How to call backend from a Recyclerview.ViewHolder

Question

I have a recyclerview and a correspoinding viewholder to hold individual item. The viewholder has button which onClick needs to communicate with backend. I have a repository class that talks with backend present as the part of my activity.

class QuestionDetailsActivity : AppCompatActivity() {

    @Inject
    lateinit var myRepository: MyRepository
    // OnCreate other functionality etc.
}

Below is how my viewholder layout looks like.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<Button
    android:id="@+id/updateBackendButton"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:text="Update"/>
<View
    android:id="@+id/textView"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_weight="2"
    android:text="Text view"/>
<Button
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:text="Right Button"/>
</LinearLayout>

my viewholder class as below

class MyViewHolder(view: View) : RecyclerView.ViewHolder(view) {

 private val button = view.updateBackendButton

 init {
   updateBackendButton.setOnClickListener {
       // I would like to call backend here with textView data
   }
 }

 companion object {
        fun create(parent: ViewGroup): MyViewHolder {
            val view = LayoutInflater.from(parent.context)
                    .inflate(R.layout.my_item, parent, false)
            return MyViewHolder(view)
        }
    }
}

How do I make the MyRepository available inside the viewHolder, shall I also inject that inside the viewholder or accept a method in my ViewHolder as an arugment from activity and invoke that method inside the viewholder with the argument?

Answer 1

I would create an interface to handle the onClick, and implement that interface on the Activity. There you have access to the Repo with your injecton.

updateBackendButton.setOnClickListener {
    listener.onUpdateBackendButton()
}

The listener could be like follows:

interface YourListener {
    fun onUpdateBackendButton()
}