Creating Models From ViewHolders works in Java. Not in Kotlin

I’ve been doing the following when creating Models from viewholders in java

@EpoxyModelClass(layout = R.layout.da_thing)
public abstract class MyModel extends EpoxyModelWithHolder<MyModel.MyHolder> {
    @EpoxyAttribute
    EmailItem emailItem;


    @Override
    public void bind(YourViewHolder holder) {
        super.bind(holder);
        holder.bindingTime(emailItem);
    }

    static class MyHolder extends BaseEpoxyHolder {

        @BindView(R.id.text) TextView textView;

        public void bindingTime(EmailItem emailItem) {
            textView(your_info_needed_for_model+"");

        }
    }
}

This works well, but when I convert to Kotlin (kotlin noob here) I get the following. It seems like the fault is mostly on Butterknife. The question is… since using Kotlin I do not use Butterknife anymore.

Essentially I got this though.

@EpoxyModelClass(layout = R.layout.da_thing)
abstract class MyModel : EpoxyModelWithHolder<MyModel.MyHolder>() {
    @EpoxyAttribute
    var emailItem: EmailItem = EmailItem()


    override fun bind(holder: MyHolder?) {
        super.bind(holder)
        holder!!.bindTo(emailItem)
    }

    class MyHolder : BaseEpoxyHolder() {

        @BindView(R.id.text) var textView: TextView? = null

        fun bindTo(emailItem: EmailItem) {
            textView?.setText("asdf")
        }
    }
}

It’d be great to get rid of butterknife in this case. Thoughts @elihart ?

[elihart]

changing from annotationProcessor to kapt is the correct fix. I’m guessing you just needed to do a clean build to force it to recompile

[elihart]

@ColtonIdle Yes, you can shorten it to something like this

@EpoxyModelClass(layout = R.layout.view_holder_page_header)
abstract class SampleKotlinModelWithHolder : EpoxyModelWithHolder<Holder>() {

    @EpoxyAttribute lateinit var title: String
    @EpoxyAttribute lateinit var imageUrl: Uri

    override fun bind(holder: Holder) {
        holder.imageView.setImageURI(imageUrl)
        holder.titleView.text = title
    }
}

class Holder : KotlinHolder() {
    val titleView by bind<TextView>(R.id.title)
    val imageView by bind<ImageView>(R.id.image)
}

I took some time to write up kotlin samples in a new wiki page https://github.com/airbnb/epoxy/wiki/Kotlin-Model-Examples

I also played around with imagining a completely new kotlin pattern. I think this has potential, but could use some iteration, and possibly some changes to the processor to support it officially.

data class SampleKotlinModel(
    val title: String,
    val imageUrl: Uri
) : KotlinModel(R.layout.view_holder_page_header) {

    val titleView by bind<TextView>(R.id.title)
    val imageView by bind<ImageView>(R.id.image)

    override fun bind() {
        titleView.text = title
        imageView.setImageURI(imageUrl)
    }
}