How do you use animations in SwiftUI?

When using SwiftUI, you can individually animate changes to views, or to a view’s state, no matter where the effects are. SwiftUI handles all the complexity of these combined, overlapping, and interruptible animations for you.

Animations in SwiftUI are simple to create, and can range from subtle transitions to complex, multi-step animations. They can be used to provide feedback to users, draw attention to important elements, and add a sense of delight to your app. Animations in SwiftUI are also highly customizable, giving you fine-grained control over timing, easing, and more.

Using withAnimation global function

You can animate the value of a view’s properties, such as its position, opacity, or color, using the withAnimation(_:_:). For example, to animate a change in the position of a view, you can wrap the change inside the withAnimation block like this:

Button("Animate") {
    withAnimation {
        self.position = CGPoint(x: 100, y: 100)
    }
}

Transitions between views

You can add animations to the transition between two views, for example, when navigating from one view to another. You can do this by setting the transition(_:) modifier on the view, and specifying the type of animation you want to use, such as opacity, move, slide, and offset. For example:

NavigationLink(destination: DetailView()) {
    Text("Navigate")
}
.transition(.slide)

Implicit animations

SwiftUI provides implicit animations for some view properties, such as opacity and scaleEffect. You can animate these properties by simply changing their value, and SwiftUI will automatically animate the change. For example:

Image(systemName: "heart.fill")
    .foregroundColor(.red)
    .opacity(self.isLiked ? 1 : 0)

Using animation(_:value:) view modifier

There are many different types of animations you can use with the animation(_:value:) modifier, such as spring, linear, and easeInOut. You can also customize your animations even further by using other modifiers such as delay, repeatCount, and autoreverses.

// You can use the spring animation
Image(systemName: "heart.fill")
    .foregroundColor(.red)
    .scaleEffect(self.isLiked ? 1.2 : 1)
    .animation(.spring())

// You can use the easeInOut animation
Text("Hello, World!")
    .font(.largeTitle)
    .animation(.easeInOut)

// You can also specify the duration
Text("Hello, World!")
    .font(.largeTitle)
    .animation(.easeInOut, duration: 2)

// You can even chain multiple animations together
Text("Hello, World!")
    .font(.largeTitle)
    .animation(.easeInOut, duration: 2)
    .animation(.repeatForever(autoreverses: true))

Using binding’s animation(_:) method

SwiftUI’s Binding type allows you to create a two-way connection between a view and its underlying data. You can use the animation(_:) method in conjunction with a binding to animate changes to the bound data.

Toggle(isOn: $isOn.animation(.spring(response: 0.5, dampingFraction: 0.8))) {
    Text("Toggle")
}

Note that not all SwiftUI views support animations on their Bindings. Make sure to check the documentation of the view you are using to see if it supports animating changes to its Binding values.

Best practices

While animations can be a great addition to user interfaces, it is possible to use too much animation, which can actually detract from the user experience. If an app is overly animated, it can make the interface feel cluttered, overwhelming, and even confusing. In some cases, excessive animation can also slow down the app, making it feel sluggish and unresponsive.

It’s important to strike a balance between adding just the right amount of animation to your app, and avoiding an overload of animation that could negatively impact the user experience.

Animation should be used purposefully, to enhance the user experience, draw attention to important elements, and provide feedback on user interactions. In general, it’s best to keep animations simple and subtle, rather than flashy and over-the-top.

Some apps may require more animation than others, depending on their purpose and the preferences of their users. It’s also a good idea to test your animations with real users to get feedback on their effectiveness and adjust as necessary.