feat(iOS): 新增原生相机对焦插件并适配扫码页面

1. 新增iOS平台原生相机对焦辅助插件，支持开启连续自动对焦和点击单点对焦
2. 适配扫码页面，iOS平台使用原生插件实现对焦功能，修复Unity自带autoFocusPoint无效问题
3. 添加点击屏幕触发单点对焦，1.5秒后自动恢复连续对焦
4. 新增定时维护对焦状态的协程，防止系统重置对焦模式

Assets/Plugins/iOS/CameraFocusHelper.mm

@@ -0,0 +1,71 @@
+#import <AVFoundation/AVFoundation.h>
+#import <UIKit/UIKit.h>
+
+/// 获取当前正在使用的后置摄像头设备
+static AVCaptureDevice *GetActiveRearCamera(void)
+{
+    // 遍历所有正在运行的 AVCaptureSession，找到后置摄像头的输入
+    if (@available(iOS 10.0, *)) {
+        AVCaptureDeviceDiscoverySession *session = [AVCaptureDeviceDiscoverySession
+            discoverySessionWithDeviceTypes:@[AVCaptureDeviceTypeBuiltInWideAngleCamera]
+                                  mediaType:AVMediaTypeVideo
+                                   position:AVCaptureDevicePositionBack];
+        for (AVCaptureDevice *d in session.devices) {
+            if (d.deviceType == AVCaptureDeviceTypeBuiltInWideAngleCamera) {
+                return d;
+            }
+        }
+    }
+    return [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
+}
+
+extern "C" {
+
+    /// 开启连续自动对焦
+    void _EnableContinuousAutoFocus(void)
+    {
+        AVCaptureDevice *device = GetActiveRearCamera();
+        if (!device) return;
+
+        NSError *error = nil;
+        if ([device lockForConfiguration:&error]) {
+            if ([device isFocusModeSupported:AVCaptureFocusModeContinuousAutoFocus]) {
+                device.focusMode = AVCaptureFocusModeContinuousAutoFocus;
+                NSLog(@"[CameraFocusHelper] 已开启连续自动对焦");
+            }
+            if ([device isExposureModeSupported:AVCaptureExposureModeContinuousAutoExposure]) {
+                device.exposureMode = AVCaptureExposureModeContinuousAutoExposure;
+            }
+            [device unlockForConfiguration];
+        } else {
+            NSLog(@"[CameraFocusHelper] 配置失败: %@", error.localizedDescription);
+        }
+    }
+
+    /// 触发单次自动对焦（点击对焦用）
+    void _TriggerAutoFocus(float normalizedX, float normalizedY)
+    {
+        AVCaptureDevice *device = GetActiveRearCamera();
+        if (!device) return;
+
+        NSError *error = nil;
+        if ([device lockForConfiguration:&error]) {
+            if ([device isFocusPointOfInterestSupported]) {
+                device.focusPointOfInterest = CGPointMake(normalizedX, normalizedY);
+                device.focusMode = AVCaptureFocusModeAutoFocus;
+            }
+            if ([device isExposurePointOfInterestSupported]) {
+                device.exposurePointOfInterest = CGPointMake(normalizedX, normalizedY);
+                device.exposureMode = AVCaptureExposureModeAutoExpose;
+            }
+            [device unlockForConfiguration];
+
+            // 1.5秒后恢复连续对焦
+            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.5 * NSEC_PER_SEC)),
+                           dispatch_get_main_queue(), ^{
+                _EnableContinuousAutoFocus();
+            });
+        }
+    }
+
+}

Assets/Plugins/iOS/CameraFocusHelper.mm.meta

@@ -0,0 +1,33 @@
+fileFormatVersion: 2
+guid: bfac996797a54a14fa60abaaaf887145
+PluginImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  iconMap: {}
+  executionOrder: {}
+  defineConstraints: []
+  isPreloaded: 0
+  isOverridable: 0
+  isExplicitlyReferenced: 0
+  validateReferences: 1
+  platformData:
+  - first:
+      Any: 
+    second:
+      enabled: 0
+      settings: {}
+  - first:
+      Editor: Editor
+    second:
+      enabled: 0
+      settings:
+        DefaultValueInitialized: true
+  - first:
+      iPhone: iOS
+    second:
+      enabled: 1
+      settings:
+        AddToEmbeddedBinaries: false
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

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

@@ -1,6 +1,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Runtime.InteropServices;
 using Kill.UI.Components;
 using UnityEngine;
 using UnityEngine.UI;
@@ -41,6 +42,15 @@ namespace Kill.UI.Pages
         public bool enableAutoFocus = true;
         [Tooltip("对焦间隔（秒）")]
         public float focusInterval = 1f;
+
+#if UNITY_IOS && !UNITY_EDITOR
+        [DllImport("__Internal")]
+        private static extern void _EnableContinuousAutoFocus();
+
+        [DllImport("__Internal")]
+        private static extern void _TriggerAutoFocus(float normalizedX, float normalizedY);
+#endif
+
         // 摄像头相关
         private WebCamTexture webCamTexture;
         private WebCamDevice currentDevice;
@@ -60,6 +70,22 @@ namespace Kill.UI.Pages
             StopScan();
         }
 
+        void Update()
+        {
+#if UNITY_IOS && !UNITY_EDITOR
+            if (isScanning && Input.touchCount > 0)
+            {
+                Touch touch = Input.GetTouch(0);
+                if (touch.phase == TouchPhase.Began)
+                {
+                    float normX = touch.position.x / Screen.width;
+                    float normY = touch.position.y / Screen.height;
+                    _TriggerAutoFocus(normX, normY);
+                }
+            }
+#endif
+        }
+
         /// <summary>
         /// 开始扫描
         /// </summary>
@@ -151,18 +177,22 @@ namespace Kill.UI.Pages
                 }
             }
             RectTransform cameraPreviewRect=cameraPreview.GetComponent<RectTransform>();
-            // 使用较低的扫描分辨率以提高性能
+            // 使用 1080p 分辨率
-            int targetWidth = 2160;
+            webCamTexture = new WebCamTexture(deviceName, 1920, 1080, 30);
-            
-            // 创建摄像头纹理
-            webCamTexture = new WebCamTexture(deviceName, targetWidth, 30);
 
             // 开始播放
             webCamTexture.Play();
 
             // 等待摄像头启动
             yield return new WaitUntil(() => webCamTexture.width > 100);
-            webCamTexture.autoFocusPoint=new Vector2(0.5f,0.5f);
+
+#if UNITY_IOS && !UNITY_EDITOR
+            // iOS: 通过原生插件开启连续自动对焦（autoFocusPoint 在 iOS 无效）
+            _EnableContinuousAutoFocus();
+            // 定期维护对焦状态，防止被系统重置
+            StartCoroutine(IOsFocusMaintainCoroutine());
+#endif
+            webCamTexture.autoFocusPoint = new Vector2(0.5f, 0.5f);
             // 调整预览画面比例
             AdjustPreviewAspect();
             
@@ -215,7 +245,21 @@ namespace Kill.UI.Pages
             
             Debug.Log($"[ScanQRcode] 预览调整 - 相机: {cameraWidth}x{cameraHeight}, 预览: {previewWidth}x{previewHeight}");
         }
-        
+
+#if UNITY_IOS && !UNITY_EDITOR
+        /// <summary>
+        /// iOS 对焦维护协程 — 定期重新设置连续自动对焦，防止被系统重置
+        /// </summary>
+        private IEnumerator IOsFocusMaintainCoroutine()
+        {
+            while (isScanning)
+            {
+                yield return new WaitForSeconds(3f);
+                _EnableContinuousAutoFocus();
+            }
+        }
+#endif
+
         private Texture2D previewTexture;
         
         /// <summary>