SwiftUI already streamlines the creation of view animations. One instance is the matchedGeometryEffect modifier, which allows builders to outline the looks of two views. The modifier calculates the disparities between the 2 views and robotically animates the dimensions and place adjustments. With iOS 17, Apple continues to enhance the SwiftUI framework and supply a brand new view known as PhaseAnimator, which permits us to construct extra refined animations.

On this tutorial, we are going to discover the capabilities of PhaseAnimator and learn to put it to use to create multi-step animations.

Constructing a Easy Animation with PhaseAnimator

The PhaseAnimator view, or the .phaseAnimator modifier, lets you generate multi-step animations. By biking by way of a set of phases that you simply present, every representing a definite step, you may create dynamic and interesting animations.

Let me give a easy instance, so you’ll perceive work the section animator. We’ll animate the transformation of a rounded rectangle. It begins as a blue rectangle, then scales up, adjustments shade to indigo, and incorporates a 3D rotation animation.

We are able to use the RoundedRectangle view to create the rounded rectangle and connect the phaseAnimator modifier to the rectangle like this:

Inside the section animator, we specify two phases: false and true. The view builder closure takes two parameters. The primary parameter is a proxy worth that represents the modified view. The second parameter signifies the present section.

When the view initially seems, the primary section (i.e. false) is lively. We set the size to 50% of the unique measurement and the foreground shade to blue. Within the second section, the rectangle scales again to its unique measurement and the colour transitions to indigo.

The section animator robotically animates the change between these two phases.

To create the 3D rotation animation, you may connect the rotation3DEffect modifier to the content material view like beneath:

If you wish to customise the animation, phaseAnimator additionally offers the animation parameter for outlining your most popular animation. Based mostly on the given section, you may specify the animation for use when transferring from one section to a different. Right here is an instance:

Utilizing Enum to Outline Multi Step Animations

Within the earlier instance, the animation consisted of solely two phases: false and true. Nonetheless, in additional complicated animations, there are sometimes a number of steps or phases concerned. On this case, an enum is an effective way to outline a listing of steps for the animation.

Let’s take into account an instance of animating an emoji icon with the next steps:

1. Initially, the emoji icon is centered on the display.
2. It scales up by 50% and rotates itself by 720 levels.
3. Subsequent, it strikes upward by 250 factors whereas concurrently cutting down by 20%.
4. Then, it strikes downward by 450 factors. Whereas descending, it rotates itself by 360 levels and scales down by 50%.
5. Lastly, it returns to its unique place.

With these steps, we are able to create a dynamic animation for the emoji icon.

To implement this multi-step animation, we are able to outline an enum like this:

On this enum, we have now 4 instances that symbolize completely different steps of the animation. Throughout every section, we carry out scaling, rotation, or motion on the emoji icon. To perform this, we outline three computed properties for every motion. Inside every property, we specify the values for the actual animation section or step.

As an example, within the “rotate” section, the emoji ought to be scaled up by 50% and rotated by 720 levels. The scale property returns 1.5, and the angle property returns Angle(levels: 720).

With the Section enum, we are able to now simply animate the emoji with the section animator like beneath:

The Section.allCases robotically informs the section animator in regards to the obtainable phases. Relying on the given section, the emoji icon is scaled, rotated, and moved in response to the computed values.

To customise the animation, we are able to specify a specific animation, comparable to snappy, for various phases as an alternative of utilizing the default animation.

Utilizing Triggers

At the moment, the section animator initiates the animation robotically and repeats it indefinitely. Nonetheless, there could also be conditions the place you like to set off the animation manually. In such instances, you may outline your standards by specifying the specified circumstances within the set off parameter of the section animator.

For instance, the emoji animation ought to be triggered when a consumer faucets on it. You possibly can first declare a state variable like this:

Subsequent, you replace the phaseAnimator modifier by including the set off parameter:

After making the code adjustments, the animation will solely be triggered when the worth of startAnimation is switched from false to true. To realize this, connect the onTapGesture modifier to the Textual content view.

When a consumer faucets the emoji, we toggle the worth of startAnimation. This triggers the multi-step animation.

Abstract

The introduction of PhaseAnimator has made the method of making multi-step animations extremely easy. By utilizing an enum to outline what adjustments ought to occur at every step of the animation, you may create dynamic and interesting animations with just some strains of code. SwiftUI’s PhaseAnimator, together with different useful options, takes care of the exhausting give you the results you want, so builders can give attention to making spectacular animations with none trouble.

Should you take pleasure in studying this tutorial, you may proceed to take a look at our Mastering SwiftUI guide to study extra in regards to the SwiftUI framework.