ios - 在 iOS 中访问环境光传感器

Question

我正在开展一个项目，在该项目中确实需要访问环境光传感器。

我在 Google 和 Stackoverflow 中搜索了很多，但找不到任何有用的信息。甚至有可能这样做吗？

我还尝试通过计算相机输入的亮度来计算环境光值，但结果并不精确，因为相机对图像进行了大量调整，这会扭曲结果。

Answer 1

读取环境光传感器数据，需要使用IOKit框架中的IOHID（参考）

http://iphonedevwiki.net/index.php/AppleISL29003

http://iphonedevwiki.net/index.php/IOKit.framework

Answer 2

我通过访问相机解决了这个问题

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection: (AVCaptureConnection *)connection
{
 CFDictionaryRef metadataDict = CMCopyDictionaryOfAttachments(NULL,
sampleBuffer, kCMAttachmentMode_ShouldPropagate);
NSDictionary *metadata = [[NSMutableDictionary alloc]
                          initWithDictionary:(__bridge NSDictionary*)metadataDict];
CFRelease(metadataDict);
NSDictionary *exifMetadata = [[metadata objectForKey:(NSString *)kCGImagePropertyExifDictionary] mutableCopy];
float brightnessValue = [[exifMetadata objectForKey:(NSString *)kCGImagePropertyExifBrightnessValue] floatValue];

//THIS IS INFORMATION THAT COMES FROM THE SENSOR
_Sensor = [[NSNumber numberWithFloat:brightnessValue] stringValue];
 NSLog(@" %@",_Sensor);

dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, 0.5 * NSEC_PER_SEC);
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){


        if ([_Sensor isEqualToString:@"-5.575654"]) {

       // YOU CODE HER

        }
        else {

       // YOU CODE HER
    }

});

}