目标c-在iOS上已经拒绝用户访问相机后,是否可以要求用户访问相机?

我正在使用此代码,但不幸的是它不起作用。

用户拒绝相机访问后,我想让他们下一次尝试加载相机时再次获得许可(在这种情况下,这是使用相机视图的条形码扫描仪)。 我总是得到AVAuthorizationStatusDenied,然后granted总是自动返回NO,即使我再次在代码中要求它。

我的许多用户都通过电子邮件向我发送电子邮件,说“当我尝试进行条形码扫描时,我的屏幕是黑色的”,这是因为他们出于某种原因拒绝了摄像机的访问。 我希望能够再次提示他们,因为最有可能的否认是一个错误。

有没有办法做到这一点?

    AVAuthorizationStatus authStatus = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];
    if(authStatus == AVAuthorizationStatusAuthorized)
    {
        NSLog(@"%@", @"You have camera access");
    }
    else if(authStatus == AVAuthorizationStatusDenied)
    {
        NSLog(@"%@", @"Denied camera access");

        [AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted) {
            if(granted){
                NSLog(@"Granted access to %@", AVMediaTypeVideo);
            } else {
                NSLog(@"Not granted access to %@", AVMediaTypeVideo);
            }
        }];
    }
    else if(authStatus == AVAuthorizationStatusRestricted)
    {
        NSLog(@"%@", @"Restricted, normally won't happen");
    }
    else if(authStatus == AVAuthorizationStatusNotDetermined)
    {
        NSLog(@"%@", @"Camera access not determined. Ask for permission.");

        [AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted) {
            if(granted){
                NSLog(@"Granted access to %@", AVMediaTypeVideo);
            } else {
                NSLog(@"Not granted access to %@", AVMediaTypeVideo);
            }
        }];
    }
    else
    {
        NSLog(@"%@", @"Camera access unknown error.");
    }
Ethan Allen asked 2019-11-15T19:30:35Z
4个解决方案
86 votes

经过一番研究,看来您做不到我想要的。 这是我编写的替代方法,用于在Windows 8+上弹出对话框并自动打开“设置”应用程序。

一些注意事项:

  • 从iOS 10开始,您需要在Info.plist中指定NSCameraUsageDescription键,以便能够请求照相机访问,否则您的应用程序将在运行时崩溃。
  • 用户更改了您的应用程序的任何权限后,它将终止您的应用程序。 在用户点击“开始”按钮之前,进行相应的处理并保存所有需要的数据。
  • 在iOS 8和11之间的某个时间点,Apple不再需要用户触摸“设置”应用程序中的“隐私”单元来获取和更改“相机”设置。 您可能需要根据用户使用的iOS版本来更改有关“用户”在“设置”应用中应执行的操作的说明。 如果有人想在下面留下评论告诉我们更改了哪些确切的iOS版本,那就太好了。

斯威夫特4:

在视图控制器的顶部:

import AVFoundation

打开相机视图之前:

@IBAction func goToCamera()
{
    let status = AVCaptureDevice.authorizationStatus(for: AVMediaType.video)
    switch (status)
    {
    case .authorized:
        self.popCamera()

    case .notDetermined:
        AVCaptureDevice.requestAccess(for: AVMediaType.video) { (granted) in
            if (granted)
            {
                self.popCamera()
            }
            else
            {
                self.camDenied()
            }
        }

    case .denied:
        self.camDenied()

    case .restricted:
        let alert = UIAlertController(title: "Restricted",
                                      message: "You've been restricted from using the camera on this device. Without camera access this feature won't work. Please contact the device owner so they can give you access.",
                                      preferredStyle: .alert)

        let okAction = UIAlertAction(title: "OK", style: .default, handler: nil)
        alert.addAction(okAction)
        self.present(alert, animated: true, completion: nil)
    }
}

带有完成阻止的拒绝警报:

func camDenied()
{
    DispatchQueue.main.async
        {
            var alertText = "It looks like your privacy settings are preventing us from accessing your camera to do barcode scanning. You can fix this by doing the following:\n\n1. Close this app.\n\n2. Open the Settings app.\n\n3. Scroll to the bottom and select this app in the list.\n\n4. Turn the Camera on.\n\n5. Open this app and try again."

            var alertButton = "OK"
            var goAction = UIAlertAction(title: alertButton, style: .default, handler: nil)

            if UIApplication.shared.canOpenURL(URL(string: UIApplicationOpenSettingsURLString)!)
            {
                alertText = "It looks like your privacy settings are preventing us from accessing your camera to do barcode scanning. You can fix this by doing the following:\n\n1. Touch the Go button below to open the Settings app.\n\n2. Turn the Camera on.\n\n3. Open this app and try again."

                alertButton = "Go"

                goAction = UIAlertAction(title: alertButton, style: .default, handler: {(alert: UIAlertAction!) -> Void in
                    UIApplication.shared.open(URL(string: UIApplicationOpenSettingsURLString)!, options: [:], completionHandler: nil)
                })
            }

            let alert = UIAlertController(title: "Error", message: alertText, preferredStyle: .alert)
            alert.addAction(goAction)
            self.present(alert, animated: true, completion: nil)
    }
}

Objective-C的:

在视图控制器的顶部:

#import <AVFoundation/AVFoundation.h>

打开相机视图之前:

- (IBAction)goToCamera
{
    AVAuthorizationStatus authStatus = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];
    if(authStatus == AVAuthorizationStatusAuthorized)
    {
        [self popCamera];
    }
    else if(authStatus == AVAuthorizationStatusNotDetermined)
    {
        NSLog(@"%@", @"Camera access not determined. Ask for permission.");

        [AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted)
        {
            if(granted)
            {
                NSLog(@"Granted access to %@", AVMediaTypeVideo);
                [self popCamera];
            }
            else
            {
                NSLog(@"Not granted access to %@", AVMediaTypeVideo);
                [self camDenied];
            }
        }];
    }
    else if (authStatus == AVAuthorizationStatusRestricted)
    {
        // My own Helper class is used here to pop a dialog in one simple line.
        [Helper popAlertMessageWithTitle:@"Error" alertText:@"You've been restricted from using the camera on this device. Without camera access this feature won't work. Please contact the device owner so they can give you access."];
    }
    else
    {
        [self camDenied];
    }
}

拒绝警报:

- (void)camDenied
{
    NSLog(@"%@", @"Denied camera access");

    NSString *alertText;
    NSString *alertButton;

    BOOL canOpenSettings = (&UIApplicationOpenSettingsURLString != NULL);
    if (canOpenSettings)
    {
        alertText = @"It looks like your privacy settings are preventing us from accessing your camera to do barcode scanning. You can fix this by doing the following:\n\n1. Touch the Go button below to open the Settings app.\n\n2. Turn the Camera on.\n\n3. Open this app and try again.";

        alertButton = @"Go";
    }
    else
    {
        alertText = @"It looks like your privacy settings are preventing us from accessing your camera to do barcode scanning. You can fix this by doing the following:\n\n1. Close this app.\n\n2. Open the Settings app.\n\n3. Scroll to the bottom and select this app in the list.\n\n4. Turn the Camera on.\n\n5. Open this app and try again.";

        alertButton = @"OK";
    }

    UIAlertView *alert = [[UIAlertView alloc]
                          initWithTitle:@"Error"
                          message:alertText
                          delegate:self
                          cancelButtonTitle:alertButton
                          otherButtonTitles:nil];
    alert.tag = 3491832;
    [alert show];
}

委托UIAlertView:

- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex
{
    if (alertView.tag == 3491832)
    {
        BOOL canOpenSettings = (&UIApplicationOpenSettingsURLString != NULL);
        if (canOpenSettings)
            [[UIApplication sharedApplication] openURL:[NSURL URLWithString:UIApplicationOpenSettingsURLString]];
    }
}
Ethan Allen answered 2019-11-15T19:31:53Z
9 votes

一旦他们拒绝了摄像头访问权限,用户就可以在“设置”中授权您的应用使用摄像头。 根据设计,您不能在自己的代码中覆盖它。

您可以使用以下示例代码检测到这种情况,然后向用户说明如何解决此问题:iOS 7 UIImagePickerController Camera No Image

NSString *mediaType = AVMediaTypeVideo; // Or AVMediaTypeAudio

AVAuthorizationStatus authStatus = [AVCaptureDevice authorizationStatusForMediaType:mediaType];

// The user has explicitly denied permission for media capture.
else if(authStatus == AVAuthorizationStatusDenied){
    NSLog(@"Denied");
}
StilesCrisis answered 2019-11-15T19:32:24Z
2 votes

对于Swift 3.0

这将引导用户进行更改权限的设置。

func checkCameraAuthorise() -> Bool {
    let status = AVCaptureDevice.authorizationStatus(forMediaType: AVMediaTypeVideo)
    if status == .restricted || status == .denied {
        let dialog = ZAlertView(title: "", message: "Please allow access to the camera in the device's Settings -> Privacy -> Camera", isOkButtonLeft: false, okButtonText: "OK", cancelButtonText: "Cancel", okButtonHandler:
            { _ -> Void in UIApplication.shared.openURL(URL(string: UIApplicationOpenSettingsURLString)!)}, cancelButtonHandler: { alertView in alertView.dismissAlertView() })
        dialog.show()
        return false
    }
    return true
}
ak_ninan answered 2019-11-15T19:32:50Z
0 votes

相机访问和照片库访问的完整代码

import AVFoundation

要处理相机动作,请使用以下代码:方法调用

func openCameraOrLibrary(){
    let imagePicker = UIImagePickerController()
    let alertController : UIAlertController = UIAlertController(title: "Select Camera or Photo Library".localized, message: "", preferredStyle: .actionSheet)
    let cameraAction : UIAlertAction = UIAlertAction(title: "Camera".localized, style: .default, handler: {(cameraAction) in

        if UIImagePickerController.isSourceTypeAvailable(UIImagePickerControllerSourceType.camera) == true {
            if self.isCamAccessDenied() == false { **//Calling cam access method here**
                imagePicker.sourceType = .camera
                imagePicker.delegate = self
                self.present(imagePicker, animated: true, completion: nil)
            }

        }else{
            self.present(self.showAlert(Title: "", Message: "Camera is not available on this Device or accesibility has been revoked!".localized), animated: true, completion: nil)
            self.showTabbar()

        }

    })

    let libraryAction : UIAlertAction = UIAlertAction(title: "Photo Library", style: .default, handler: {(libraryAction) in

        if UIImagePickerController.isSourceTypeAvailable(UIImagePickerControllerSourceType.photoLibrary) == true {

            imagePicker.sourceType = .photoLibrary
            imagePicker.delegate = self
            self.present(imagePicker, animated: true, completion: nil)

        }else{
            self.showTabbar()
            self.present(self.showAlert(Title: "", Message: "Photo Library is not available on this Device or accesibility has been revoked!".localized), animated: true, completion: nil)
        }
    })

    let cancelAction : UIAlertAction = UIAlertAction(title: "Cancel".localized, style: .cancel , handler: {(cancelActn) in
        self.showTabbar()
    })

    alertController.addAction(cameraAction)

    alertController.addAction(libraryAction)

    alertController.addAction(cancelAction)

    alertController.popoverPresentationController?.sourceView = view
    alertController.popoverPresentationController?.sourceRect = view.frame

    self.present(alertController, animated: true, completion: nil)
    self.hideTabbar()

}

处理相机访问功能的方法

func isCamAccessDenied()-> Bool
{
    let status = AVCaptureDevice.authorizationStatus(for: AVMediaType.video)
    if status == .restricted || status == .denied {
    DispatchQueue.main.async
        {
            var alertText = "It looks like your privacy settings are preventing us from accessing your camera to do barcode scanning. You can fix this by doing the following:\n\n1. Close this app.\n\n2. Open the Settings app.\n\n3. Scroll to the bottom and select this app in the list.\n\n4. Turn the Camera on.\n\n5. Open this app and try again."

            var alertButton = "OK"
            var goAction = UIAlertAction(title: alertButton, style: .default, handler: nil)

            if UIApplication.shared.canOpenURL(URL(string: UIApplicationOpenSettingsURLString)!)
            {
                alertText = "It looks like your privacy settings are preventing us from accessing your camera to do barcode scanning. You can fix this by doing the following:\n\n1. Touch the Go button below to open the Settings app.\n\n2. Turn the Camera on.\n\n3. Open this app and try again."

                alertButton = "OK"

                goAction = UIAlertAction(title: alertButton, style: .default, handler: {(alert: UIAlertAction!) -> Void in
                    UIApplication.shared.open(URL(string: UIApplicationOpenSettingsURLString)!, options: [:], completionHandler: nil)
                })
            }

            let alert = UIAlertController(title: "Error", message: alertText, preferredStyle: .alert)
            alert.addAction(goAction)
            self.present(alert, animated: true, completion: nil)
        }
        return true
    }
    return false
}
Alok answered 2019-11-15T19:33:26Z
translate from https://stackoverflow.com:/questions/26070393/is-there-a-way-to-ask-user-for-camera-access-after-they-have-already-denied-it-o