Use Retrofit methods more expressive way

Question

I want to make void enqueue(Callback<T> callback); method invocation code block more expressive, Here is what I have an usually

request.enqueue(object : Callback<MyModel> {
      override fun onFailure(call: Call<MyModel>?, t: Throwable?) {
           //
      }

      override fun onResponse(call: Call<MyModel>?, response: Response<MyModel>?) {
           //
      }
 })

And what I want and mean is that, to change this code blocks more cleaner way and remove those override, object, Callback keywords and do something like that:

request.enqueue({throwable, response -> })

I think it could be improved somehow using extensions and higher-order functions. Does anyone know how it can be done?

Answer 1

this is how i do it with extension function and a class

fun<T> Call<T>.enqueue(callback: CallBackKt<T>.() -> Unit) {
    val callBackKt = CallBackKt<T>()
    callback.invoke(callBackKt)
    this.enqueue(callBackKt)
}

class CallBackKt<T>: Callback<T> {

    var onResponse: ((Response<T>) -> Unit)? = null
    var onFailure: ((t: Throwable?) -> Unit)? = null

    override fun onFailure(call: Call<T>, t: Throwable) {
        onFailure?.invoke(t)
    }

    override fun onResponse(call: Call<T>, response: Response<T>) {
        onResponse?.invoke(response)
    }

}

then you can use it like this

request.enqueue {

    onResponse = {
        // do
    }

    onFailure = {
        // do
    }

}