检测 iPhone 应用程序中是否存在相机？

Question

我正在编写一个 iOS 应用程序，我需要能够检测设备是否有摄像头。以前，我会检查该设备是否是 iPhone，因为只有 iPhone 才有摄像头 - 但随着 iPod Touch 4 的推出，这不再是一个可行的选择。该应用程序无需相机即可运行，但相机的存在增加了功能。

那么，谁能给我提供返回是否有相机的代码？

Answer 1

您可以在 UIImagePickerController 中使用 +isSourceTypeAvailable: 方法：

if ([UIImagePickerController isSourceTypeAvailable: UIImagePickerControllerSourceTypeCamera])
   // Has camera

Answer 2

正如 Juan Boero 所写，检查：

    if UIImagePickerController.isSourceTypeAvailable(.camera) {...}

但我会添加另一个检查，以查看用户是否允许访问相机，正如苹果在其 PhotoPicker 示例中建议的那样（PhotoPicker 示例 Objective-C):

*请注意您必须导入 AVFoundation

SWIFT 5

    let authStatus = AVCaptureDevice.authorizationStatus(for: AVMediaType.video)
    switch authStatus {
        /*
         Status Restricted -
         The client is not authorized to access the hardware for the media type. The user cannot change the client's status, possibly due to active restrictions such as parental controls being in place.
         */
    case .denied, .restricted:
        // Denied access to camera
        // Explain that we need camera access and how to change it.
        let dialog = UIAlertController(title: "Unable to access the Camera", message: "To enable access, go to Settings > Privacy > Camera and turn on Camera access for this app.", preferredStyle: UIAlertController.Style.alert)

        let okAction = UIAlertAction(title: "OK", style: UIAlertAction.Style.default, handler: nil)

        dialog.addAction(okAction)
        self.present(dialog, animated:true, completion:nil)
    case .notDetermined:
        // The user has not yet been presented with the option to grant access to the camera hardware.
        // Ask for it.
        AVCaptureDevice.requestAccess(for: AVMediaType.video, completionHandler: { (grantd) in
        // If access was denied, we do not set the setup error message since access was just denied.
           if grantd {
           // Allowed access to camera, go ahead and present the UIImagePickerController.
            self.showImagePickerForSourceType(sourceType: UIImagePickerController.SourceType.camera)
            }
        })
    case .authorized:
        // Allowed access to camera, go ahead and present the UIImagePickerController.
        self.showImagePickerForSourceType(sourceType: UIImagePickerController.SourceType.camera)
    @unknown default:
        break; //handle other status
    }

SWIFT 3

let authStatus = AVCaptureDevice.authorizationStatus(forMediaType: AVMediaTypeVideo)
    
if authStatus == AVAuthorizationStatus.denied {
    // Denied access to camera
    // Explain that we need camera access and how to change it.
    let dialog = UIAlertController(title: "Unable to access the Camera", message: "To enable access, go to Settings > Privacy > Camera and turn on Camera access for this app.", preferredStyle: UIAlertControllerStyle.alert)
        
    let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: nil)
        
    dialog.addAction(okAction)
    self.present(dialog, animated:true, completion:nil)
        
} else if authStatus == AVAuthorizationStatus.notDetermined {     // The user has not yet been presented with the option to grant access to the camera hardware.
    // Ask for it.
    AVCaptureDevice.requestAccess(forMediaType: AVMediaTypeVideo, completionHandler: { (grantd) in
    // If access was denied, we do not set the setup error message since access was just denied.
       if grantd {
       // Allowed access to camera, go ahead and present the UIImagePickerController.
            self.showImagePickerForSourceType(sourceType: UIImagePickerControllerSourceType.camera)
        }
    })
} else {
        
    // Allowed access to camera, go ahead and present the UIImagePickerController.
    self.showImagePickerForSourceType(sourceType: UIImagePickerControllerSourceType.camera)

}

func showImagePickerForSourceType(sourceType: UIImagePickerControllerSourceType) {
    
    let myPickerController = UIImagePickerController()
    myPickerController.delegate = self;
    myPickerController.sourceType = sourceType  
    self.present(myPickerController, animated: true, completion: nil)
}

Answer 3

如果您使用 AV Foundation 类而不是 UIImagePickerController，您可以这样做：

BOOL hasCamera = ([[AVCaptureDevice devices] count] > 0);

如果您使用 UIImagePickerController 它可能不值得，因为您必须将 AVFoundation.framework 添加到您的项目中。

Answer 4

是的，有一个 API 可以做到这一点：

BOOL isCamera = [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera];

Answer 5

斯威夫特：

if UIImagePickerController.isSourceTypeAvailable(.Camera){

    //Your code goes here
    //For example you can print available media types:

    print(UIImagePickerController.availableMediaTypesForSourceType(.Camera))

    }

Answer 6

如果您需要知道设备是否有前置摄像头或后置摄像头，请使用以下命令：

isCameraAvailable = [UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceFront];

Answer 7

您可以使用发现会话 (Swift 5) 检查特定源类型的可用性：

let discovery = AVCaptureDevice.DiscoverySession.init(deviceTypes: [.builtInWideAngleCamera], mediaType: AVMediaType.video, position: .back)
let isWideAngleCameraSupported = !discovery.devices.isEmpty

Answer 8

检查相机是否可用（Swift）

if(!UIImagePickerController.isSourceTypeAvailable(UIImagePickerControllerSourceType.Camera))