Sample project for testing out focus in SwiftUI and iOS 15

This project was to test out different ways of enabling focus in a SwiftUI app. Specifically I wanted to figure out how to force focus on newly created TextFields so that when they were added focus was set on them.

The secondary objective was to enable a user to click a button next to an existing text field and return focus to that particular field. The key was that the object backing each text field also had a UUID associated with the backing string. This UUID is what was being used to track which field got focus.

I looked at 5 ways of accomplishing this.

1. Custom @Environment of type UUID (ContentViewEnvironment.swift)
2. Custom @EnvironmentObject wrapping a published UUID (ContentViewEnvironmentObject.swift)
3. Passing a FocusState<UUID?>.Binding variable to each view (ContentViewVariablePassing.swift)
4. Custom @EnvironmentObejct wrapping a focus binding FocusState<UUID?>.Binding (ContentViewBindingEnvironmentObject.swift)
5. Custom @Environment of type FocusState<UUID?>.Binding (ContentViewBindingEnvironment.swift)

What I found is that: Solution #1 was able to set focus on each new TextField but was not able to change the focus based on the button click.

Solution #2 enabled both required features but required each TextField implement onAppear and onReceive for the solution to work correctly.

Solution #3 enabled both required features but required that each view store and pass the binding down to subviews even if that view didn't need the behaviors.

Solution #4 enabled both required features but did not have the detractions of #2 or #3.

Solution #5 I could not get working.