BaseComponents

Introduction

BaseComponents aims to provide easily reusable and understandable components to increase productivity with UIKit. Formerly written in Objective-C and used extensively in production, the time has come to transition to Swift.

Components

Layout

ConditionalLayoutView

Adjust the order, size and selection of subviews based on traitCollections, userInterfaceIdiom, screen size or any other condition. The actual layout is performed by a SplitView instance.

First Steps

Use addConditionalLayoutView() on any UIView. To add conditional layout paths use addSubviews() and return true if a layout condition is met.

Code Sample

view.addConditionalLayoutView { (conditionalLayoutView) in
    let redView = UIView().color(.background, .red)
    let greenView = UIView().color(.background, .green)
    let blueView = UIView().color(.background, .blue)

    conditionalLayoutView.addSubviews({ (targetView) in
        targetView.addSubview(redView, layoutType: .equal)
        targetView.addSubview(greenView, layoutType: .equal)
        targetView.addSubview(blueView, layoutType: .equal)
    }) { (traitCollection) -> Bool in
        return traitCollection.horizontalSizeClass == .compact || traitCollection.horizontalSizeClass == .unspecified
    }

    conditionalLayoutView.addSubviews({ (targetView) in
        targetView.addSubview(greenView, layoutType: .percentage, value: 30, edgeInsets: .init(horizontal: 10))
        targetView.addSubview(redView, layoutType: .percentage, value: 70)
    }) { (traitCollection) -> Bool in
        return traitCollection.horizontalSizeClass == .regular
    }
}

---

ScrollingView

A subclass of UIScrollView to programatically layout subviews in a given direction. The size of a subview along a horizontal or vertical direction can be determined automatically, e.g. UILabel , or by providing a fixed point value.

First Steps

Use addScrollingView() on any UIView.

Code Sample

view.addScrollingView { (scrollingView) in
    let label = UILabel("Large Title").size(.largeTitle, .bold)
    scrollingView.addSubview(label, edgeInsets: .init(horizontal: 15))

    let contentView = UIView().color(.background, .red)
    scrollingView.addSubview(contentView, layoutType: .fixed, value: 500)

    let footerView = UIView().color(.background, .blue)
    scrollingView.addSubview(footerView, layoutType: .fixed, value: 400)
}

---

SplitView

Divide the available width or height of a UIView amongst its subviews programmatically.

First Steps

Use addSplitView() on any UIView.

Code Sample

view.addSplitView { (splitView) in
    splitView.direction = .vertical
    
    splitView.addSubview(UIView().color(.background, .red), layoutType: .equal)
    splitView.addSubview(UIView().color(.background, .blue), layoutType: .equal)
    splitView.addSubview(UIView().color(.background, .green), layoutType: .fixed, value: 44)
}

---

Storage

DiskData

Store and retrieve Codable objects, images, strings or data on the local file system. Has the ability to compress directories into a .zip archive.

First Steps

Create an instance of File or Directory. Use save() to store data.

Code Sample

let file = File(name: "helloWorld.txt")
file.save("Hello World!")
if let content = file.read(as: String.self) {
    print("File read", content)
}
file.delete()

---

CloudKitData

Store and retrieve objects conforming to CloudKitDataCodable in CloudKit.

First Steps

Create a class conforming to the CloudKitDataCodable protocol. Create an instance of CloudKitDataProvider to perform CRUD operations on objects. When first trying to query objects, attributes will have to be adjusted in the CloudKit Dashboard. Check the error parameter in the completionHandler for more information.

Code Sample

class Note: CloudKitDataCodable {
    var record: CloudKitRecord?
    func searchableKeywords() -> String? {
        return text
    }
    
    var text: String = ""
}

let dataProvider: CloudKitDataProvider = CloudKitDataProvider(.public)

let note = Note()
note.text = "Hello World"
dataProvider.save(note) { (storedNote, error) in
    if error != nil {
        print("Error storing note, try again?")
    }
    if let storedNote = storedNote {
        print("Note saved with id:", storedNote.record?.id)
    }
}

---

Networking

NetFetch

Create network requests that can be sent immediately or added to a queue. Convert a response into an object using bind().

First Steps

Create a NetFetchRequest and call fetch()

Code Sample

NetFetchRequest(urlString: "https://twitter.com/mmackh") { (response) in
    print(response.string())
}.fetch()

---

Dates & Time

TimeKeep

Adds conveniece methods to Swift's Date in order to calculate time spans, add or remove time units and get formatted strings.

First Steps

Create a Date and call remove() or add() to modify using time units. Use format() to retrieve a string.

Code Sample

let date = Date()
print(date.remove(.month(1)).dates(until: date))
print("In 7 seconds", date.add(.second(7)).format())

let past = date.remove(.year(5)).startOf(.month)
print(past.format(string: "EEEE, YYYY-MM-dd"))

---

UIKit Helpers

ControlClosures

Adds closures for actions and delegates to UIControl, UIGestureRecognizer, UIBarButtonItem, UITextField, UISearchBar, etc.

First Steps

Create a UIButton and addAction for the desired control event.

Code Sample

let button = UIButton(title: "Tap me!", type: .system)
button.addAction(for: .touchUpInside) { (button) in
    print("Hello World!")
}

---

Conveniences

Chainable properties for popular UIKit methods. Populate an UIImageView with remote images. Introduces many other conveniences.

Code Sample

let label = UILabel("Hello World!")
    .size(.largeTitle, .bold)
    .color(.text, .blue)
    .color(.background, .white)
    .align(.center)

---

Geometry

Adds shortcuts to UIView, CGRect & UIEdgeInsets for manually managing frames.

Code Sample

let label = UILabel("Hello World!")
label.x = 10
label.y = 10
label.width = 200
label.height = 300

let view = UIView().width(50).height(50)

---

DataRender

Avoid writing boilerplate and common pitfalls when displaying data in a UITableView or UICollectionView. Supports fast and accurate automatic cell sizing with ScrollingView.

First Steps

Create a UITableViewCell or UICollectionView subclass and overwrite bindObject(). Create an instance of DataRenderConfiguration and use it to init DataRender. Finally call renderArray().

Automatic Height for UITableViewCell

• Implement itemAutomaticRowHeightCacheKeyHandler() on your DataRender instance
• Add a ScrollingView as the first subview of the cell's contentView, i.e. contentView.addScrollingView().
• To accurately measure the required height, safeAreaInsets and layoutMargins for every object in advance, an invisible child UITableView is added the provided UITableViewCell subclass. To recalculate a height based on new information or user action recalculateAutomaticHeight()

Code Sample

class Cell: UITableViewCell {
    override func bindObject(_ obj: AnyObject) {
        textLabel?.text = obj as? String
    }
}

lazy var dataRender: DataRender = {
    let config = DataRenderConfiguration(cellClass: Cell.self)
    let render = DataRender(configuration: config)
    render.adjustInsets = true
    render.onSelect { (itemRenderProperties) in
        print("Tapped:",itemRenderProperties.object)
    }
    view.addSubview(render)
    return render
}()

override func viewDidLoad() {
    super.viewDidLoad()

    dataRender.renderArray(["Hello","World"])
}

---

KeyboardManager

Repositions and resizes a SplitView instance to avoid overlapping issues caused by the keyboard.

Code Sample

KeyboardManager.manage(rootView: view, resizableChildSplitView: splitView)

---

DebugController

Test ViewControllers by implementing register once and calling open() on DebugController. To quickly jump to a registered ViewController call debugRegisteredViewController in the completionHandler of open() - a shortcut that can be used when the app is launched.

Code Sample

DebugController.register(name: "ScrollingView") { (coordinator) in
    coordinator.present(ScrollingViewController())
}

DebugController.open(completionHandler: nil)

---

UIKit Reimplementations

PerformLabel

A faster label useful for auto sizing cells. Animates smoothly by streching. Even though a numberOfLines API is defined, the current implementation will disregard this setting.

Code Sample

lazy var contentLabel: PerformLabel = {
    return PerformLabel()
        .align(.left)
        .color(.background, .black)
        .color(.text, .white)
        .size(.body)
}()

---

UI Components

CountdownPickerView

Display a countdown picker with seconds that is very close to the native iOS Timer app. All labels will be translated automatically depending on the phone's locale. A maximum width prevents this view from overflowing.

First Steps

Create a new CountdownPickerView instance and add it to a target view.

Code Sample

let datePicker = CountdownPickerView()
datePicker.isEndless = true
datePicker.countDownDuration = TimeInterval(3 * 60 * 60 + 2 * 60 + 1)
view.addSubview(datePicker)

---

NotificationView

Display a short message with an icon to inform about a success or error case. The message will dismiss itself after a certain duration or with a swipe.

Important Notes

Only show short messages. A message with a required width less than the width of the superview's frame will only take up the minimum required space.

Code Sample

NotificationView.show(.success, in: self.navigationController?.view, for: 2, message: "Document Uploaded")

---

ProgressView

Able to display a progress spinner in different styles to indicate a loading state. Blocks interaction of the underlying UI when visible.

First Steps

Use the convenience method showProgressView() on any UIView to display a loading state.

Code Sample

view.showProgressView(true, type: .appleStyle)
DispatchQueue.main.asyncAfter(deadline: .now() + 5) {
    view.showProgressView(false)
}

---

SheetView

Display a customisable sheet similar to UIAlertController.Style.actionSheet, that is both more flexible and easier to use.

Structure

A SheetView instance can be constructed using components. A component provides a contentView and a given height (height can either be static or dynamic, use invalidateLayout() to recalculate). Premade SheetViewComponent include:

   - SheetViewPullTab: A pill view indicating that the sheet can be interactively dismissed  
   - SheetViewNavigationBar: A simple compact `UINavigationBar` replica   
   - SheetViewButton: A button module that highlights and acts like an UIAlertController button   
   - SheetViewSeparator: A hairline divider used to separate components   
   - SheetViewSpace: Divides components into sections   
   - SheetViewCustomView: A base class to use for adding custom UI to SheetView   

Each section (divided by SheetViewSpace), has a background which can be styled using sectionBackgroundViewProvider(). To further style the sheet, use maximumWidth, adjustToSafeAreaInsets or horizontalInset. After components have been added and the sheet is styled, display it using show(in view: UIView?).

Code Sample

let sheetView = SheetView()
 sheetView.components = [
    SheetViewButton("Delete", configurationHandler: { (button) in
        button.color(.text, .red)
    }, onTap: nil),
    SheetViewSpace(),
    SheetViewButton("Cancel", onTap: nil),
 ]
 sheetView.show(in: self.view)

---

Common

DispatchQueue Extension

Reintroduces dispatchOnce with a twist. On subsequent invokations an optional else closure can be called. Adds a concise asyncAfter method.

Code Sample

DispatchQueue.main.once {
    print("Called only one time")
} else: {
    print("Called subsequently")
}

DispatchQueue.main.async(after: 1.0) {
    print("1s later")
}

String Extension

Adds file path conveniences to Swift's String.

Code Sample

"/Users/me/document.pdf".lastPathComponent
"/Users/me/document.pdf".pathExtension

NotificationCenter Extension

Receive a Notification by adding observe to a subclass of NSObject, which either accepts a raw String or a Notification.Name object. If you don't capture self strongly, the closure will deregister itself when the parent object is released. Post a Notification by calling emit().

Code Sample

observe("hi") { (notification) in
    print("Hi observed")
}

emit("hi")

Reasoning

1. BaseComponents allows you to write efficient & understandable code in a short amount of time by abstracting the tedious stuff. Implementing data sources or delegates takes a lot of boilerplate and often there's no need. Closures provide us with the ability to mentally connect the component with an action and is therefore the preferred way of passing values async in this library.

2. BaseComponents is flexible, meaning that you don't always have to use the components that come with it. Everything is built on top of UIKit, so mix and match if the project requires it. Don't be afraid of using UITableView instead of DataRender if you need the flexibility of tweaking every single value.

3. BaseComponents is evolving. Like Swift, this library will evolve over time to account for new improvements in the language and to cover more features. Documentation will improve and so will the understanding of what is needed next. SwiftUI is on the horizon as the next big thing, but in the mean time, I'm sure that UIKit will stick around. Particularly due to stability and predictability across iOS versions.

Sample Code

When looking at the sample code, we have a View Controller that supports:

• Dynamic Type
• Self-sizing cells
• Refresh control, reloading the data
• Layout fully in code
• Minimal state
• Easily understandable components
• Fetching JSON data and binding it to a model
• Responding to size of Keyboard

Check out the complete code for the screenshot here or others in the wiki.

Documentation

Documentation on the components is improving and pull requests are always welcome.