Customizing the navigation bar appearance

• iOS is opinionated about navigation bars, but we can make some adjustments
• basically color, visibility, and which modifiers affect which toolbars (of which there are several types)

Placing toolbar buttons in exact locations

• iOS will put toolbar buttons on the trailing edge of the toolbar by default
• you can specify the placement of a ToolbarItem
  • based on position e.g. ToolbarItem(placement: .topBarLeading)
  • or function ToolbarItem(placement: .confirmationAction)
• you can group toolbar items using ToolbarItemGroup

Making your navigation title editable

• .inline style navigation titles can be attached to a binding variable which we can access

Programmatic navigation with NavigationStack

• “programmatic navigation” to switch views based solely on code, not on the user doing something in particular
• bind a path variable to the NavigationStack (as an array)
• call the path in code, including any subpaths
• use the modifier navigationDestination()

You can put the view in the initiator (in this example, a button) and it doesn’t need to be added to the array before using it. I imagine you create the array so you can save state later.

I tried to replace the Int array with a String array but wasn’t entirely successful in doing it without typing the strings in e.g. path = ["string 1", "string 2"]

Navigating to different data types using NavigationPath

• this is for mixed-types of navigation views
• you don’t need the array unless you intend to keep the path(s)
• since you might have, say, Strings and Ints in your path, you need to use a special SwiftUI type called NavigationPath
• NavigationPath uses “type erasure” which means it will store different types of items as long as they are Hashable
• I wonder what Representation.eager means? (It’s internal. It has a .lazy counterpart)

You selected the string Hello
Path = NavigationPath_items:
SwiftUl.NavigationPath.(unknown context at $1d36ffa00).Representation.eager([CodableltemBox (Hello)]), subsequentitems: [l, iterationindex: O)

• unlike the standard array used in the first example (where you could just say path = [56]), you can’t easily talk to the NavigationPath() object.

Cannot assign value of type ‘String’ to type ‘NavigationPath’

How to make a NavigationStack return to its root view programmatically

• too many back buttons? Reset the path to go home > @Binding property wrapper lets us pass an @State property into another view and modify it from there – we can share an @State property in several places, and changing it in one place will change it everywhere.

How to save NavigationStack paths using Codable

• can be done with either the array-style path object or the NavigationPath object
• using JSONEncode... etc.
• since NavigationPath doesn’t need to have Codable objects (only Hashable), need to check that you can decode it first.

This is all very theoretical. I can understand why you would be doing this, but the “sandbox” code he’s using to demonstrate it doesn’t really help me understand how I would use it in an app.

Resizing images to fit the available space

As anyone who has dealt with trying to make images fit proportionally to an area (HTML I’m looking at you), it’s never as easy as saying “here’s an image, here’s a space, make it happen.”

And SwiftUI does it with a boatload of modifiers

Image(.example)
    .resizable().    // can be resized
    .scaledToFit().  // don't squish the image
    .containerRelativeFrame(.horizontal) { size, axis in
        size * 0.8   // use 80% of the available width
    }

I’ve been wondering about relative width!

How ScrollView lets us work with scrolling data

• use ScrollView { … } instead of say, List
• when views are added to a scroll view they are immediately created (whether you can see them or not)
• consider using LazyVStack (or the H equivalent)
• lazy stacks take up all available space, as opposed to regular stacks that take up only what they need

Pushing new views onto the stack using NavigationLink

• View stacks a fundamental way of working with iOS
• different from sheets because of how the information is presented
• a NavStack with NavigationLink destination (which can be any view)
• use for details about the current selection
• sheet is for unrelated content

Working with hierarchical Codable data

• for example, an array inside another array, with different data types
• used in conjunction with JSON, will go as far down as the data does (as long as it’s valid JSON of course)

How to lay out views in a scrolling grid

• good for showing columns of information
• LazyVGrid to show vertical data; LazyHGrid for horizontal
• can use adaptive modifier to use up available space rather than specifying the exact number of columns, e.g. let layout = [ GridItem(.adaptive(minimum: 80, maximum: 120)), ]