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Apple’s iOS 26 introduces a new visual style with the glassEffect modifier in SwiftUI, enabling developers to apply a translucent, glass-like appearance to views. This article explains how to use the glassEffect modifier, clarifies the role of the interactive parameter, and provides a method to maintain compatibility with earlier iOS versions.

Applying the Glass Effect

The glassEffect modifier, available in iOS 26 and later, applies a glass-like material to a SwiftUI view. It requires a shape parameter to define the area where the effect is applied and an optional style parameter to specify the material’s appearance. The modifier can also enable interactivity, allowing the effect to respond to user interactions.

Here’s an example of how to implement the glassEffect modifier:

import SwiftUI

struct ContentView: View {
    var body: some View {
        VStack {
            Text("Sample Text")
                .padding()
                .glassEffect(.regular.interactive(), in: .circle)
            Spacer()
        }
        .padding()
    }
}

In this code, the glassEffect is applied to a Text view within a Circle shape, with the .regular.interactive() style to enable dynamic behavior. The effect creates a translucent background that adapts to the content behind it, providing a modern aesthetic.

Understanding the Interactive Parameter

The interactive parameter, used with the glassEffect modifier, enables the glass material to dynamically respond to user interactions. The .interactive() style adjusts the appearance of the glass effect in real-time based on user input, creating a more engaging and responsive visual experience. For example, the effect may subtly shift or blur as the user interacts with the view, enhancing the perception of depth and materiality. When interactive is false or omitted, the glass effect remains static, maintaining a consistent appearance regardless of user actions.

Ensuring Backward Compatibility

To support devices running iOS versions earlier than 26, developers can create a custom view modifier that conditionally applies the glassEffect or a fallback implementation. The fallback can use existing SwiftUI materials, such as .ultraThinMaterial, combined with gradients and strokes to approximate the glass effect. Note that the provided fallback implementation example does not support interactivity.

Below is an implementation of a custom view modifier and a shape extension to achieve this:

import SwiftUI

extension View {
    @ViewBuilder
    func glassedEffect(in shape: some Shape, interactive: Bool = false) -> some View {
        if #available(iOS 26.0, *) {
            self.glassEffect(interactive ? .regular.interactive() : .regular, in: shape)
        } else {
            self.background {
                shape.glassed()
            }
        }
    }
}

extension Shape {
    func glassed() -> some View {
        self
            .fill(.ultraThinMaterial)
            .fill(
                .linearGradient(
                    colors: [
                        .primary.opacity(0.08),
                        .primary.opacity(0.05),
                        .primary.opacity(0.01),
                        .clear,
                        .clear,
                        .clear
                    ],
                    startPoint: .topLeading,
                    endPoint: .bottomTrailing
                )
            )
            .stroke(.primary.opacity(0.2), lineWidth: 0.7)
    }
}

The glassedEffect modifier checks the iOS version using #available. For iOS 26 and later, it applies the native glassEffect modifier, with an option for interactivity. For earlier versions, it falls back to a custom glassed shape modifier that combines .ultraThinMaterial with a linear gradient and a subtle stroke to mimic the glass-like appearance.

Usage Example

To apply the custom modifier, use the following code:

import SwiftUI

struct ContentView: View {
    var body: some View {
        VStack {
            Text("Some text here")
                .padding()
                .glassedEffect(in: .capsule, interactive: true)
            Spacer()
        }
        .padding()
    }
}

#Preview {
    ContentView()
}

This example applies the glassedEffect to a Text view within a Capsule shape. The interactive parameter is set to true, enabling dynamic behavior on iOS 26 and above, while the fallback ensures a consistent visual style on older systems.

Conclusion

By using the provided custom modifier, developers can integrate the glass effect into their SwiftUI applications while maintaining compatibility across a range of iOS versions.