listless

A simple list app for Apple platforms
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KeyboardWarmup.swift (1476B)

      1 import UIKit
      2 
      3 /// Pre-pays the ~400ms `RemoteTextInput` / autocorrect subsystem spin-up that
      4 /// otherwise happens on the first real text field focus after a cold launch.
      5 /// Creates an offscreen `UITextField`, makes it first responder, then resigns
      6 /// immediately — enough to trigger the keyboard process to initialize without
      7 /// visibly animating anything.
      8 @MainActor
      9 enum KeyboardWarmup {
     10     private static var didWarm = false
     11 
     12     static func prime() {
     13         guard !didWarm else { return }
     14         guard let window = keyWindow() else { return }
     15         didWarm = true
     16 
     17         PerfSampler.shared.measure("Keyboard.warmup") {
     18             let field = UITextField(frame: CGRect(x: -100, y: -100, width: 1, height: 1))
     19             field.autocorrectionType = .default
     20             field.autocapitalizationType = .sentences
     21             window.addSubview(field)
     22             field.becomeFirstResponder()
     23             field.resignFirstResponder()
     24             field.removeFromSuperview()
     25         }
     26     }
     27 
     28     private static func keyWindow() -> UIWindow? {
     29         for case let scene as UIWindowScene in UIApplication.shared.connectedScenes {
     30             if let key = scene.windows.first(where: \.isKeyWindow) {
     31                 return key
     32             }
     33         }
     34         for case let scene as UIWindowScene in UIApplication.shared.connectedScenes {
     35             if let first = scene.windows.first {
     36                 return first
     37             }
     38         }
     39         return nil
     40     }
     41 }