Understanding GeometryReader in SwiftUI

A Guide to Responsive and Adaptive Layouts in SwiftUI

Introduction

SwiftUI provides various tools for building dynamic and responsive user interfaces. One such powerful yet often overlooked tool is GeometryReader. It allows developers to obtain information about a view’s size and position, making it particularly useful for building adaptive layouts.

This article explores GeometryReader, its usage, and practical examples to help you understand how to leverage it in SwiftUI.

What is GeometryReader?

GeometryReader is a SwiftUI container view that provides access to its parent’s size and coordinate space. It allows developers to create views that dynamically adjust based on available space. When placed inside a layout, GeometryReader fills all available space and provides its child views with layout information via a GeometryProxy.

Syntax

GeometryReader { geometry in
    Text("Width: \(geometry.size.width), Height: \(geometry.size.height)")
}

Here, geometry is a GeometryProxy instance that contains size and coordinate information of the parent view.

Understanding GeometryProxy