在iOS 8中显示相机权限对话框

Question

当我的应用程序第一次尝试在iOS 8上访问摄像头时,会向用户显示摄像头权限对话框,非常类似于iOS 7中用于麦克风访问的麦克风.

在iOS 7中,可以事先调用麦克风权限对话框,并查看是否已授予权限(例如,请参阅此问题).是否有类似的方法来调用iOS 8中的相机权限对话框？可以将对话组合用于麦克风和摄像机访问权限吗？

Answer 1

以下是我们最终使用的方法:

if ([AVCaptureDevice respondsToSelector:@selector(requestAccessForMediaType: completionHandler:)]) {
    [AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted) {
        // Will get here on both iOS 7 & 8 even though camera permissions weren't required 
        // until iOS 8. So for iOS 7 permission will always be granted.
        if (granted) {
            // Permission has been granted. Use dispatch_async for any UI updating
            // code because this block may be executed in a thread.
            dispatch_async(dispatch_get_main_queue(), ^{
                [self doStuff];
            });                
        } else {
            // Permission has been denied.
        }
    }];
} else {
    // We are on iOS <= 6. Just do what we need to do.
    [self doStuff];
}

Answer 2

我遇到类似的问题,如果用户拒绝了摄像头的访问时,他们第一次提示,按下按钮,采取在相机模式下拍摄导致黑屏易如反掌.

但是我想检测用户已拒绝访问,并促使他们必须被打开,但我无法找到任何函数来检查当前用户访问摄像机,是有这样的功能？

编辑:以下检查将在IOS 8中通知您关于相机访问:

#import <AVFoundation/AVFoundation.h>

AVAuthorizationStatus status = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];

    if(status == AVAuthorizationStatusAuthorized) { // authorized

    }
    else if(status == AVAuthorizationStatusDenied){ // denied

    }
    else if(status == AVAuthorizationStatusRestricted){ // restricted


    }
    else if(status == AVAuthorizationStatusNotDetermined){ // not determined

        [AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted) {
            if(granted){ // Access has been granted ..do something

            } else { // Access denied ..do something

            }
        }];
    }

此信息可在以下问题中找到(如何在iOS8中以编程方式知道该应用程序是否具有摄像头访问权限):

Answer 3

这是我的Swift解决方案(iOS 8),我需要相机进行QR扫描,所以必须提示它的使用.

这提供了

1. 鼓励用户在默认允许摄像头访问问题之前选择允许

2. 如果用户拒绝第一个请求,则可以轻松访问设置.

为了让它运行,请在ViewDidAppear /或ViewDidLoad等中调用相机.我需要使用viewDidAppear,以便设置我的自定义相机视图约束.

func checkCamera() {
    let authStatus = AVCaptureDevice.authorizationStatus(forMediaType: AVMediaTypeVideo)
    switch authStatus {
    case .authorized: break // Do your stuff here i.e. allowScanning()
    case .denied: alertToEncourageCameraAccessInitially()
    case .notDetermined: alertPromptToAllowCameraAccessViaSetting()
    default: alertToEncourageCameraAccessInitially()
    }
}

func alertToEncourageCameraAccessInitially() {
    let alert = UIAlertController(
        title: "IMPORTANT",
        message: "Camera access required for QR Scanning",
        preferredStyle: UIAlertControllerStyle.alert
    )
    alert.addAction(UIAlertAction(title: "Cancel", style: .default, handler: nil))
    alert.addAction(UIAlertAction(title: "Allow Camera", style: .cancel, handler: { (alert) -> Void in
        UIApplication.shared.openURL(URL(string: UIApplicationOpenSettingsURLString)!)
    }))
    present(alert, animated: true, completion: nil)
}

func alertPromptToAllowCameraAccessViaSetting() {

    let alert = UIAlertController(
        title: "IMPORTANT",
        message: "Please allow camera access for QR Scanning",
        preferredStyle: UIAlertControllerStyle.alert
    )
    alert.addAction(UIAlertAction(title: "Dismiss", style: .cancel) { alert in
        if AVCaptureDevice.devices(withMediaType: AVMediaTypeVideo).count > 0 {
            AVCaptureDevice.requestAccess(forMediaType: AVMediaTypeVideo) { granted in
                DispatchQueue.main.async() {
                    self.checkCamera() } }
        }
        }
    )
    present(alert, animated: true, completion: nil)
}

感谢上面的jamix用于使用dispatch_async的提示 - 使响应显示新设置的相机功能更快.

对不起混合的尾随封闭..想试试看.

Answer 4

没有任何答案似乎检查麦克风和相机权限.我们的代码会检查授予摄像机权限但麦克风访问被拒绝的情况.

由于我们是Swift的新手,因此粗糙嵌套的闭包和if语句不太可能是最佳的.请分享改进代码的建议!但至少它在测试中起作用.

    AVCaptureDevice.requestAccessForMediaType(AVMediaTypeVideo, completionHandler: { (videoGranted: Bool) -> Void in
        if (videoGranted) {
            AVCaptureDevice.requestAccessForMediaType(AVMediaTypeAudio, completionHandler: { (audioGranted: Bool) -> Void in
                if (audioGranted) {
                    dispatch_async(dispatch_get_main_queue()) {
                        // Both video & audio granted
                    }
                } else {
                    // Rejected audio
                }
            })
        } else {
            // Rejected video
        }
    })

Answer 5

• Swift 3.0解决方案

  导入AVFoundation

注意:在Info.plist上添加隐私 - 相机使用说明密钥

// MARK:相机处理

        func callCamera(){
            let myPickerController = UIImagePickerController()
            myPickerController.delegate = self;
            myPickerController.sourceType = UIImagePickerControllerSourceType.camera

            self.present(myPickerController, animated: true, completion: nil)
            NSLog("Camera");
        }
        func checkCamera() {
            let authStatus = AVCaptureDevice.authorizationStatus(forMediaType: AVMediaTypeVideo)
            switch authStatus {
            case .authorized: callCamera() // Do your stuff here i.e. callCameraMethod()
            case .denied: alertToEncourageCameraAccessInitially()
            case .notDetermined: alertPromptToAllowCameraAccessViaSetting()
            default: alertToEncourageCameraAccessInitially()
            }
        }

        func alertToEncourageCameraAccessInitially() {
            let alert = UIAlertController(
                title: "IMPORTANT",
                message: "Camera access required for capturing photos!",
                preferredStyle: UIAlertControllerStyle.alert
            )
            alert.addAction(UIAlertAction(title: "Cancel", style: .default, handler: nil))
            alert.addAction(UIAlertAction(title: "Allow Camera", style: .cancel, handler: { (alert) -> Void in
                UIApplication.shared.openURL(URL(string: UIApplicationOpenSettingsURLString)!)
            }))
            present(alert, animated: true, completion: nil)
        }

        func alertPromptToAllowCameraAccessViaSetting() {

            let alert = UIAlertController(
                title: "IMPORTANT",
                message: "Camera access required for capturing photos!",
                preferredStyle: UIAlertControllerStyle.alert
            )
            alert.addAction(UIAlertAction(title: "Dismiss", style: .cancel) { alert in
                if AVCaptureDevice.devices(withMediaType: AVMediaTypeVideo).count > 0 {
                    AVCaptureDevice.requestAccess(forMediaType: AVMediaTypeVideo) { granted in
                        DispatchQueue.main.async() {
                            self.checkCamera() } }
                }
                }
            )
            present(alert, animated: true, completion: nil)
        }

Answer 6

对于 Swift 3，您可以将其添加到您viewWillAppear的第一个视图控制器的方法中：

首先导入AVFoundation框架

import AVFoundation

然后：

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    let authorizationStatus = AVCaptureDevice.authorizationStatus(forMediaType: AVMediaTypeVideo)

    switch authorizationStatus {
    case .notDetermined:
        AVCaptureDevice.requestAccess(forMediaType: AVMediaTypeVideo) { granted in
            if granted {
                print("access granted")
            }
            else {
                print("access denied")
            }
        }
    case .authorized:
        print("Access authorized")
    case .denied, .restricted:
        print("restricted")

    }
}

不要忘记Privacy - Camera Usage Description在您的Info.plist