TZStackView

A wonderful layout component called the UIStackView was introduced with iOS 9. With this component it is really easy to layout components in a row both horizontally and vertically. Apple recommends using the UIStackView wherever possible and resort to explicit NSLayoutConstraints only when there is no way to do it with UIStackView. This saves you lots of boiler plate NSLayoutConstraint creation code.

UIStackView requires iOS 9, but we're not ready to make our apps require iOS 9+ just yet. In the meanwhile, we developers are eager to try this component in our apps right now! This is why I created this replica of the UIStackView, called the TZStackView (TZ = Tom van Zummeren, my initials). I created this component very carefully, tested every single corner case and matched the results against the real UIStackView with automated XCTestCases.

Features

• ✅ Compatible with iOS 7.x and iOS 8.x
• ✅ Supports the complete API of UIStackView including all distribution and alignment options
• ✅ Supports animating the hidden property of the arranged subviews
• ❌ Supports Storyboard

So this implementation does not support Storyboard. It is meant for iOS developers who, like me, want to use the UIStackView in our existing apps and like to layout their components in code as opposed to using Storyboard.

Setup

You basically have two options to include the TZStackView in your Xcode project:

Use Cocoapods

Example Podfile:

source 'https://github.com/CocoaPods/Specs.git'
platform :ios, "8.0"
use_frameworks!

pod "TZStackView", "1.1.0"

Unfortunately, using Cocoapods with a Swift pod requires iOS 8.

Drag files directly into your project

Alternatively (when you do want to support iOS 7) drag in the following classes from the Example folder directly into your Xcode project

• TZStackView
• TZSpacerView
• TZStackViewAlignment
• TZStackViewDistribution

Example usage

Given view1, view2 and view3 who have intrinsic content sizes set to 100x100, 80x80 and 60x60 respectively.

let stackView = TZStackView(arrangedSubviews: [view1, view2, view3])
stackView.distribution = .FillEqually
stackView.alignment = .Center
stackView.axis = .Vertical
stackView.spacing = 25

This would produce the following layout:

See the developer documentation for UIStackView for all other combinatins of distributions, alignments and axis. TZStackView works and behaves exactly the same way as the UIStackView except for not supporting Storyboard. If you do find a case where it does not behave the same way, please file a bug report.

To animate adding a view to or removing a view from the arranged subviews, simply hide or show them by adjusting the hidden property within an animation block (as described by the UIStackView reference docs as well):

UIView.animateWithDuration(0.5, animations: {
	self.view2.hidden = true
})

Migrating to UIStackView

If at a later point you decide to make iOS 9 the minimum requirement of your app (it will happen sooner or later), you will want to migrate to the real UIStackView instead of using this implementation. Because the TZStackView is a drop-in replacement for UIStackView, you simply replace:

let stackView = TZStackView(arrangedSubviews: views)

with ...

let stackView = UIStackView(arrangedSubviews: views)

... and you're good to go! You will not need to make any other changes and everything will simply work the way it worked before.

License

TZStackView is released under the MIT license. See LICENSE for details.