fix(ios): 修复iOS摄像头对焦异常，优化多摄选择逻辑

1. 重构iOS原生对焦插件，支持按摄像头名称精准匹配设备
2. 优化摄像头选择逻辑，优先选用后置主摄并排除长焦/超广角镜头
3. 修复连续自动对焦失效问题，增加延迟初始化和定期校验
4. 添加调试日志便于排查摄像头相关问题

Assets/Plugins/iOS/CameraFocusHelper.mm

@@ -1,23 +1,64 @@
 #import <AVFoundation/AVFoundation.h>
 #import <UIKit/UIKit.h>
 
+/// 通过名称查找摄像头设备
+static AVCaptureDevice *FindCameraByName(const char *cameraName)
+{
+    if (cameraName == NULL || strlen(cameraName) == 0) {
+        return [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
+    }
+
+    NSString *name = [NSString stringWithUTF8String:cameraName];
+
+    // iOS 10+ DiscoverySession
+    if (@available(iOS 10.0, *)) {
+        AVCaptureDeviceDiscoverySession *session = [AVCaptureDeviceDiscoverySession
+            discoverySessionWithDeviceTypes:@[AVCaptureDeviceTypeBuiltInWideAngleCamera,
+                                              AVCaptureDeviceTypeBuiltInTelephotoCamera,
+                                              AVCaptureDeviceTypeBuiltInUltraWideCamera]
+                                  mediaType:AVMediaTypeVideo
+                                   position:AVCaptureDevicePositionUnspecified];
+        for (AVCaptureDevice *device in session.devices) {
+            if ([device.localizedName containsString:name] ||
+                [device.modelID containsString:name]) {
+                return device;
+            }
+        }
+        // 没找到精确匹配，返回第一个活跃的
+        for (AVCaptureDevice *device in session.devices) {
+            if (device.isConnected && !device.isSuspended) {
+                return device;
+            }
+        }
+    }
+
+    return [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
+}
+
 extern "C" {
 
-    /// 启用连续自动对焦和自动曝光
+    /// 启用连续自动对焦和自动曝光（传入 C# 选中的摄像头名称）
-    void _EnableContinuousAutoFocus()
+    void _EnableContinuousAutoFocus(const char *cameraName)
     {
         dispatch_async(dispatch_get_main_queue(), ^{
-            AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
+            AVCaptureDevice *device = FindCameraByName(cameraName);
-            if (!device) return;
+            if (!device) {
+                NSLog(@"[CameraFocusHelper] 未找到摄像头设备");
+                return;
+            }
+
+            NSLog(@"[CameraFocusHelper] 配置设备: %@ (name=%@, model=%@)",
+                  device.localizedName, device.localizedName, device.modelID);
 
             NSError *error = nil;
-
-            // 锁定设备开始配置
             if ([device lockForConfiguration:&error]) {
 
-                // 连续自动对焦模式（持续调整，适合扫描二维码）
+                // 连续自动对焦
                 if ([device isFocusModeSupported:AVCaptureFocusModeContinuousAutoFocus]) {
                     device.focusMode = AVCaptureFocusModeContinuousAutoFocus;
+                    NSLog(@"[CameraFocusHelper] 已设为连续自动对焦");
+                } else {
+                    NSLog(@"[CameraFocusHelper] 设备不支持连续自动对焦");
                 }
 
                 // 连续自动曝光
@@ -25,36 +66,34 @@ extern "C" {
                     device.exposureMode = AVCaptureExposureModeContinuousAutoExposure;
                 }
 
-                // 对焦范围限制为近距（适合二维码）
+                // 对焦范围限制为近距
-                if ([device respondsToSelector:@selector(setAutoFocusRangeRestriction:)]) {
+                if ([device respondsToSelector:@selector(isAutoFocusRangeRestrictionSupported)] &&
-                    if ([device isAutoFocusRangeRestrictionSupported]) {
+                    [device isAutoFocusRangeRestrictionSupported]) {
                     device.autoFocusRangeRestriction = AVCaptureAutoFocusRangeRestrictionNear;
-                    }
+                    NSLog(@"[CameraFocusHelper] 已设对焦范围为近距");
                 }
 
                 [device unlockForConfiguration];
-
+                NSLog(@"[CameraFocusHelper] 摄像头配置完成");
-                NSLog(@"[CameraFocusHelper] 已启用连续自动对焦");
             } else {
-                NSLog(@"[CameraFocusHelper] 锁定设备失败: %@", error.localizedDescription);
+                NSLog(@"[CameraFocusHelper] lockForConfiguration 失败: %@", error.localizedDescription);
             }
         });
     }
 
-    /// 触发一次自动对焦（用于手动点按时调用）
+    /// 确保连续自动对焦仍在生效（传入 C# 选中的摄像头名称）
-    void _TriggerAutoFocus()
+    void _EnsureContinuousAutoFocus(const char *cameraName)
     {
         dispatch_async(dispatch_get_main_queue(), ^{
-            AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
+            AVCaptureDevice *device = FindCameraByName(cameraName);
             if (!device) return;
 
             NSError *error = nil;
             if ([device lockForConfiguration:&error]) {
-                if ([device isFocusModeSupported:AVCaptureFocusModeAutoFocus]) {
+                if (device.focusMode != AVCaptureFocusModeContinuousAutoFocus &&
-                    device.focusMode = AVCaptureFocusModeAutoFocus;
+                    [device isFocusModeSupported:AVCaptureFocusModeContinuousAutoFocus]) {
-                }
+                    device.focusMode = AVCaptureFocusModeContinuousAutoFocus;
-                if ([device isExposureModeSupported:AVCaptureExposureModeAutoExpose]) {
+                    NSLog(@"[CameraFocusHelper] 重新设回连续自动对焦");
-                    device.exposureMode = AVCaptureExposureModeAutoExpose;
                 }
                 [device unlockForConfiguration];
             }

Assets/Scripts/UI/Pages/ConnectDevice/ScanQRcode.cs

@@ -45,10 +45,10 @@ namespace Kill.UI.Pages
 
 #if UNITY_IOS && !UNITY_EDITOR
         [DllImport("__Internal")]
-        private static extern void _EnableContinuousAutoFocus();
+        private static extern void _EnableContinuousAutoFocus(string cameraName);
 
         [DllImport("__Internal")]
-        private static extern void _TriggerAutoFocus();
+        private static extern void _EnsureContinuousAutoFocus(string cameraName);
 #endif
         // 摄像头相关
         private WebCamTexture webCamTexture;
@@ -59,6 +59,9 @@ namespace Kill.UI.Pages
         // 扫描结果回调
         public event Action<string> OnQRCodeScanned;
 
+        // iOS 摄像头名称（供原生对焦插件使用）
+        private string selectedCameraName;
+
         void OnEnable()
         {
             StartScan();
@@ -148,17 +151,32 @@ namespace Kill.UI.Pages
                 yield break;
             }
 
-            // 优先使用后置摄像头，并选择支持自动对焦的摄像头
+            // 优先使用后置主摄（广角），iOS 多摄设备排除超广角/长焦
             string deviceName = devices[0].name;
+            currentDevice = devices[0];
             for (int i = 0; i < devices.Length; i++)
             {
                 if (!devices[i].isFrontFacing)
+                {
+                    string lowerName = devices[i].name.ToLower();
+                    // iOS 多摄命名: "Back Camera", "Telephoto Camera", "Ultra Wide Camera"
+                    // 优先选不带 telephoto/ultra wide 的后置摄像头（即主摄）
+                    if (!lowerName.Contains("telephoto") && !lowerName.Contains("ultra wide"))
                     {
                         deviceName = devices[i].name;
                         currentDevice = devices[i];
                         break;
                     }
+                    // 兜底：第一个后置
+                    if (deviceName == devices[0].name)
+                    {
+                        deviceName = devices[i].name;
+                        currentDevice = devices[i];
                     }
+                }
+            }
+            Debug.Log($"[ScanQRcode] 选中摄像头: {deviceName}");
+            selectedCameraName = deviceName;
             RectTransform cameraPreviewRect=cameraPreview.GetComponent<RectTransform>();
             // 使用较低的扫描分辨率以提高性能
             int targetWidth = 2160;
@@ -172,11 +190,13 @@ namespace Kill.UI.Pages
             // 等待摄像头启动
             yield return new WaitUntil(() => webCamTexture.width > 100);
 
-            // iOS: 调用原生插件强制开启连续自动对焦
+            // iOS: 延迟后调用原生插件强制开启连续自动对焦
+            // (等待 Unity 内部 AVCaptureSession 完全就绪)
 #if UNITY_IOS && !UNITY_EDITOR
             if (enableAutoFocus)
             {
-                _EnableContinuousAutoFocus();
+                yield return new WaitForSeconds(1.5f);
+                _EnableContinuousAutoFocus(deviceName);
             }
 #endif
             // 调整预览画面比例
@@ -287,7 +307,7 @@ namespace Kill.UI.Pages
 
         /// <summary>
         /// 自动对焦维护协程
-        /// iOS: 走原生插件（连续自动对焦已启用，只需定期触发即可）
+        /// iOS: 走原生插件周期确保连续对焦模式不被重置
         /// 其他平台: 使用 WebCamTexture.autoFocusPoint 定期设置对焦点
         /// </summary>
         private IEnumerator AutoFocusCoroutine()
@@ -295,8 +315,11 @@ namespace Kill.UI.Pages
             while (isScanning)
             {
 #if UNITY_IOS && !UNITY_EDITOR
-                // iOS 通过原生插件触发一次自动对焦
+                // iOS 通过原生插件确保连续自动对焦仍在生效
-                _TriggerAutoFocus();
+                if (!string.IsNullOrEmpty(selectedCameraName))
+                {
+                    _EnsureContinuousAutoFocus(selectedCameraName);
+                }
 #else
                 // Android/其他: 定期重置对焦点到画面中心
                 if (webCamTexture != null && webCamTexture.isPlaying)