MPMediaPickerControllerDelegate 权限检查 Swift

Question

我的项目中有以下代码通过“MPMediaPickerControllerDelegate”选择音频文件。运行以下代码时，第一次提示用户授予权限。如果用户拒绝加载，选择器将静默失败。

如果用户一开始拒绝后返回，有没有办法提示用户授予权限？

我想知道这是否是一个错误。有什么方法可以检测 MPMediaPickerControllerDelegate 的权限，以便我们决定是否显示音频。

下面是我的代码：

let myMediaPickerVC = MPMediaPickerController(mediaTypes: MPMediaType.anyAudio)
myMediaPickerVC.allowsPickingMultipleItems = false
myMediaPickerVC.delegate = self
present(myMediaPickerVC, animated: true, completion: nil)

Answer 1

您必须首先检查授权权限，然后如果 authorizationStatus 权限为authorized，则运行您的代码。如果不是notDetermined，请请求许可。如果是denied，则显示警报，要求用户转到设置并启用此权限。

MPMediaLibrary.requestAuthorization({(newPermissionStatus: MPMediaLibraryAuthorizationStatus) in  
    // This code will be called after the user allows or denies your app permission.  
    switch (permissionStatus) {  
        case MPMediaLibraryAuthorizationStatus.authorized:  
             print("permission status is authorized")  
        case MPMediaLibraryAuthorizationStatus.notDetermined:  
             print("permission status is not determined")  
          MPMediaLibrary.requestAuthorization(MPMediaLibraryAuthorizationStatus -> permissionStatus)  
        case MPMediaLibraryAuthorizationStatus.denied:  
             print("permission status is denied")  
        case MPMediaLibraryAuthorizationStatus.restricted:  
             print("permission status is restricted")  
    }  
})