seek-stackable

iOS framework for laying out nested views vertically and horizontally.

• History
• Why use stackable?
• What it's not
• Current Limitations
• Example

History

We wanted to be able to layout variable height UITableViewCell's without paying a penalty in scrolling smoothness and without having to maintain frame layout code.

Why use stackable?

• It's just frames
• Get the performance of frame layout without lots of code
• Declarative view expression makes for easy integration in code
• Frames can be cached
• Frames are immutable
• Integration with various controls is extensible using protocol extensions
• Interfaces with standard UIKit controls
• Currently used by the SEEK iOS App for Search Results

What it's not

• stackable is not a replacement for UIStackView
  • stackable is not meant to be dynamic like UIStackView, relying on immutable frames instead
  • Currently a number of features in UIStackView are not available in stackable such as alignment options but this will change over time
• stackable is not based on AutoLayout
  • AutoLayout is powerful but difficult to tune for performance

Current Limitations

• integration has only been verified with UILabel and UIImageView
• no alignment options
• no distribution options

Example

let descriptionLabel = UILabel()
let attribute1 = UILabel()
let attribute2 = UILabel()
let attribute3 = UILabel()
let logoImageView = UIImageView()

let stack = VStack(spacing: 2) {[
  HStack(spacing: 10) {[
    VStack(spacing: 1) {[
      attribute1,
      attribute2,
      attribute3
    ]},
    logoImageView.stackSize(100, 100)
  ]},
  descriptionLabel
]}

let width = self.frame.size.width

// give me the frames
let stackedFrames = stack.framesForLayout(width)

// how tall is the stack?
let height = stack.heightForFrames(stackedFrames)

// lay the frames out
stack.layoutWithFrames(stackedFrames)