[question] what is the purpose of ViewManagerDelegate

[vonovak]

When migrating a component to Fabric, there is a step documented here https://reactnative.dev/docs/next/the-new-architecture/pillars-fabric-components#centeredtextmanagerjava which adds the following

    private final ViewManagerDelegate<CenteredText> mDelegate;

    public CenteredTextManager(ReactApplicationContext context) {
        mDelegate = new RTNCenteredTextManagerDelegate<>(this);
    }

    @Nullable
    @Override
    protected ViewManagerDelegate<CenteredText> getDelegate() {
        return mDelegate;
    }

I'd like to know what the purpose of the delegate is. Is it mandatory?

Implementing the RTNCenteredTextManagerInterface does not enforce the presence of getDelegate() and I'm wondering what it's purpose is, because all the delegate does is that is ends up calling the methods on the ViewManager. Is it for imperative command dispatching?

Thank you! :)

[cortinico]

Hi @vonovak,
Happy to respond,

Implementing the RTNCenteredTextManagerInterface does not enforce the presence of getDelegate()

You're right in saying that the generated Interface does not require you to pass a delegate.
On the other hand, your RTNCenteredTextManager needs to extend one of the ViewManager classes (i.e. SimpleViewManager or BaseViewManager or just ViewManager).

The ViewManager class however has a getDelegate() method which can be used to pass a ViewManagerDelegate. This class is conveniently generated for you by the codegen, and will take care of all the wiring for the setProperty and receiveCommand.

So in theory, you could avoid setting it, but your view won't work unless you wire all the setProperty manually. Plus the BaseViewManagerDelegate class which we extend from when we generate your delegate, has all the logic to handle common view props such as accessibility props and so on.