如何用`AVFoundation检测相机存在？
问题描述：
现在iOS设备有0〜2个摄像头。如何检测它们？
Now iOS devices has 0~2 cameras. How to detect them?
答
您可以遍历视频设备...
You iterate through the video devices...
NSArray *videoDevices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
AVCaptureDevice *captureDevice = nil;
for (AVCaptureDevice *device in videoDevices) {
if (device.position == AVCaptureDevicePositionFront) {
//FRONT-FACING CAMERA EXISTS
}
}
当然，你也可以使用谓词更快一些，为了你的工作;）....（建议：使用filteredArrayUsingPredicate：方法在devicesWithMediaType：）
Of course you could also do this a bit quicker with a predicate, but i'll leave that for you to work out ;).... (HINT: use the filteredArrayUsingPredicate: method on the devicesWithMediaType:)