Stevia

:leaves: Concise Autolayout code

freshOS

3382

214

Swift

Winner of Hacking with Swift Recommended award

You + Stevia = 🦄

[x] 💡 Write concise, readable layouts
[x] 🏖 Reduce your maintenance time
[x] 🎨 Compose your styles, CSS-like
[x] 🔴 Plug Live reload and boost your iteration cycles

Reason - Example - Live Reload - Installation - Documentation

🖼 Visual Layout Api

layout {
    100
    |-email-| ~ 80
    10%
    |-password-forgot-| ~ 80
    >=20
    |login| ~ 80
    0
}

⛓ Chainable Api

email.top(100).left(8).right(8).width(200).height(44)
alignHorizontally(password, forgot)
image.fillContainer()
button.centerInContainer().size(50%)
equalWidths(email, password)
image.width(>=80)

📐 Equation-Based Api

email.Top == 100
password.CenterY == forgot.CenterY
login.Top >= password.Bottom + 20
login.Width == 75 % Width
(image.Height == 100).priority = UILayoutPriority(rawValue: 999)

All Generate native NSLayoutConstraints 🎉

👨‍🔬Try it!

Stevia is part of freshOS iOS toolset. Try it in an example App ! Download Starter Project

💡 Reason

Because nothing holds more truth than pure code 🤓
Xibs and storyboards are heavy, hard to maintain, hard to merge.
They split the view concept into 2 separate files making debugging a nightmare
There must be a better way

How

By creating a tool that makes Auto layout code finally readable by a human being.
By coupling it with live code injection such as injectionForXcode we can design views in real time
View layout becomes fun, concise, maintainable and dare I say, beautiful ❤️

Login View Example

In the project folder, you can find an example of a typical login view laid out in both native and Stevia for you to understand and compare the two approaches.

As a spoiler alert, the number of characters goes from 2380 to 1239 ( ~ divided by 2)

Write Half the code that is actually 10X more expressive and maintainable !

🔴 Live Reload

Live reload enables you to develop your views live without relaunching the app everytime.

Stevia + InjectionForXcode = #WhoNeedsReactNative?? 🚀

Just Cmd+S and you can dev live in the simulator !

Learn more about how to set up live reload here.

⚙️ Installation

Stevia is installed via the official Swift Package Manager.

Select Xcode>File> Swift Packages>Add Package Dependency...
and add https://github.com/freshOS/Stevia.

The Swift Package Manager (SPM) is now the official way to install stevia. The other package managers are now deprecated as of 4.8.0 and won’t be supported in future versions.
For Carthage/Cocoapods support (legacy versions) see documentation here.

📖 Documentation

The following will teach you the gist of Stevia in one minute.
To go further, you can refer to the full documentation here.

Stevia enables you to write readable Auto Layout code. It does so by tackling the 3 main components of layout: view hierarchy, layout and styling.

01 - View hierarchy

email.translatesAutoresizingMaskIntoConstraints = false
password.translatesAutoresizingMaskIntoConstraints = false
login.translatesAutoresizingMaskIntoConstraints = false
addSubview(email)
addSubview(password)
addSubview(login)

becomes

subviews {
    email
    password
    login
}

02 - Layout

email.topAnchor.constraint(equalTo: topAnchor, constant: 100).isActive = true
email.leftAnchor.constraint(equalTo: leftAnchor, constant: 8).isActive = true
email.rightAnchor.constraint(equalTo: rightAnchor, constant: -8).isActive = true
email.heightAnchor.constraint(equalToConstant: 80).isActive = true

password.topAnchor.constraint(equalTo: email.bottomAnchor, constant: 8).isActive = true
password.leftAnchor.constraint(equalTo: leftAnchor, constant: 8).isActive = true
password.rightAnchor.constraint(equalTo: rightAnchor, constant: -8).isActive = true
password.heightAnchor.constraint(equalToConstant: 80).isActive = true

login.topAnchor.constraint(lessThanOrEqualTo: password.bottomAnchor, constant: 20).isActive = true
login.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
login.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
login.heightAnchor.constraint(equalToConstant: 80).isActive = true
login.bottomAnchor.constraint(equalTo: bottomAnchor, constant: 0).isActive = true

becomes

layout {
    100
    |-email-| ~ 80
    8
    |-password-| ~ 80
    >=20
    |login| ~ 80
    0
}

03 - Styling

email.borderStyle = .roundedRect
email.autocorrectionType = .no
email.keyboardType = .emailAddress
email.font = UIFont(name: "HelveticaNeue-Light", size: 26)

becomes

email.style { f in
    f.borderStyle = .roundedRect
    f.autocorrectionType = .no
    f.keyboardType = .emailAddress
    f.font = UIFont(name: "HelveticaNeue-Light", size: 26)
    f.returnKeyType = .next
}