UIImagePickerController相册正常但相机报exposureBiasesByMode错误如何解决

错误产生原因 #

• 该exposureBiasesByMode相关报错绝大多数是iOS 15及以上版本的系统内部日志冗余，本身不会导致功能崩溃，如果相机只是打印该报错但可以正常使用，属于正常现象。
• 如果伴随报错相机完全无法启动，常见原因有两个：
  1. 项目Info.plist缺少相机权限声明NSCameraUsageDescription，系统直接拒绝相机访问触发错误。
  2. 全局复用同一个UIImagePickerController实例，在相册和相机之间切换sourceType时，系统内部相机参数没有正确重置，导致读取曝光配置失败。

修复方案 #

• 方案1：补全权限配置
  在项目Info.plist中添加相机权限声明，右键Info.plist选择Open As -> Source Code，添加如下代码：

  <key>NSCameraUsageDescription</key>
  <string>需要访问您的相机拍摄照片</string>
  

  也可以在可视化界面添加Privacy - Camera Usage Description项，值填写自定义的权限提示文案即可。

• 方案2：不复用UIImagePickerController实例
  修改ImagePicker类逻辑，每次调用对应功能时重新初始化picker，避免切换来源时的参数冲突：

  open class ImagePicker: NSObject {
      private weak var presentationController: UIViewController?
      private weak var delegate: ImagePickerDelegate?
      // 临时持有当前使用的picker避免提前释放
      private var currentPicker: UIImagePickerController?
  
      public init(presentationController: UIViewController, delegate: ImagePickerDelegate) {
          super.init()
          self.presentationController = presentationController
          self.delegate = delegate
      }
  
      private func action(for type: UIImagePickerController.SourceType, title: String) -> UIAlertAction? {
          guard UIImagePickerController.isSourceTypeAvailable(type) else {
              return nil
          }
          
          return UIAlertAction(title: title, style: .default) { [unowned self] _ in
              let picker = UIImagePickerController()
              picker.delegate = self
              picker.allowsEditing = true
              picker.mediaTypes = ["public.image"]
              picker.sourceType = type
              self.currentPicker = picker
              self.presentationController?.present(picker, animated: true)
          }
      }
  
      func openCamera() {
          guard UIImagePickerController.isSourceTypeAvailable(.camera) else { return }
          let picker = UIImagePickerController()
          picker.delegate = self
          picker.allowsEditing = true
          picker.mediaTypes = ["public.image"]
          picker.sourceType = .camera
          currentPicker = picker
          presentationController?.present(picker, animated: true)
      }
  
      func openPhotoLibrary() {
          guard UIImagePickerController.isSourceTypeAvailable(.photoLibrary) else { return }
          let picker = UIImagePickerController()
          picker.delegate = self
          picker.allowsEditing = true
          picker.mediaTypes = ["public.image"]
          picker.sourceType = .photoLibrary
          currentPicker = picker
          presentationController?.present(picker, animated: true)
      }
  
      public func present(from sourceView: UIView) {
          // 原有逻辑保持不变
      }
  
      private func pickerController(_ controller: UIImagePickerController, didSelect image: UIImage?) {
          controller.dismiss(animated: true, completion: nil)
          self.delegate?.didSelect(image: image)
          // 用完释放picker
          self.currentPicker = nil
      }
  }
  
  extension ImagePicker: UIImagePickerControllerDelegate, UINavigationControllerDelegate {
      // 原有代理逻辑保持不变
  }
  

• 方案3：忽略系统日志
  如果相机功能完全正常，仅控制台打印该报错，可以直接忽略，属于iOS系统内部的打印bug，不会影响App功能和上架审核。

内容的提问来源于stack exchange，提问作者Jitendra Modi