Recently, I started building a video player that uses CoreText to render subtitles. However, when scrolling through the UI, the frame rate dropped to an unacceptable 15 FPS. To fix this, I created a demo that wraps a native text view with CoreText rendering, eventually optimizing the performance to a smooth 60 FPS.
I remember when I first graduated and started iOS game development, I used NSThread directly for multithreading. When GCD (Grand Central Dispatch) was introduced, it was very convenient to use, and I used it almost exclusively. occasionally, when tasks had dependencies, I would use NSOperation.
I hadn’t noticed loadViewIfNeeded before. Usually I just access vc.view to force the view to load. loadViewIfNeeded is definitely clearer and more explicit—it avoids accidental side-effects when you only want to load the view conditionally.
You can view the full GitHub Workflows file here.
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Many developers complain about SwiftUI because some of its behaviours feel counter-intuitive. For example, in the code at #1, if you comment out the .padding() modifier, the entire area above the search field turns red. That happens because the background of the search view bleeds into its parent container. If you don’t want the Search view’s background to affect the parent view, you have to break that view hierarchy connection.
Before iOS 16, you could get the ScrollView’s offset using the following code. However, if the UI becomes complex, the scrollViewOffset will not update while scrolling.
I wrapped my view in a NavigationStack and used .toolbarVisibility(.hidden, for: .tabBar) to navigate while hiding the tab bar. However, this causes an issue: the transition animation becomes stiff and unnatural. I haven’t found a good solution yet.
In Swift, Type Erasure is a key concept for understanding protocols and generics.
上一次认真思考“如何学习”这件事，还是在看 Scott 那本书的时候。他一年之内自学完了四年制大学的 CS 课程。最近我又开始有点迷茫。快四十了，后端不算真正精通，iOS 技能也荒废了，语言也没学好。这些问题叠在一起，让我压力很大。结果又开始玩 Dota 2 来逃避。