我已经将AVCaptureDeviceTorchMode设置为AVCaptureTorchModeAuto，在AVCaptureSession开始运行后设置手电筒模式。根据Apple的文档，我希望手电筒模式能够在弱光条件下点亮LED:https://developer.apple.com/library/ios/documentation/AVFoundation/Reference/AVCaptureDevice_Class/Reference/Reference.html#//apple_ref/doc/c_ref/AVCaptureTorchMode但是，在我的测试设备(iPho

我已经将AVCaptureDeviceTorchMode设置为AVCaptureTorchModeAuto，在AVCaptureSession开始运行后设置手电筒模式。根据Apple的文档，我希望手电筒模式能够在弱光条件下点亮LED:https://developer.apple.com/library/ios/documentation/AVFoundation/Reference/AVCaptureDevice_Class/Reference/Reference.html#//apple_ref/doc/c_ref/AVCaptureTorchMode但是，在我的测试设备(iPho