Replace java generic interface in Kotlin for data binding

I got to know Kotlin as an Android developer. When building Android apps, I'm used to using Databinding, retrolambda, etc. Now I am a bit lost on how to solve the following case in Kotlin.

How i usually do it in java

I have Adapter

(extends RecyclerView.Adapter

) for a RecyclerView

displaying a list BluetoothDevice

s. Typically, all my projects have a common TypedClickListener interface that returns the T-object of the list that the user has clicked on. For example:

Common interface:

public interface TypedClickListener<T> {
    void onClick(T t);
}

      

        
        
        
      

    

PairedDeviceAdapter constructor

public PairedDeviceAdapter(Context context, BluetoothDevice[] devices, TypedClickHandler<BluetoothDevice> handler){
    mContext = context;
    mDevices = devices
    mClickHandler = handler;
}

      

        
        
        
      

    

Adapter onBindViewHolder: (holder contains data binding layout)

public void onBindViewHolder(DatabindViewHolder holder, Int position) {
    holder.getBinding().setVariable(BR.device, mDevices[position]);
    holder.getBinding().setVariable(BR.handler, mClickHandler);
}

      

        
        
        
      

    

The layout itself:

<layout xmlns:android="http://schemas.android.com/apk/res/android">
    <data>
        <import type="android.bluetooth.BluetoothDevice"/>
        <import type="com.example.TypedClickHandler"/>
        <variable
            name="device"
            type="BluetoothDevice"/>
        <variable
            name="handler"
            type="TypedClickHandler"/>
    </data>
    <LinearLayout
        ... // width, height, etc
        android:onClick="@{v->handler.onClick(device)}">
        ... // Row layout etc
    </LinearLayout>
</layout>

      

        
        
        
      

    

Now, all together:

Passing TypedClickListener to adapter in Activity:

mAdapter = PairedDeviceAdapter(this, devices, (bluetoothDevice) -> {
    // The code that is ran when user clicks a device
}

      

        
        
        
      

    

How do I try to do it in Kotlin

As I said, I am trying to do this with Kotlin. It seems I can skip the step TypedClickListener

, as I can use a simple built-in function (BluetoothDevice) -> Unit

.

PairedDeviceAdapter looks like this:

class PairedDeviceAdapter(val context: Context, val clickHandler : (BluetoothDevice) -> Unit ) : RecyclerView.Adapter<DatabindViewHolder>() {

      

        
        
        
      

    

OnBindViewHolder looks the same as its Java version. However, I can't figure out how to bind my layout to the clicker as I don't have a click handler type.

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">
    <data>
        <import type="android.bluetooth.BluetoothDevice"/>
        <import type="???"/>
        <variable
            name="device"
            type="BluetoothDevice"/>
        <variable
            name="handler"
            type="???"/>
    </data>
    <LinearLayout
        ...
        android:onClick="@{v->handler.???(device)}">
        ... // close everything

      

        
        
        
      

    

Question

How can I create the same structure in Kotlin, or is there another (smarter?) Solution to bind a string-jumper to a lambda function defined in Activity

(or Fragment

).