Clicklistener Not Working In Recyclerview

Im following this link answer--> https://stackoverflow.com/a/32323801/12553303 ...on click of item im getting an error of invalid product id...but how do i get id from adapter

Solution 1:

To get response/data back from adapter to activity, you'll need to implement callback pattern like below example:

RecyclerView Adapter sudo code:

classRecyclerViewAdapter(
    other variables,
    privateval dataCallback: (Desired data type you want to return to activity) -> Unit// This is how you can construct lambda callback in Kotlin
): RecyclerView.Adaper..(){
    
    overridefunonBindViewHolder(...) {
        // Let's say here you have click listener or some other event on which you want data to send back to activity then simply call like below:
        dataCallback(outputData) // This can be `dataList?.get(position)?.product?.id`
    }
}

Activity callback sudo code:

classSampleActivity: AppCompatActivity() {
    lateinitvar adapter: RecyclerViewAdapter

    overridefunonCreate(...){
        adapter = RecyclerViewAdapter(other values) { desiredData ->
            // Here you can receive data back as callback
        }

        // Example from O.P.// val adapter = CartAdapter(this@AddToCart, dataList) { output ->  }
    }
}

Basically you create a callback receiver type on your adapter constructor as following:

nameOfCallbackVariable: (TypeOfDataYouWantToProvideBack) -> ReturnType

I.e. productSelectedCallback: (Int) -> Unit where you send your selected id (Int) back to consumer.

When you need to provide that data back, you can invoke it like this: nameOfCallbackVariable(valueOfIntType).