Altering Format with HStack and VStack


Ranging from iOS 16, SwiftUI offers AnyLayout and the Format protocol for builders to create personalized and complicated layouts. AnyLayout is a type-erased occasion of the structure protocol. You need to use AnyLayout to create a dynamic structure that responds to customers’ interactions or atmosphere modifications.

On this tutorial, you’ll discover ways to use AnyLayout to change between vertical and horizontal structure.

Utilizing AnyLayout

Let’s first create a brand new Xcode challenge utilizing the App template. Title the challenge SwiftUIAnyLayout or no matter title you like. What we’re going to construct is an easy demo app that switches the UI structure while you faucet the stack view. The determine under exhibits the UI structure for various orientations.

SwiftUI AnyLayout - Switch between HStack and VStack

The app initially arranges three pictures vertically utilizing VStack. When a consumer faucets the stack view, it modifications to a horizontal stack. With AnyLayout, you possibly can implement the structure like this:

We outline a structure variable to carry an occasion of AnyLayout. Relying on the worth of changeLayout, this structure modifications between horizontal and vertical layouts. The HStackLayout (or VStackLayout) behaves like a HStack (or VStack) however conforms to the Format protocol so you should use it within the conditional layouts.

By attaching the animation to the structure, the structure change may be animated. Now while you faucet the stack view, it switches between vertical and horizontal layouts.

Switching Layouts primarily based on the machine’s orientation

At the moment, the app lets customers change the structure by tapping the stack view. In some functions, you might wish to change the structure primarily based on the machine’s orientation and display screen dimension. On this case, you possibly can seize the orientation change by utilizing the .horizontalSizeClass variable:

And you then replace the structure variable like this:

Say, for instance, you rotate an iPhone 14 Professional Max to panorama, the structure modifications to horizontally stack view.

swiftui anylayout demo

Typically, we use SwiftUI’s built-in structure containers like HStackLayout and VStackLayout to compose layouts. What if these structure containers aren’t adequate for arranging the kind of layouts you want? The Format protocol launched in iOS 16 means that you can outline your individual customized structure. All you have to do is outline a customized structure container by creating a sort that conforms to the Format protocol and implementing its required strategies:

  • sizeThatFits(proposal:subviews:cache:) – reviews the dimensions of the composite structure view.
  • placeSubviews(in:proposal:subviews:cache:) – assigns positions to the container’s subviews.

Abstract

The introduction of AnyLayout permits us to customise and alter the UI structure with a pair traces of code. This undoubtedly helps us construct extra elegant and interesting UIs. Within the earlier demo, I confirmed you the right way to swap layouts primarily based on the display screen orientation. In truth, you possibly can apply the identical approach to different situations like the dimensions of the Dynamic Kind.

Be aware: If you wish to dive deeper into SwiftUI and entry all of the supply code, you possibly can take a look at our Mastering SwiftUI ebook, which has been absolutely up to date for iOS 16 and Xcode 14.


Founding father of AppCoda. Creator of a number of iOS programming books together with Starting iOS Programming with Swift and Mastering SwiftUI. iOS App Developer and Blogger. Observe me at Fb, Twitter and Google+.



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