Android 14与Xamarin项目中USB权限请求失败的解决

在Android 14的Xamarin项目中，使用USBSerialForAndroid库获取USB设备权限时，遇到了PendingIntent相关的兼容性问题，以下是问题及解决过程：

最初实现的代码 #

public static Task<bool> RequestPermissionAsync(this UsbManager manager, UsbDevice device, Context context)
{
    var completionSource = new TaskCompletionSource<bool>();

    var usbPermissionReceiver = new UsbPermissionReceiver(completionSource);

    if (Build.VERSION.SdkInt >= BuildVersionCodes.Tiramisu)
        context.RegisterReceiver(usbPermissionReceiver, new IntentFilter(ACTION_USB_PERMISSION), (ActivityFlags)ReceiverFlags.Exported);
    else
        context.RegisterReceiver(usbPermissionReceiver, new IntentFilter(ACTION_USB_PERMISSION));
    

    // Targeting S+ (version 31 and above) requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified when creating a PendingIntent.
    PendingIntentFlags pendingIntentFlags = Build.VERSION.SdkInt >= BuildVersionCodes.S && Build.VERSION.SdkInt < BuildVersionCodes.Tiramisu ? PendingIntentFlags.Mutable  : 0;

    var intent = PendingIntent.GetBroadcast(context, 0, new Intent(ACTION_USB_PERMISSION), pendingIntentFlags);

    manager.RequestPermission(device, intent);  

    return completionSource.Task;
}

遇到的错误 #

当设置PendingIntentFlags为Mutable时，触发以下错误：

Targeting U+ (version 34 and above) disallows creating or retrieving a PendingIntent with FLAG_MUTABLE, an implicit Intent within and without FLAG_NO_CREATE and FLAG_ALLOW_UNSAFE_IMPLICIT_INTENT for security reasons. To retrieve an already existing PendingIntent, use FLAG_NO_CREATE, however, to create a new PendingIntent with an implicit Intent use FLAG_IMMUTABLE.

若改为Immutable，则无法正常获取USB设备权限。

解决后的代码 #

通过为Intent指定包名，解决了权限获取问题，最终代码如下：

public static Task<bool> RequestPermissionAsync_Another(this UsbManager manager, UsbDevice device, Context context)
{
    TaskCompletionSource<bool> taskCompletionSource = new TaskCompletionSource<bool>();
    UsbPermissionReceiver receiver = new UsbPermissionReceiver(taskCompletionSource);
    if (Build.VERSION.SdkInt >= BuildVersionCodes.Tiramisu)
        context.RegisterReceiver(receiver, new IntentFilter(ACTION_USB_PERMISSION), ReceiverFlags.Exported);
    else
        context.RegisterReceiver(receiver, new IntentFilter(ACTION_USB_PERMISSION));

    Intent intent = new Intent(ACTION_USB_PERMISSION);
    intent.SetPackage(context.PackageName);

    PendingIntent broadcast = PendingIntent.GetBroadcast(context, 0, intent, PendingIntentFlags.Mutable);
    manager.RequestPermission(device, broadcast);
    return taskCompletionSource.Task;
}

内容的提问来源于stack exchange，提问作者007_programmer