晚上扫描会自动感光打开手电筒吗

[zhangkn]

这个很简单，可以自己监听代理方法。

具体是这样的：（brightnessValue 值代表光线强度，值越小代表光线越暗）

` @property (nonatomic, strong) AVCaptureVideoDataOutput *videoDataOutput; // 创建摄像数据输出流，用于识别光线强弱 _videoDataOutput = [[AVCaptureVideoDataOutput alloc] init];

/// MARK: Defines an interface for delegates of AVCaptureVideoDataOutput to receive captured video sample buffers and be notified of late sample buffers that were dropped. // /// MARK: 亮度变化

• (void)captureOutput:(AVCaptureOutput )output didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection )connection { CFDictionaryRef metadataDict = CMCopyDictionaryOfAttachments(NULL, sampleBuffer, kCMAttachmentMode_ShouldPropagate); NSDictionary metadata = [[NSDictionary alloc] initWithDictionary:(__bridge NSDictionary )metadataDict]; CFRelease(metadataDict); NSDictionary exifDictionary = [metadata objectForKey:(NSString )kCGImagePropertyExifDictionary]; float brightness = [[exifDictionary objectForKey:(NSString *)kCGImagePropertyExifBrightnessValue] floatValue]; if (brightness > 0) { // 光线明亮，隐藏按钮 [self.maskView hideLightButton]; } else { // 光线昏暗，显示按钮 [self.maskView showLightButton]; }

} `