我正在使用此代码，但遗憾的是它不起作用。
在用户拒绝摄像头访问后，我想让他们在下次尝试加载时再次使用摄像头（在这种情况下，它是使用摄像头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，即使我在代码中再次要求它。
我的许多用户都在给我发电子邮件说“当我尝试条形码扫描时我的屏幕是黑色的”，这是因为他们因某些原因拒绝了相机访问。我希望能够再次提示他们，因为很可能拒绝是错误的。
有可能这样做吗？
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.");
}
答案 0 :(得分：83)
经过一番研究，看起来你不能做我想做的事。如果在iOS 8 +上，我编码弹出对话框并自动打开“设置”应用程序。
一些注意事项：
NSCameraUsageDescription密钥以便能够请求摄像头访问，否则您的应用程序将在运行时崩溃。Swift 4：
在视图控制器的顶部：
import AVFoundation
在打开相机视图之前：
@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)
}
}
完成阻止拒绝提醒：
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)
}
}
<强>目标-C：
在视图控制器的顶部：
#import <AVFoundation/AVFoundation.h>
在打开相机视图之前：
- (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];
}
}
拒绝提醒：
- (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];
}
委托调用UIAlertView：
- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex
{
if (alertView.tag == 3491832)
{
BOOL canOpenSettings = (&UIApplicationOpenSettingsURLString != NULL);
if (canOpenSettings)
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:UIApplicationOpenSettingsURLString]];
}
}
答案 1 :(得分：9)
一旦他们拒绝了相机访问权限，用户就可以在“设置”中为您的应用授权使用相机。按照设计，您无法在自己的代码中覆盖它。
您可以使用以下示例代码检测此案例，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");
}
答案 2 :(得分：1)
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
}
答案 3 :(得分：0)
访问照相机和照片库的完整代码
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()
}
处理摄像头访问功能的方法
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
}