How to access flutter assets from Java

问题

This code can be used to access flutter assets from Java:

String assetName = call.argument("asset");
String assetLookupKey = registrar.lookupKeyForAsset(assetName);
AssetFileDescriptor fd = registrar.context().getAssets().openFd(assetLookupKey);
player = new VideoPlayer(eventChannel, handle, fd, result);

However, how do I get registrar? I know FlutterActivity has this method:

registrarFor(String pluginKey)

But which key should I use? I'm not using any plugin, I'm trying to load the assets from my own app.

来源：https://stackoverflow.com/questions/65374762/how-to-access-flutter-assets-from-java