GSKStretchyHeaderView

TableView

October 15, 2023

GSKStretchyHeaderView is an implementation of the stretchy header paradigm as seen on many apps, like Twitter, Spotify or airbnb. It’s designed in order to accomplish the following requirements:

Compatibility with UITableView and UICollectionView
Data source and delegate independency: can be added to an existing view controller withouth interfering with your existing delegate or dataSource
Provide support for frame layout, auto layout and Interface Builder .xib files
No need to subclass a custom view controller or to use a custom UICollectionViewLayout
Simple usage: just implement your own subclass and add it to your UIScrollView subclass
Two expansion modes: the header view can grow only when the top of the scroll view is reached, or as soon as the user scrolls down.

If you are using this library in your project, I would be more than glad to know about it!

Usage

To add a stretchy header to your table or collection view, you just have to do this:


                                              
                                                var stretchyHeader: GSKStretchyHeaderViewSubclass!
…
func viewDidLoad() {

super.viewDidLoad()

let headerSize = CGSize(width: self.tableView.frame.size.width,

height: 200) // 200 will be the default height

self.stretchyHeader = GSKStretchyHeaderViewSubclass(frame: CGRect(x: 0, y: 0,

width: headerSize.width,

height: headerSize.height))

self.stretchyHeader.delegate = self // this is completely optional

self.tableView.addSubview(self.stretchyHeader)

}


                                              
                                                func viewDidLoad() {

super.viewDidLoad()

let nibViews = Bundle.main.loadNibNamed(“GSKTabsStretchyHeaderView”, owner: self, options: nil)

self.stretchyHeaderView = nibViews.firstObject

self.tableView.addSubview(self.stretchyHeaderView)

}

Compatibility with iOS 11 and the iPhone X

After the changes introduced in iOS 11, some issues have appeared with the safe area adjustments to scroll views. To avoid glitches and strange behaviours, just do the following when you set up your header view:


                                              
                                                if #available(iOS 11.0, *) {

self.tableView.contentInsetAdjustmentBehavior = .never

}

For the time being, we haven’t found a better way to deal with the contentInset adjustment, so the support for the iPhone X and the safeAreaInsets is not there yet. This may require a major refactor of the header view and a major release. For more information, see this issue and this PR (#68).

Configuration

You can change multiple parameters in your stretchy header view:


                                              
                                                // you can change wether it expands at the top or as soon as you scroll down

headerView.expansionMode = .immediate
// You can change the minimum and maximum content heights

headerView.minimumContentHeight = 64 // you can replace the navigation bar with a stretchy header view

headerView.maximumContentHeight = 280
// You can specify if the content expands when the table view bounces, and if it shrinks if contentView.height < maximumContentHeight. This is specially convenient if you use auto layout inside the stretchy header view

headerView.contentShrinks = true

headerView.contentExpands = false // useful if you want to display the refreshControl below the header view
// You can specify wether the content view sticks to the top or the bottom of the header view if one of the previous properties is set to `false`

// In this case, when the user bounces the scrollView, the content will keep its height and will stick to the bottom of the header view

headerView.contentAnchor = .bottom

Creating your stretchy header

There are two ways to create your own stretchy header:

Create a stretchy header subclass and add subviews to its contentView. You can layout its subviews manipulating their frames or using Auto Layout (also works with GranadaLayout ).
Create an Interface Builder file and map it to your GSKStretchyHeaderView subclass. Subviews added to the stretchy header will be automatically moved to the content view, keeping their constraints. Remember to set the properties maximumContentHeight and minimumContentHeight in the attributes inspector (fourth tab on the right panel in Interface Builder).

To modify the behaviour and layout of your stretchy header, just override the method -didChangeStretchFactor: in your subclass, where you can adjust it by using the stretchFactor. To get a more detailed description of the properties, please have a look at the source code. There are also a few usage examples in the example project. You can also take them as a reference for your own stretchy headers.

Example project

To run the example project, clone the repo and open the workspace file GSKStretchyHeaderView.xcworkspace.

You can also use pod try GSKStretchyHeaderView.

Installation

GSKStretchyHeaderView is available through CocoaPods. To install it, simply add the following line to your Podfile, you can check the Example Podfile to see how it looks like:


                                              
                                                pod “GSKStretchyHeaderView”

GSKStretchyHeaderView is also available through Carthage. To install it, just add this line to your `Cartfile:


                                              
                                                github “gskbyte/GSKStretchyHeaderView”

and run


                                              
                                                carthage update GSKStretchyHeaderView

GitHub

View Github

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