如何在嵌套的recyclerview上实现onClick监听器

Question

I am trying to implement a click listener on a nested recyclerview so that when an item on the child recycler view is clicked, an action is performed. I can do it for the parent recyclerview, but can't seem to do it for child recyclerview items. I really appreciate you time and assistance on this.

Below is my MainActivity.kt

package com.example.nestedrecyclerview

import android.view.LayoutInflater
import android.view.View
import android.view.View.OnClickListener
import android.view.ViewGroup
import android.widget.ImageView
import android.widget.TextView
import androidx.recyclerview.widget.GridLayoutManager
import androidx.recyclerview.widget.RecyclerView

class ParentAdapter(private val parentList: List<ParentItem>,
       private val listener : OnItemClickListener ) :
    RecyclerView.Adapter<ParentAdapter.ParentViewHolder>() {

    inner class ParentViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView), View.OnClickListener {
        val logoIv: ImageView = itemView.findViewById(R.id.parentLogoIv)
        val titleTv: TextView = itemView.findViewById(R.id.parentTitleTv)
        val childRecyclerView: RecyclerView = itemView.findViewById(R.id.ch)

        init {
            itemView.setOnClickListener(this)
        }

        override fun onClick(p0: View?) {
            val position : Int = adapterPosition
            if (position != RecyclerView.NO_POSITION) {
                listener.onItemClick(position)
            }
        }
    }

    interface OnItemClickListener{
        fun onItemClick(position: Int)
    }



    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ParentViewHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.parent_item, parent, false)
        return ParentViewHolder(view)
    }

    override fun onBindViewHolder(holder: ParentViewHolder, position: Int) {
        val parentItem = parentList[position]
        holder.logoIv.setImageResource(parentItem.logo)
        holder.titleTv.text = parentItem.title

        holder.childRecyclerView.setHasFixedSize(true)
        holder.childRecyclerView.layoutManager = GridLayoutManager(holder.itemView.context, 3)
        val adapter = ChildAdapter(parentItem.mList)
        holder.childRecyclerView.adapter = adapter
    }

    override fun getItemCount(): Int {
        return parentList.size
    }
}

======================================================

Below is ParentAdapter.kt

class ParentAdapter(private val parentList: List<ParentItem>,
       private val listener : OnItemClickListener ) :
    RecyclerView.Adapter<ParentAdapter.ParentViewHolder>() {

    inner class ParentViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView), View.OnClickListener {
        val logoIv: ImageView = itemView.findViewById(R.id.parentLogoIv)
        val titleTv: TextView = itemView.findViewById(R.id.parentTitleTv)
        val childRecyclerView: RecyclerView = itemView.findViewById(R.id.ch)

        init {
            itemView.setOnClickListener(this)
        }

        override fun onClick(p0: View?) {
            val position : Int = adapterPosition
            if (position != RecyclerView.NO_POSITION) {
                listener.onItemClick(position)
            }
        }
    }

    interface OnItemClickListener{
        fun onItemClick(position: Int)
    }



    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ParentViewHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.parent_item, parent, false)
        return ParentViewHolder(view)
    }

    override fun onBindViewHolder(holder: ParentViewHolder, position: Int) {
        val parentItem = parentList[position]
        holder.logoIv.setImageResource(parentItem.logo)
        holder.titleTv.text = parentItem.title

        holder.childRecyclerView.setHasFixedSize(true)
        holder.childRecyclerView.layoutManager = GridLayoutManager(holder.itemView.context, 3)
        val adapter = ChildAdapter(parentItem.mList)
        holder.childRecyclerView.adapter = adapter
    }

    override fun getItemCount(): Int {
        return parentList.size
    }
}

====================================================

Below is ChildAdapter.kt

import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ImageView
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView

class ChildAdapter(private val childList: List<ChildItem>,
     private val listener : OnItemClickListener) :
    RecyclerView.Adapter<ChildAdapter.ChildViewHolder>() {

    inner class ChildViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView),
    View.OnClickListener{
        val logo: ImageView = itemView.findViewById(R.id.childLogoIv)
        val title: TextView = itemView.findViewById(R.id.childTitleTv)

        init {
            itemView.setOnClickListener(this)
        }

        override fun onClick(p0: View?) {
            val position = adapterPosition
            if (position != RecyclerView.NO_POSITION)
            listener.onChildItemClick(position)
        }
    }

    interface OnItemClickListener {
        fun onChildItemClick(position: Int)

    }



    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ChildViewHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.child_item, parent, false)
        return ChildViewHolder(view)
    }

    override fun onBindViewHolder(holder: ChildViewHolder, position: Int) {
        holder.logo.setImageResource(childList[position].logo)
        holder.title.text = childList[position].title
    }

    override fun getItemCount(): Int {
        return childList.size
    }

}

======================================

Below is parent_item.xml

<?xml version="1.0" encoding="utf-8"?>
<com.google.android.material.card.MaterialCardView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginHorizontal="8dp"
    app:cardCornerRadius="8dp"
    app:cardElevation="5dp"
    app:cardUseCompatPadding="true">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <androidx.constraintlayout.widget.ConstraintLayout
            android:id="@+id/constraintLayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="8dp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent">

            <androidx.cardview.widget.CardView
                android:id="@+id/cardView"
                android:layout_width="30dp"
                android:layout_height="30dp"
                app:cardCornerRadius="100dp"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent">

                <ImageView
                    android:id="@+id/parentLogoIv"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent" />
            </androidx.cardview.widget.CardView>

            <TextView
                android:id="@+id/parentTitleTv"
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:layout_marginStart="12dp"
                android:text="Language"
                android:textColor="@color/black"
                android:textSize="16sp"
                android:textStyle="bold"
                app:layout_constraintBottom_toBottomOf="@+id/cardView"
                app:layout_constraintStart_toEndOf="@id/cardView"
                app:layout_constraintTop_toTopOf="parent" />

        </androidx.constraintlayout.widget.ConstraintLayout>

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/childRecyclerView"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginBottom="8dp"
            android:padding="8dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@id/constraintLayout" />

    </androidx.constraintlayout.widget.ConstraintLayout>

</com.google.android.material.card.MaterialCardView>

=============================================================

Below is child_item.xml

<com.google.android.material.card.MaterialCardView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:cardElevation="5dp"
    app:cardUseCompatPadding="true">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <androidx.cardview.widget.CardView
            android:id="@+id/childCardView"
            android:layout_width="40dp"
            android:layout_height="40dp"
            android:layout_marginTop="8dp"
            app:cardCornerRadius="100dp"
            app:cardElevation="2dp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent">

            <ImageView
                android:id="@+id/childLogoIv"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:src="@drawable/java" />
        </androidx.cardview.widget.CardView>

        <TextView
            android:id="@+id/childTitleTv"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_marginVertical="5dp"
            android:text="Language"
            android:textColor="@color/black"
            android:textSize="14sp"
            android:textStyle="bold"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="@id/childCardView"
            app:layout_constraintStart_toStartOf="@id/childCardView"
            app:layout_constraintTop_toBottomOf="@+id/childCardView" />
    </androidx.constraintlayout.widget.ConstraintLayout>

</com.google.android.material.card.MaterialCardView>

==================================================

Below is activity_main.xml

<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/parentRecyclerView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

Answer 1

You can set the tag on the View in onBindViewHolder, set the click listener to get the tag attribute and proceed to the next step of logic.

The following is an example of my writing: here I set the click event listener for the entire View.

package com.example.nestedrecyclerview

import android.view.LayoutInflater
import android.view.View
import android.view.View.OnClickListener
import android.view.ViewGroup
import android.widget.ImageView
import android.widget.TextView
import androidx.recyclerview.widget.GridLayoutManager
import androidx.recyclerview.widget.RecyclerView
import com.kotlinx.stackoverflowtestapplication.R

class ParentAdapter(private val parentList: List<ParentItem>,
                    private val listener : OnItemClickListener ) :
    RecyclerView.Adapter<ParentAdapter.ParentViewHolder>() {

    inner class ParentViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val logoIv: ImageView = itemView.findViewById(R.id.parentLogoIv)
        val titleTv: TextView = itemView.findViewById(R.id.parentTitleTv)
        val childRecyclerView: RecyclerView = itemView.findViewById(R.id.ch)
    }

    private val onClickListener: OnClickListener = OnClickListener {
        if (it.tag is Int) {
            val position = it.tag
            TODO()
        }
    }


    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ParentViewHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.parent_item, parent, false)
        view.setOnClickListener(onClickListener)
        return ParentViewHolder(view)
    }

    override fun onBindViewHolder(holder: ParentViewHolder, position: Int) {
        holder.itemView.tag = position
        val parentItem = parentList[position]
        holder.logoIv.setImageResource(parentItem.logo)
        holder.titleTv.text = parentItem.title

        holder.childRecyclerView.setHasFixedSize(true)
        holder.childRecyclerView.layoutManager = GridLayoutManager(holder.itemView.context, 3)
        val adapter = ChildAdapter(parentItem.mList)
        holder.childRecyclerView.adapter = adapter
    }

    override fun getItemCount(): Int {
        return parentList.size
    }
}