Try Sample AVCAM from apple found error

问题:

When I tried sample AVCAM swift with Xcode Version 9.0 beta 5 (9M202q). I found errors.

Undefined symbols for architecture x86_64:
"__T0So22AVCapturePhotoSettingsC12AVFoundation01_abC16SwiftNativeTypesACWP", referenced from: __T05AVCam20CameraViewControllerC12capturePhoto33_F53A4CF98D799BDDCA6C04BA14C549A1LLySo8UIButtonCFyycfU_ in CameraViewController.o
"__T012AVFoundation39_AVCapturePhotoSettingsSwiftNativeTypesPAAE016availablePreviewc11PixelFormatG0Says6UInt32VGfg", referenced from: __T05AVCam20CameraViewControllerC12capturePhoto33_F53A4CF98D799BDDCA6C04BA14C549A1LLySo8UIButtonCFyycfU_ in CameraViewController.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)

What is the problem? and How can fix that?

回答1:

Update 15 Sept 2017:

Official response from Apple:

Our apologies. For apps using Swift 3.2 or Swift 4.0, several AVFoundation capture APIs (public extensions on external protocol) were inadvertently marked private in Xcode 9. The following AVFoundation API are temporarily unavailable:

• AVCaptureDevice.Format.supportedColorSpaces

• AVCaptureDevice.supportedFlashModes

• AVCapturePhotoOutput.availablePhotoPixelFormatTypes

• AVCapturePhotoOutput.availableRawPhotoPixelFormatTypes

• AVCapturePhotoSettings.availablePreviewPhotoPixelFormatTypes

  As a workaround you can use the SwiftPrivate versions of these API by prepending each API with double underscore (__). For example, change AVCaptureDevice.Format.supportedColorSpaces to AVCaptureDevice.Format.__supportedColorSpaces.

I can confirm using __availablePreviewPhotoPixelFormatTypes fixes the build errors.

E.g.

let settings = AVCapturePhotoSettings()
let previewPixelType = settings.__availablePreviewPhotoPixelFormatTypes.first!

Source: https://forums.developer.apple.com/thread/86810#259270

---

Update 14 Sept 2017:

Issue reoccurs in Xcode 9.0 GM (9A235).

Filed new bug report for reference: rdar://34420979

---

Previous:

Update: Fixed in Xcode Beta 6.

Filed a bug report rdar://33935456 for Xcode Version 9.0 beta 5 (9M202q).

回答2:

Xcode 9.0 beta 5 (9M202q) definitely has a problem with AVCam Swift revision 2017-06-06. Fortunately the problem is isolated to these three lines in CameraViewController.swift:

if !photoSettings.availablePreviewPhotoPixelFormatTypes.isEmpty {
    photoSettings.previewPhotoFormat = [kCVPixelBufferPixelFormatTypeKey as String: photoSettings.availablePreviewPhotoPixelFormatTypes.first!]
}

Comment out the above code and AVCam will compile and run fine on a device running the latest iOS 11 beta.

回答3:

This appears to be an Xcode bug. The sample code builds fine in Xcode 9.0 beta (9M136h). Reported to Apple as rdar://33903950.

Update: Radar is now closed. Issue is fixed in Xcode 9.0 Beta 6 (9M214v).

回答4:

Try to add AVFoundation to linked frameworks (Target -> Build Phases -> Link Binary with Libraries)