScrollView/LazyVGrid
• Select - single-select, multi-select, or no selection
• Value - if checked, can be used with value types (e.g., struct values)
• Reference - if checked, can be used with reference types (e.g., class objects, Core Data, etc.)
• Bound - if checked, can be used with inline controls (TextField, etc.) to mutate model
• Filter - if checked, config.filter is supported (see caveat below)

Table View	Type	Select	Value	Reference	Bound	Filter
TablerList	List		✓	✓		✓
TablerListB	List		✓		✓	✓*
TablerListC	List			✓	✓
TablerList1	List	Single	✓	✓		✓
TablerList1B	List	Single	✓		✓	✓*
TablerList1C	List	Single		✓	✓
TablerListM	List	Multi	✓	✓		✓
TablerListMB	List	Multi	✓		✓	✓*
TablerListMC	List	Multi		✓	✓
TablerStack	Stack		✓	✓		✓
TablerStackB	Stack		✓		✓	✓*
TablerStackC	Stack			✓	✓
TablerStack1	Stack	Single	✓	✓		✓
TablerStack1B	Stack	Single	✓		✓	✓*
TablerStack1C	Stack	Single		✓	✓
TablerStackM	Stack	Multi	✓	✓		✓
TablerStackMB	Stack	Multi	✓		✓	✓*
TablerStackMC	Stack	Multi		✓	✓
TablerGrid	Grid		✓	✓		✓
TablerGridB	Grid		✓		✓
TablerGridC	Grid			✓	✓
TablerGrid1	Grid	Single	✓	✓		✓
TablerGrid1B	Grid	Single	✓		✓
TablerGrid1C	Grid	Single		✓	✓
TablerGridM	Grid	Multi	✓	✓		✓
TablerGridMB	Grid	Multi	✓		✓
TablerGridMC	Grid	Multi		✓	✓

* filtering with bound values likely not scalable as implemented. If you can find a better way to implement, please submit a pull request!

Header/Footer

Optionally attach a header (or footer) to your table:

var body: some View {
    TablerList(header: header,
               footer: footer,
               row: row,
               results: fruits)
}

private func header(ctx: Binding<Context>) -> some View {
    LazyVGrid(columns: gridItems) {
        Text("ID")
        Text("Name")
        Text("Weight")
        Text("Color")
    }
}

private func footer(ctx: Binding<Context>) -> some View {
    LazyVGrid(columns: gridItems) {
        Text("ID")
        Text("Name")
        Text("Weight")
        Text("Color")
    }
}

Where you don't want a header (or footer), simply omit from the declaration of the table.

For List based variants, the header and footer are inside the scrolling region. For Stack and Grid based variants, they are outside. (This may be configurable at some point once any scaling/performance issues are resolved.)

Column Sorting

Column sorting is available through the tablerSort view function.

The examples below show how the header items can support sort.

.columnTitle() is a convenience function that displays header name along with an indicator showing the current sort state, if any. Alternatively, build your own header and call the .indicator() method to get the active indicator image.

Caret images are used by default for indicators, but are configurable (see Configuration section below).

Random Access Collection

From the TablerDemo app:

private typealias Context = TablerContext<Fruit>
private typealias Sort = TablerSort<Fruit>

private func header(ctx: Binding<Context>) -> some View {
    LazyVGrid(columns: gridItems) {
        Sort.columnTitle("ID", ctx, \.id)
            .onTapGesture { tablerSort(ctx, &fruits, \.id) { $0.id < $1.id } }
        Sort.columnTitle("Name", ctx, \.name)
            .onTapGesture { tablerSort(ctx, &fruits, \.name) { $0.name < $1.name } }
        Sort.columnTitle("Weight", ctx, \.weight)
            .onTapGesture { tablerSort(ctx, &fruits, \.weight) { $0.weight < $1.weight } }
        Text("Color")
    }
}

Core Data

The sort method used with Core Data differs. From the TablerCoreDemo app:

private typealias Context = TablerContext<Fruit>
private typealias Sort = TablerSort<Fruit>

private func header(ctx: Binding<Context>) -> some View {
    LazyVGrid(columns: gridItems, alignment: .leading) {
        Sort.columnTitle("ID", ctx, \.id)
            .onTapGesture { fruits.sortDescriptors = [tablerSort(ctx, \.id)] }
        Sort.columnTitle("Name", ctx, \.name)
            .onTapGesture { fruits.sortDescriptors = [tablerSort(ctx, \.name)] }
        Sort.columnTitle("Weight", ctx, \.weight)
            .onTapGesture { fruits.sortDescriptors = [tablerSort(ctx, \.weight)] }
    }
}

Sorting on a computed column

Where there is no key path available to store in the sort context, such as for a computed value, create a place holder key path.

extension Holding {
    func getMarketValue(_ priceMap: [String: Double]) -> Double {
        shareCount * (priceMap[ticker] ?? 0)
    }

    var marketValuePlaceholder: Double { 0 }
}

struct HoldingsTable: View {
    private typealias Context = TablerContext<Holding>
    
    private func header(_ ctx: Binding<Context>) -> some View {
        LazyVGrid(columns: gridItems) {
            // ...
            Sort.columnTitle("Market Value", ctx, \.marketValuePlaceholder)
                .onTapGesture {
                    tablerSort(ctx, &model.holdings, \.marketValuePlaceholder) { 
                        $0.getMarketValue(priceMap) < $1.getMarketValue(priceMap) 
                    }
                }
        }
    }
}

Bound data

macOS	iOS

When used with 'bound' views (e.g., TablerListB or TablerListC), the data can be modified directly, mutating your data source. From the demo:

private func brow(fruit: BoundValue) -> some View {
    LazyVGrid(columns: gridItems) {
        Text(fruit.wrappedValue.id)
        TextField("Name", text: fruit.name)
            .textFieldStyle(.roundedBorder)
        Text(String(format: "%.0f g", fruit.wrappedValue.weight))
        ColorPicker("Color", selection: fruit.color)
            .labelsHidden()
    }
}

For value sources, BoundValue is a binding:

typealias BoundValue = Binding<Fruit>

For reference sources, including Core Data, BoundValue is an object wrapper (aka 'ProjectedValue'):

typealias BoundValue = ObservedObject<Fruit>.Wrapper

Note that for Core Data, the user's changes will need to be saved to the Managed Object Context. See the TablerCoreDemo code for an example of how this might be done.

Row Background

You have the option to specify a row background, such as to impart information, or as a selection indicator.

Row Background, as the name suggests, sits BEHIND the row.

macOS	iOS

An example of using row background to impart information, as shown above:

var body: some View {
    TablerList(header: header,
               row: row,
               rowBackground: rowBackground,
               results: fruits)
}

private func rowBackground(fruit: Fruit) -> some View {
    LinearGradient(gradient: .init(colors: [fruit.color, fruit.color.opacity(0.2)]),
                   startPoint: .top, 
                   endPoint: .bottom)
}

An example of a selection indicator using row background, such as for Stack based tables which do not have a native selection indicator:

@State private var selected: Fruit.ID? = nil

var body: some View {
    TablerStack1(header: header,
                 row: row,
                 rowBackground: rowBackground,
                 results: fruits,
                 selected: $selected)
}

private func rowBackground(fruit: Fruit) -> some View {
    RoundedRectangle(cornerRadius: 5)
        .fill(fruit.id == selected ? Color.accentColor : Color.clear)
}

Row Overlay

Similar to a row background, an overlay can be used to impart information, or to use as a selection indicator.

Row overlay, as the name suggests, sits ATOP the row.

An example of a selection indicator using row overlay:

@State private var selected: Fruit.ID? = nil

var body: some View {
    TablerStack1(header: header,
                 row: row,
                 rowOverlay: rowOverlay,
                 results: fruits,
                 selected: $selected)
}

private func rowOverlay(fruit: Fruit) -> some View {
    RoundedRectangle(cornerRadius: 5)
        .strokeBorder(fruit.id == selected ? .white : .clear,
                      lineWidth: 2,
                      antialiased: true)
}

Hover Events

For macOS only, you can capture hover events, typically to highlight the row under the mouse cursor.

@State private var hovered: Fruit.ID? = nil

var body: some View {
    TablerList(.init(onHover: hoverAction),
               header: header,
               row: row,
               rowBackground: rowBackground,
               results: fruits)
}

private func rowBackground(fruit: Fruit) -> some View {
    RoundedRectangle(cornerRadius: 5)
        .fill(Color.accentColor.opacity(hovered == fruit.id ? 0.2 : 0.0))
}

private func hoverAction(fruitID: Fruit.ID, isHovered: Bool) {
    if isHovered { hovered = fruitID } else { hovered = nil }
}

To coordinate hover with other backgrounds, such as for selection on Stack tables, see the demo apps.

Moving Rows

Row moving via drag and drop is available for the List based variants.

An example for use with Random Access Collections, as seen in TablerDemo:

var body: some View {
    TablerList(.init(onMove: moveAction),
               row: row,
               results: fruits)
}

private func moveAction(from source: IndexSet, to destination: Int) {
    fruits.move(fromOffsets: source, toOffset: destination)
}

TODO need Core Data example, if it's possible to do so.

Configuration

var body: some View {
    TablerList(.init(onMove: moveAction,
                     filter: { $0.weight > 10 },
                     onHover: hoverAction),
               header: header,
               row: row,
               results: fruits)
}

Configuration options will vary by table type.

Defaults can vary by platform (macOS, iOS, etc.). See the code for specifics.

Spacing defaults are driven by the goal of achieving uniform appearance among table types, with the List type serving as the standard.

Base Defaults

Base defaults are defined in the TablerConfig module.

• tablePadding: EdgeInsets - no padding
• sortIndicatorForward: AnyView - "chevron.up" image
• sortIndicatorReverse: AnyView - "chevron.down" image
• sortIndicatorNeutral: AnyView - "chevron.up" image, with opacity of 0

List

List configuration is optional.

TablerListConfig<Element>.init parameters:

• canMove: CanMove<Element> - with a default of { _ in true }, allowing any row to move (if onMove defined)
• canDelete: CanDelete<Element> - with a default of { _ in true }, allowing any row to be deleted (if onDelete defined), currently only via swipe menu on iOS
• onMove: OnMove<Element>? - with a default of nil, prohibiting any move
• onDelete: OnDelete<Element>? - with a default of nil, prohibiting any delete, currently only via swipe menu on iOS
• filter: Filter? - with a default of nil, indicating no filtering
• onHover: (Element.ID, Bool) -> Void - defaults to { _,_ in }
• tablePadding: EdgeInsets - per Base defaults
• sortIndicatorForward: AnyView - per Base defaults
• sortIndicatorReverse: AnyView - per Base defaults
• sortIndicatorNeutral: AnyView - per Base defaults

Stack

Stack configuration is optional.

TablerStackConfig<Element>.init parameters:

• rowPadding: EdgeInsets - Stack-specific defaults; varies by platform
• headerSpacing: CGFloat - default varies by platform
• footerSpacing: CGFloat - default varies by platform
• rowSpacing: CGFloat - default of 0
• filter: Filter? - with a default of nil, indicating no filtering
• onHover: (Element.ID, Bool) -> Void - defaults to { _,_ in }
• tablePadding: EdgeInsets - default varies by platform
• sortIndicatorForward: AnyView - per Base defaults
• sortIndicatorReverse: AnyView - per Base defaults
• sortIndicatorNeutral: AnyView - per Base defaults

Grid

Grid configuration is required, where you supply a GridItem array.

TablerGridConfig<Element>.init parameters:

• gridItems: [GridItem] - required
• alignment: HorizontalAlignment - LazyVGrid alignment, with a default of .leading
• itemPadding: EdgeInsets - Grid-specific defaults, varies by platform
• headerSpacing: CGFloat - default varies by platform
• footerSpacing: CGFloat - default varies by platform
• rowSpacing: CGFloat - default of 0
• filter: Filter? - with a default of nil, indicating no filtering
• onHover: (Element.ID, Bool) -> Void - defaults to { _,_ in }
• tablePadding: EdgeInsets - default varies by platform
• sortIndicatorForward: AnyView - per Base defaults
• sortIndicatorReverse: AnyView - per Base defaults
• sortIndicatorNeutral: AnyView - per Base defaults

Horizontal Scrolling

On compact displays you may wish to scroll the table horizontally.

You can wrap in your own ScrollView, or alternatively import the SwiftSideways package:

import Tabler
import Sideways

var body: some View {
    TablerList(header: header,
               row: row,
               results: fruits)
        .sideways(minWidth: 400)
}

AutoInit Code Generation

This applies only to those forking and customizing the Tabler code.

Many additional init() functions for each table variant are generated via the code template Templates/AutoInit.stencil.

To regenerate and re-format, run the Sourcery command from the project directory.

$ brew install sourcery
$ sourcery
$ brew install swiftformat
$ swiftformat **/*.swift   

The generated code will be found in the Sources/Generated directory.

See Also

• SwiftSideways - minimal horizontal scroller wrapper

Apps demonstrating Tabler:

• TablerDemo - basic use of Tabler
• TablerCoreDemo - use of Tabler with Core Data sources

This library is a member of the OpenAlloc Project.

• OpenAlloc - product website for all the OpenAlloc apps and libraries
• OpenAlloc Project - Github site for the development project, including full source code

License

Copyright 2021, 2022 OpenAlloc LLC

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Contributing

Contributions are welcome. You are encouraged to submit pull requests to fix bugs, improve documentation, or offer new features.

The pull request need not be a production-ready feature or fix. It can be a draft of proposed changes, or simply a test to show that expected behavior is buggy. Discussion on the pull request can proceed from there.