SwiftUI-Inspect

Inspect is a new approach at accessing UIKit and AppKit components from within SwiftUI more safely and swifty. It is heavily inspired by SwiftUI-Introspect, but does not use any of the old code.

Coverage

SwiftUI	UIKit	AppKit	Notes
TextField	UITextField	NSTextField
TextEditor	UITextEditor	NSTextView
ScrollView	UIScrollView	NSScrollView
List/Form	ListInspectionNativeView*	NSTableView
any View	ListCellInspectionNativeView*	not implemented yet	This can be called on any view that represents a List or Form Cell. The function is called inspectListOrFormCell.
Button	is no native control	NSButton
Toggle	UISwitch	NSButton
Slider	UISlider	NSSlider
Stepper	UIStepper	NSStepper
DatePicker	UIDatePicker	NSDatePicker
Picker	UISegmentedControl	NSSegmentedControl	This currently only supports the PickerStyle.segmentedControl right now, which is why the method is called inspectSegmentedControl.
ColorPicker	UIColorWell	NSColorWell
NavigationView / NavigationStack	UINavigationController / UISplitViewController / UINavigationBar	is no relevant native control	The default function inspect returns a UINavigationController. UISplitViewController is available via inspectSplitViewController and UINavigationBar using inspectNavigationBar.
TabView	UITabBarController / UITabBar	is no relevant native control	The default function inspect returns a UITabBarController. UITabBar is available via inspectTabBar.

*on iOS, depending on the environment and OS Version, List and Form can be both a UITableView and a UICollectionView and thus their subviews can be either UITableViewCell or UICollectionViewCell. ListInspectionNativeView and ListCellInspectionNativeView are enums, which contain the found view as an associated value (e.g. ListInspectionNativeView.tableView(UITableView)). In most instances you should propably support both cases.

Why it is more safe and more swifty than Introspect

The biggest differences between Inspect and Introspect are:

1. Inspect does not assume a strict view hierarchy (for example for the searched view to be a child of the parent of the InspectionView), but instead goes through the levels of the view hierarchy until it has found the correct view. It does so by matching the InspectionView frame against the frame of any potential result candidate.
2. By searching for the view with the correct frame, some problems we encountered with Introspect can be avoided, for example when adding multiple views of the same type to a VStack or HStack and inspecting one of them, Inspect will retrieve the right one, while Introspect often retrieved the first one.
3. Inspects public API heavily embraces Swifts strong type system. You can only call inspect on the SwiftUI type that corresponds to the searched-for UIKit or AppKit type. For example, on iOS, you call inspect() on a SwiftUI TextField and get a UITextField. You cannot call inspect() to retrieve a UITextField on any other SwiftUI type, not even on a modified TextField. This does not apply to UITableViewCell resp. UICollectionViewCell, which do not have a corresponding SwiftUI type.

How it works

Inspect works by adding a InspectionView, as a background view, to the view hierarchy. It then looks for a view that has the same global frame as the InspectionView and is of the type you are looking for. It is a little bit more complicated in some cases, where the looked-for frame differs from the InspectionView‘s frame, but you can find all of that out by looking at the code.

Please note that this introspection method might break in future SwiftUI releases. Future implementations might not use UIKit elements that are being looked for. Though the library is unlikely to crash, the .inspect() method will not be called in those cases.

Usage in production

Inspect can be used in production and follows some ground-rules to operate:

• Inspect will never use private APIs
• Inspect will never force-cast to the UIKit or AppKit counterparts

Examples

TextField

TextField("Placeholder", text: $textValue)
.inspect { field in
    field.layer.backgroundColor = UIColor.red.cgColor
}

Install

SwiftPM

https://github.com/quintschaf/SwiftUI-Inspect.git

To-Do

• Efficiency Improvements
• Assert and support more views
• Add more examples to the readme
• Add more documentation
• Support tvOS
• Support more Picker styles other than .segmentedControl, propably with an enum return (like a List)

Special Thanks

Special thanks to Siteline, Loïs Di Qual and all other contributors of SwiftUI-Introspect for a lot of inspiration.