有没有办法让用户在iOS上拒绝后才能访问相机？ [英] Is there a way to ask user for Camera access after they have already denied it on iOS?
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问题描述
我正在使用此代码，但遗憾的是它不起作用。
I am using this code, but unfortunately it doesn't work.
用户拒绝摄像头访问后，我想要求他们允许使用下次他们尝试加载时再次使用相机（在这种情况下，它是使用相机视图的条形码扫描仪）。我总是得到 AVAuthorizationStatusDenied 然后被授予总是自动返回否即使我在代码中再次要求它。
After a user has denied camera access, I want to ask them for permission to use the camera again the next time they try to load it (in this case it's a barcode scanner using the camera view). I always get AVAuthorizationStatusDenied and then granted always automatically returns NO even though I ask for it again in code.
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由于某种原因，他们拒绝摄像头访问。我希望能够再次提示他们，因为很可能拒绝是这样。
Many of my users are e-mailing me saying "my screen is black when I try to barcode scan" and it's because they have denied camera access for some reason. I want to be able to prompt them again because most likely the denial was a mistake.
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.");
}
推荐答案
经过一番研究后看起来像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的替代方案。
After some research it looks like you can't do what I'd like. Here is the alternative that I coded to pop a dialog and open the Settings app automatically if on iOS 8+.
一些注意事项：
- 从iOS 10开始，您需要在Info.plist中指定
NSCameraUsageDescription键才能要求相机访问，否则您的应用程序将在运行时崩溃。 - 一旦用户更改了您的应用程序的任何权限，它将终止您的应用程序。在用户点击开始按钮之前，请相应处理并保存所有必需的数据。
- 在iOS 8和11之间的某个时刻，Apple不再要求用户触摸中的隐私单元格。设置应用以获取和更改相机设置。您可能希望根据用户使用的iOS版本更改用户在设置应用中应执行的操作的说明。如果有人想在下面发表评论告诉我们所有改变的iOS版本，那就太棒了。
- Since iOS 10 you need to specify
NSCameraUsageDescriptionkey in your Info.plist to be able ask for camera access, otherwise your app will crash at runtime. - Once the user changes any permissions for your app, it will kill your app. Handle accordingly and save any needed data before the user hits that "Go" button.
- At some point between iOS 8 and 11, Apple no longer required the user to touch the Privacy cell in the Setting apps in order to get to and change the Camera settings. You may want to change your instructions on what the user is supposed to do in the Settings app based on what iOS version they are using. If someone wants to leave a comment below telling us all what exact iOS version that changed in, that would be awesome.
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)
}
}
完成块拒绝提醒：
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)
}
}
Objective-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：
Delegate call for the UIAlertView:
- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex
{
if (alertView.tag == 3491832)
{
BOOL canOpenSettings = (&UIApplicationOpenSettingsURLString != NULL);
if (canOpenSettings)
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:UIApplicationOpenSettingsURLString]];
}
}
这篇关于有没有办法让用户在iOS上拒绝后才能访问相机？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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