Traps and Countermeasures for Abnormal onAppear Calls in SwiftUI
onAppear is an extremely crucial lifecycle method in SwiftUI, used to inject key logic when a view is presented. Since view instances may be created and rebuilt frequently, developers often choose to prepare data and perform initialization operations within these methods. In theory, the timing of these lifecycle method calls should be predictable and consistent. However, in certain specific scenarios, onAppear may be called unexpectedly and unnecessarily. This not only can lead to performance overhead but also may cause uncontrollable changes in the application's state. This article will uncover this easily overlooked SwiftUI behavior trap and provide temporary countermeasures.
Intentional Design or Technical Flaw? The Anomaly of onChange in SwiftUI Multi-Layer Navigation
SwiftUI provides the onChange modifier, allowing developers to listen for changes in specific values within a view and execute corresponding actions when those values change. Intuitively, as long as a view is part of the currently visible branch of the view tree (active), the corresponding closure should be triggered when the observed value changes. However, in certain navigation scenarios, the onChange modifier seems to become "selectively deaf," inexplicably remaining silent even when the observed value changes. Is this a carefully designed feature by Apple, or a long-hidden code defect? This article aims to unveil this phenomenon and provide necessary caution to developers.
How to Tile Images in SwiftUI
Although image tiling is not a commonly used feature, most developers can easily master its implementation. A search engine query reveals that almost all results point to the same solution — using the `resizable` modifier. However, for a powerful UI framework, it is clearly not comprehensive to have only one solution for a requirement. In this article, we will explore two different implementations of image tiling and from there, introduce a less commonly used `Image` construction method in SwiftUI.
Common Misconceptions About SwiftUI
This article aims to explore several common misconceptions of SwiftUI to help developers better understand and utilize SwiftUI. We will dissect these misconceptions, including those about the perceived difficulty of learning SwiftUI, expectations of cross-platform development, the scope of framework capabilities, and misunderstandings about the amount of code involved. By clarifying these concepts, we hope to provide clearer learning directions and usage strategies for SwiftUI developers.
Developing an Infinite Four-Direction Scrollable Pager with SwiftUI
The advent of SwiftUI has brought revolutionary changes to Apple ecosystem development, but it still faces some challenges when addressing certain complex requirements. Recently, I developed a component called Infinite4Pager, which supports infinite four-direction scrollable paging. In this article, we will analyze the key ideas in the implementation process, discuss the points that need special attention, and candidly review the shortcomings of SwiftUI in coping with such scenarios. Through this case, we not only learn the specific technical implementation but also better understand how to break through the convention and solve problems creatively within the framework of SwiftUI.
Creating Stunning Dynamic Text Effects with TextRenderer
The Text component is extremely common in SwiftUI applications. Over the past few years, despite Apple continually expanding its capabilities, developers have been eager for deeper control over this component. At WWDC 2024, SwiftUI introduced the TextRenderer protocol, granting developers new powers to adjust the rendering performance of the Text component, making it possible to achieve many previously unimaginable effects. This article will delve into this new feature.
Mastering the containerRelativeFrame Modifier in SwiftUI
At the WWDC 2023, Apple introduced the containerRelativeFrame view modifier to SwiftUI. This modifier simplifies some layout operations that were previously difficult to achieve through conventional methods. This article will delve into the containerRelativeFrame modifier, covering its definition, layout rules, use cases, and relevant considerations. At the end of the article, we will also create a backward-compatible replica of containerRelativeFrame for older versions of SwiftUI, further enhancing our understanding of its functionalities.
The @State Specter: Analyzing a Bug in Multi-Window SwiftUI Applications
In this article, we will delve into a bug affecting SwiftUI applications in multi-window mode and propose effective temporary solutions. We will not only detail the manifestation of this issue but also share the entire process from discovery to diagnosis, and finally, resolution. Through this exploration, our aim is to offer guidance to developers facing similar challenges, helping them better navigate the complexities of SwiftUI development.
Practical SwiftData: Building SwiftUI Applications with Modern Approaches
In the previous article "Concurrent Programming in SwiftData", we delved into the innovative concurrent programming model proposed by SwiftData, including its principles, core operations, and related considerations. This elegant programming solution has earned considerable praise. However, as more developers attempt to use SwiftData in actual SwiftUI applications, they have encountered some challenges, especially after enabling Swift's strict concurrency checks. They found that SwiftData's actor-based concurrency model is difficult to integrate with traditional application construction methods. This article will explain, in a tutorial-like manner, how to integrate SwiftData with modern programming concepts smoothly into SwiftUI applications and provide strategies to address the current challenges faced by developers.
Exploring Property Wrappers in SwiftUI: @UIApplicationDelegateAdaptor, @AccessibilityFocusState, @FocusedObject, @FocusedValue, and @FocusedBinding
In this article, we will explore property wrappers such as @UIApplicationDelegateAdaptor, @AccessibilityFocusState, @FocusedObject, @FocusedValue, and @FocusedBinding. These property wrappers cover various functionalities including integration across different framework lifecycles, assistive focus, and management of focused value observations.
Exploring SwiftUI Property Wrappers: @AppStorage, @SceneStorage, @FocusState, @GestureState and @ScaledMetric
In this article, we will continue to explore property wrappers in SwiftUI @AppStorage, @SceneStorage, @FocusState, @GestureState, and @ScaledMetric. These property wrappers cover various aspects including data persistence, interactive response, accessibility features, and multi-window support, providing developers with succinct and practical solutions.
Mastering TipKit: Advanced
In the previous article, we introduced the basic usage of TipKit. In this article, we will discuss some advanced topics related to TipKit, such as how to fully customize Tip views (not using TipView and popoverTip), how to use TipKit with UIKit, and how TipKit can share data across different applications, as well as how to reuse Tip declaration code. Additionally, we will attempt to address some common questions and concerns about TipKit.
Mastering TipKit: Basics
TipKit is a framework introduced by Apple at WWDC 2023 that allows you to easily display tips in your applications. It can be used to introduce new features to users, help them discover hidden options, or demonstrate faster ways to accomplish tasks, among other scenarios. TipKit is compatible with different hardware environments and operating systems within the Apple ecosystem, including iPhone, iPad, Mac, Apple Watch, and Apple TV.
The Composable Architecture (TCA)
The Composable Architecture (TCA) is a SwiftUI framework that provides state and side effect management, testing and dependency injection. This article describes TCA's benefits, features, changes, learning, performance, and resources.
Creating Tables with Table in SwiftUI
Table is a table control provided for the macOS platform in SwiftUI 3.0, allowing developers to quickly create interactive multi-column tables. At WWDC 2022, Table was extended to the iPadOS platform, giving it a larger space to operate. This article will introduce the usage of Table, analyze its features, and how to implement similar functionality on other platforms.
SwiftUI Overlay Container 2: Customizable, Efficient, and Convenient View Manager
SwiftUI Overlay Container is a view container component for SwiftUI. It is a customizable, efficient, and convenient view manager. With just a simple configuration, the SwiftUI Overlay Container can handle basic tasks such as view organization, queue processing, transitions, animations, interactions, and display style configuration. This allows developers to focus more on the implementation of the application's views themselves.
SwiftUIOverlayContainer — A SwiftUI Library for Creating Customized Popup Views
SwiftUI currently offers popup views such as sheet, fullScreenCover, alert, action sheet, etc. to enrich UI interactions. However, the variety is somewhat limited. To write code for various popup windows more conveniently, I created a simple SwiftUI library — SwiftUIOverlayContainer.