There are some useful things that I could do with Autolayout that still seem near impossible with SwiftUI.
For some of these trickier situations, I've seen example code (not from Apple) that uses SwiftUI's "preferences" plus GeometryReader to achieve something like a constraint. But the code is very ugly (in my opinion), and it sometimes logs runtime warning messages about changing state during layout. And I've never seen anyone from Apple say "yes, that's how we imagined you using that preferences API". So it seems like a hack.
Examples of things that are easy in Autolayout but have no obvious equivalent in SwiftUI, that I know of:
1. Aligning elements in different branches of view tree
For example, a form-like layout with labels and editable fields. You want to say "make the labels equal width, or trailing-aligned". Each row might be in a HStack. If you make each column a VStack, you have the same problem in the vertical direction, if some of your right-side fields are different heights.
This is the kind of thing I've seen hacked with "preferences".
2. Center a label but slide it if needed
Maybe that's a header at the top of the screen. Imagine for some some languages or font preference, the left side text grows. You'd want to slide the center text over. That's easy with autolayout and constraint priorities. I have no clue how to do it with SwiftUI.
Those are two examples I can remember. Maybe people can post more.
I'd love to know what Apple's SwiftUI devs think of that Preferences quasi-constraint hack, or if people have nice solutions to the examples above.
For some of these trickier situations, I've seen example code (not from Apple) that uses SwiftUI's "preferences" plus GeometryReader to achieve something like a constraint. But the code is very ugly (in my opinion), and it sometimes logs runtime warning messages about changing state during layout. And I've never seen anyone from Apple say "yes, that's how we imagined you using that preferences API". So it seems like a hack.
Examples of things that are easy in Autolayout but have no obvious equivalent in SwiftUI, that I know of:
1. Aligning elements in different branches of view tree
For example, a form-like layout with labels and editable fields. You want to say "make the labels equal width, or trailing-aligned". Each row might be in a HStack. If you make each column a VStack, you have the same problem in the vertical direction, if some of your right-side fields are different heights.
Code Block Name: [ text field ] Favorite color: [ text field ] Description: [ text area ] [ ] Enabled: [checkbox]
This is the kind of thing I've seen hacked with "preferences".
2. Center a label but slide it if needed
Code Block | Left text Center text |
Maybe that's a header at the top of the screen. Imagine for some some languages or font preference, the left side text grows. You'd want to slide the center text over. That's easy with autolayout and constraint priorities. I have no clue how to do it with SwiftUI.
Code Block | Long Russian left text Center text |
Those are two examples I can remember. Maybe people can post more.
I'd love to know what Apple's SwiftUI devs think of that Preferences quasi-constraint hack, or if people have nice solutions to the examples above.