fix: QR scanner - move camera init to background thread, window shows immediately

Sources/QRScannerView.swift

@@ -4,16 +4,17 @@ import AVFoundation
 #if os(macOS)
 import AppKit
 
-// MARK: - 扫码窗口（独立 NSWindow，避免 SwiftUI sheet 布局崩溃）
+// MARK: - 扫码窗口控制器（独立 NSWindow）
 class QRScannerWindowController: NSObject, AVCaptureMetadataOutputObjectsDelegate {
     var window: NSWindow?
     var session: AVCaptureSession?
-    var previewLayer: AVCaptureVideoPreviewLayer?
-    var hostView: QRScannerHostView?
     weak var bridge: PlayerBridge?
     
     private var lastDetected: String?
     private var lastDetectedTime: Date = .distantPast
+    private weak var resultLabel: NSTextField?
+    private weak var previewHost: NSView?
+    private weak var loadingLabel: NSTextField?
     
     init(bridge: PlayerBridge) {
         self.bridge = bridge
@@ -36,25 +37,37 @@ class QRScannerWindowController: NSObject, AVCaptureMetadataOutputObjectsDelegat
         win.isReleasedWhenClosed = false
         win.center()
         
-        // 创建宿主视图
+        let container = NSView(frame: win.contentView!.bounds)
-        let container = NSView(frame: win.contentRect(forFrameRect: win.frame).insetBy(dx: 0, dy: 0))
+        container.autoresizingMask = [.width, .height]
         container.wantsLayer = true
         container.layer?.backgroundColor = NSColor.black.cgColor
         
-        let hostView = QRScannerHostView(frame: NSRect(x: 20, y: 80, width: 360, height: 240))
+        // 摄像头预览区域（占位）
-        container.addSubview(hostView)
+        let previewHost = NSView(frame: NSRect(x: 20, y: 80, width: 360, height: 240))
-        self.hostView = hostView
+        previewHost.wantsLayer = true
+        previewHost.layer?.backgroundColor = NSColor.darkGray.cgColor
+        previewHost.autoresizingMask = [.width, .height]
+        container.addSubview(previewHost)
+        self.previewHost = previewHost
+        
+        // "正在初始化摄像头..." 提示
+        let loadingLabel = NSTextField(labelWithString: "Initializing camera...")
+        loadingLabel.font = NSFont.systemFont(ofSize: 12)
+        loadingLabel.textColor = .secondaryLabelColor
+        loadingLabel.frame = NSRect(x: 0, y: 100, width: 360, height: 40)
+        loadingLabel.alignment = .center
+        previewHost.addSubview(loadingLabel)
+        self.loadingLabel = loadingLabel
         
         // 提示文字
-        let label = NSTextField(labelWithString: L.scanHint)
+        let hintLabel = NSTextField(wrappingLabelWithString: L.scanHint)
-        label.font = NSFont.systemFont(ofSize: 11)
+        hintLabel.font = NSFont.systemFont(ofSize: 11)
-        label.textColor = .secondaryLabelColor
+        hintLabel.textColor = .secondaryLabelColor
-        label.frame = NSRect(x: 20, y: 20, width: 360, height: 40)
+        hintLabel.frame = NSRect(x: 20, y: 20, width: 360, height: 40)
-        label.alignment = .center
+        hintLabel.alignment = .center
-        label.lineBreakMode = .byWordWrapping
+        container.addSubview(hintLabel)
-        container.addSubview(label)
         
-        // 检测结果文字
+        // 检测结果
         let resultLabel = NSTextField(labelWithString: "")
         resultLabel.font = NSFont.monospacedSystemFont(ofSize: 12, weight: .regular)
         resultLabel.textColor = .labelColor
@@ -63,29 +76,41 @@ class QRScannerWindowController: NSObject, AVCaptureMetadataOutputObjectsDelegat
         resultLabel.lineBreakMode = .byTruncatingMiddle
         resultLabel.tag = 100
         container.addSubview(resultLabel)
+        self.resultLabel = resultLabel
         
         win.contentView = container
-        
-        // 配置摄像头
-        setupCapture(hostView: hostView)
-        
         win.makeKeyAndOrderFront(nil)
         NSApp.activate(ignoringOtherApps: true)
         self.window = win
+        
+        // 后台初始化摄像头（不阻塞主线程）
+        DispatchQueue.global(qos: .userInitiated).async { [weak self] in
+            self?.setupCaptureOnBackground(previewHost: previewHost)
+        }
     }
     
     func close() {
         session?.stopRunning()
-        window?.close()
+        DispatchQueue.main.async { [weak self] in
+            self?.window?.close()
+        }
     }
     
-    private func setupCapture(hostView: QRScannerHostView) {
+    // 在后台线程初始化摄像头
+    private func setupCaptureOnBackground(previewHost: NSView) {
         let session = AVCaptureSession()
-        self.session = session
         
-        guard let device = AVCaptureDevice.default(for: .video),
+        guard let device = AVCaptureDevice.default(for: .video) else {
-              let input = try? AVCaptureDeviceInput(device: device) else {
+            DispatchQueue.main.async { [weak self] in
-            showError("No camera available")
+                self?.showError("No camera available")
+            }
+            return
+        }
+        
+        guard let input = try? AVCaptureDeviceInput(device: device) else {
+            DispatchQueue.main.async { [weak self] in
+                self?.showError("Cannot access camera")
+            }
             return
         }
         
@@ -102,22 +127,34 @@ class QRScannerWindowController: NSObject, AVCaptureMetadataOutputObjectsDelegat
         
         let previewLayer = AVCaptureVideoPreviewLayer(session: session)
         previewLayer.videoGravity = .resizeAspectFill
-        hostView.previewLayer = previewLayer
-        self.previewLayer = previewLayer
         
-        // 后台启动
+        self.session = session
-        DispatchQueue.global(qos: .userInitiated).async { [weak self] in
+        
+        // 回到主线程更新 UI
+        DispatchQueue.main.async { [weak self] in
+            guard let self = self, previewHost.window != nil else {
+                // 窗口已关闭，停止
+                session.stopRunning()
+                return
+            }
+            
+            // 移除 loading 提示
+            self.loadingLabel?.removeFromSuperview()
+            
+            // 添加预览层
+            previewLayer.frame = previewHost.bounds
+            previewHost.layer?.addSublayer(previewLayer)
+            
+            // 启动会话（后台启动避免阻塞）
+            DispatchQueue.global(qos: .userInitiated).async {
                 session.startRunning()
-            DispatchQueue.main.async {
-                self?.previewLayer?.frame = hostView.bounds
             }
         }
     }
     
     private func showError(_ msg: String) {
-        guard let resultLabel = window?.contentView?.viewWithTag(100) as? NSTextField else { return }
+        resultLabel?.stringValue = msg
-        resultLabel.stringValue = msg
+        resultLabel?.textColor = .systemRed
-        resultLabel.textColor = .systemRed
     }
     
     // MARK: - AVCaptureMetadataOutputObjectsDelegate
@@ -125,7 +162,6 @@ class QRScannerWindowController: NSObject, AVCaptureMetadataOutputObjectsDelegat
         guard let metadata = metadataObjects.first as? AVMetadataMachineReadableCodeObject,
               let code = metadata.stringValue else { return }
         
-        // 防抖 3 秒
         let now = Date()
         if code == lastDetected, now.timeIntervalSince(lastDetectedTime) < 3 {
             return
@@ -134,18 +170,14 @@ class QRScannerWindowController: NSObject, AVCaptureMetadataOutputObjectsDelegat
         lastDetectedTime = now
         
         // 显示检测结果
-        if let resultLabel = window?.contentView?.viewWithTag(100) as? NSTextField {
+        resultLabel?.stringValue = code
-            resultLabel.stringValue = code
+        resultLabel?.textColor = .systemGreen
-            resultLabel.textColor = .systemGreen
-        }
         
-        // 检查是否为有效 URL
+        // 有效 URL → 添加并播放
         if let url = URL(string: code), (url.scheme == "http" || url.scheme == "https") {
             DispatchQueue.main.async { [weak self] in
                 self?.bridge?.addURL(code)
             }
-            
-            // 延迟关闭
             DispatchQueue.main.asyncAfter(deadline: .now() + 1.5) { [weak self] in
                 self?.close()
             }
@@ -157,23 +189,4 @@ class QRScannerWindowController: NSObject, AVCaptureMetadataOutputObjectsDelegat
     }
 }
 
-// MARK: - 宿主视图
-class QRScannerHostView: NSView {
-    var previewLayer: AVCaptureVideoPreviewLayer?
-    
-    override init(frame: CGRect) {
-        super.init(frame: frame)
-        wantsLayer = true
-    }
-    
-    required init?(coder: NSCoder) {
-        fatalError("init(coder:) has not been implemented")
-    }
-    
-    override func layout() {
-        super.layout()
-        previewLayer?.frame = bounds
-    }
-}
-
 #endif