iOS摄像头授权-状态错误

Question

我使用以下代码检查并请求相机的授权。问题如下。以下情况会导致错误的授权状态：

1. 用户首次拒绝授权
2. 终止应用程序
3. 重新启动应用程序
4. 离开应用程序，在设置应用程序中授予相机授权
5. 返回应用程序

[AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo]将返回AVAuthorizationStatusDeclined（如上所述授权）。

在终止和重新启动后，会产生AVAuthorizationStatusAuthorized。在这种情况下，用户继续设置并拒绝相机访问，结果将保持为AVAuthorizationStatusAuthorized，直到下一次重新启动。

你知道我错过了什么吗？

- (void) popCamera {
    UIImagePickerController *picker = [[UIImagePickerController alloc] init];
    picker.delegate = self;
    //picker.allowsEditing = YES;
    #if !(TARGET_IPHONE_SIMULATOR)
    picker.sourceType = UIImagePickerControllerSourceTypeCamera;
    picker.cameraDevice = UIImagePickerControllerCameraDeviceFront;
    #endif
    self.view.translatesAutoresizingMaskIntoConstraints = YES;
    [self presentViewController:picker animated:YES completion:NULL];
}
- (void)camDenied
{
    NSLog(@"%@", @"Denied camera access");
    NSString *alertText;
    NSString *alertButton;
    BOOL canOpenSettings = (&UIApplicationOpenSettingsURLString != NULL);
    if (canOpenSettings)
    {
        alertText = LSS(@"DeniedCamera1");
        SDCAlertView *alert = [[SDCAlertView alloc]
                              initWithTitle:LSS(@"DeniedCameraTitle")
                              message:alertText
                              delegate:self
                              cancelButtonTitle:LSS(@"Cancel")
                              otherButtonTitles:LSS(@"Goto"), nil];
        alert.tag = 3491832;
        [alert show];
    }
    else
    {
        alertText = LSS(@"DeniedCamera2");
        SDCAlertView *alert = [[SDCAlertView alloc]
                              initWithTitle:LSS(@"DeniedCameraTitle")
                              message:alertText
                              delegate:self
                              cancelButtonTitle:LSS(@"Cancel")
                              otherButtonTitles:nil];
        alert.tag = 3491832;
        [alert show];
    }
}
- (IBAction) onTakePhoto:(id)sender {
    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)
             {
                 [self popCamera];
             }
             else
             {
                 [self camDenied];
             }
         }];
    }
    else if (authStatus == AVAuthorizationStatusRestricted)
    {
        SDCAlertView *alert = [[SDCAlertView alloc]
                              initWithTitle:LSS(@"RestrictCameraTitle")
                              message:LSS(@"RestrictCamera")
                              delegate:self
                              cancelButtonTitle:LSS(@"OK")
                              otherButtonTitles:nil];
    }
    else
    {
        [self camDenied];
    }
    }

原始代码的来源：在iOS 8上拒绝用户访问相机后，有没有办法要求用户访问相机？

Answer 1

这似乎是预期的行为。如果苹果希望你在运行时对授权更改做出反应，会有一个通知告诉你它已经更改。

但目前还没有这样的通知（据我所见）。您只需调用+authorizationStatusForMediaType:，它就会返回最终状态（如拒绝或授权），或者返回AVAuthorizationStatusNotDetermined，告诉您需要通过requestAccessForMediaType:completionHandler:请求授权。

不幸的是，这不是一个权威的答案；我只是在这里得出结论和猜测。你可能想在苹果的开发者论坛上提问，并希望从苹果工程师那里得到答案。