如何檢測相機是否受用戶限制

Question

我正在使用啓動相機的按鈕執行ios應用程序。

我想啓用/禁用按鈕，如果設備有一個相機可用或不。

我想檢測設備是否有攝像頭，也有設備有攝像頭但受限制（使用this），因此您無法使用它。

如何檢測這兩個選項？

感謝

Answer 1

如在別處所述，檢查AVAuthorizationStatus實際上並不會告訴你，如果它的限制，儘管在枚舉中存在「受限制」的值。 相反，我發現，檢查是否被啓用是有幫助的：

BOOL isCameraAvailable = [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]; 

如果isCameraAvailable是NO那麼用戶在限制最有可能禁用相機。見Detect existence of camera in iPhone app?

Answer 2

的用戶第一次嘗試使用相機在iOS 6上，他/她會自動請求批准。您不必添加額外的代碼（在authorisationstatus爲ALAuthorizationStatusNotDetermined之前）。

所以如果用戶第一次否認你不能再問。

您可以使用ALAssetsLibrary來檢查這一點。 檢查此解決方案的答案： ask-permission-to-access-camera

希望它可以幫助你。

Answer 3

檢查應用程序使用以下代碼段中的攝像頭權限狀態。

if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) 
{ 
    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){ 
      NSLog(@"Granted access"); 
      } else { 
      NSLog(@"Not granted access"); 
      } 
     }]; 
    } 
} 

Answer 4

檢查攝像機是否受限制AVAuthorizationStatus是不夠的。正如文檔中所述：

此狀態通常不可見 - 用於發現設備的AVCaptureDevice類方法不返回用戶被禁止訪問的設備。

因此，對於合適的檢查，你需要創建一些捕獲裝置，例如，像我一樣：

AVAuthorizationStatus authStatus = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo]; 
if (authStatus == AVAuthorizationStatusAuthorized) { 
    BOOL atLeastOne = NO; 
    NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo]; 
    for (AVCaptureDevice *device in devices) { 
     if (device) { 
      atLeastOne = YES; 
     } 
    } 
    if (!atLeastOne) { 
     authStatus = AVAuthorizationStatusRestricted; 
    } 
} 

Answer 5

SWIFT

，以決定是否相機按鈕甚至應該允許（或隱藏）您應檢查：

if UIImagePickerController.isSourceTypeAvailable(.Camera){ } 

但後來我會檢查，看看是否用戶允許訪問攝像機，如蘋果在其PhotoPicker示例中所示（PhotoPicker example Objective-C）：

*請注意你必須導入AVFoundation

let authStatus = AVCaptureDevice.authorizationStatus(forMediaType: AVMediaTypeVideo) 

if authStatus == AVAuthorizationStatus.denied { 
    // Denied access to camera 
    // Explain that we need camera access and how to change it. 
    let dialog = UIAlertController(title: "Unable to access the Camera", message: "To enable access, go to Settings > Privacy > Camera and turn on Camera access for this app.", preferredStyle: UIAlertControllerStyle.alert) 

    let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: nil) 

    dialog.addAction(okAction) 
    self.present(dialog, animated:true, completion:nil) 

} else if authStatus == AVAuthorizationStatus.notDetermined {  // The user has not yet been presented with the option to grant access to the camera hardware. 
    // Ask for it. 
    AVCaptureDevice.requestAccess(forMediaType: AVMediaTypeVideo, completionHandler: { (grantd) in 
    // If access was denied, we do not set the setup error message since access was just denied. 
     if grantd { 
     // Allowed access to camera, go ahead and present the UIImagePickerController. 
      self.showImagePickerForSourceType(sourceType: UIImagePickerControllerSourceType.camera) 
     } 
    }) 
} else { 

    // Allowed access to camera, go ahead and present the UIImagePickerController. 
    self.showImagePickerForSourceType(sourceType: UIImagePickerControllerSourceType.camera) 

} 

func showImagePickerForSourceType(sourceType: UIImagePickerControllerSourceType) { 

    let myPickerController = UIImagePickerController() 
    myPickerController.delegate = self; 
    myPickerController.sourceType = sourceType 
    self.present(myPickerController, animated: true, completion: nil) 
}