리사이클러뷰 어댑터 보일러플레이트 코드

RecyclerView Adapter Boilerplate Code

#1 기본적인 어댑터 

import android.content.Context
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.recyclerview.widget.RecyclerView
import androidx.recyclerview.widget.RecyclerView.ViewHolder

class MyAdapter: RecyclerView.Adapter<MyAdapter.MyViewHolder>() {
    private var context: Context? = null

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.item_list, parent, false)
        context = parent.context

        return MyViewHolder(view)
    }

    override fun getItemCount(): Int {
        TODO("Not yet implemented")
    }

    override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
        TODO("Not yet implemented")
    }

    class MyViewHolder(itemView: View) : ViewHolder(itemView) {

    }
}

 

#2 데이터를 추가한 어댑터

class UserData(var name: String, var age: Int, var gender: String) {
    fun getAgeString(): String = age.toString()
}

import android.view.ViewGroup
import android.view.LayoutInflater
import androidx.recyclerview.widget.RecyclerView
import kotlinx.android.synthetic.main.item_list.view.*

class MyAdapter: RecyclerView.Adapter<MyAdapter.MyViewHolder>() {
    private val items = mutableListOf<UserData>()

    fun setItems(_items: List<UserData>) {
        _items.let {
            items.clear()
            items.addAll(it)
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) = MyViewHolder(parent)

    override fun getItemCount(): Int = items.size

    override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
        holder.onBindViewHolder(items[position])
    }

    inner class MyViewHolder(parent: ViewGroup) : RecyclerView.ViewHolder(
        LayoutInflater.from(parent.context).inflate(R.layout.item_list, parent, false)
    ) {
        fun onBindViewHolder(item: UserData) {
            with(itemView) {
                tvName.text = item.name
                tvAge.text = item.age.toString()
                tvGender.text = item.gender
            }
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    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">

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="60dp"
        android:orientation="horizontal"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent">

        <TextView
            android:id="@+id/tvName"
            android:layout_width="100dp"
            android:layout_height="match_parent"/>

        <TextView
            android:id="@+id/tvAge"
            android:layout_width="100dp"
            android:layout_height="match_parent"/>

        <TextView
            android:id="@+id/tvGender"
            android:layout_width="100dp"
            android:layout_height="match_parent"/>

    </LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

 

#3 데이터 바인딩을 이용한 어댑터

import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.recyclerview.widget.RecyclerView
import com.lee.storagetest.databinding.ItemListBinding

class MyAdapter: RecyclerView.Adapter<MyAdapter.MyViewHolder>() {
    private val items = mutableListOf<UserData>()

    fun setItems(_items: List<UserData>) {
        _items.let {
            items.clear()
            items.addAll(it)
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
        var binding = ItemListBinding.inflate(LayoutInflater.from(parent.context), parent, false)
        return MyViewHolder(binding, binding.root)
    }

    override fun getItemCount(): Int = items.size

    override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
        holder.bind(items[position])
    }

    inner class MyViewHolder(private val binding: ItemListBinding, itemView: View) : RecyclerView.ViewHolder(
        itemView
    ) {
        fun bind(item: UserData) {
            binding.data = item
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <data>
        <variable
            name="data"
            type="com.lee.storagetest.list.UserData" />
    </data>

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

        <LinearLayout
            android:layout_width="0dp"
            android:layout_height="60dp"
            android:orientation="horizontal"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintEnd_toEndOf="parent">

            <TextView
                android:id="@+id/tvName"
                android:layout_width="100dp"
                android:layout_height="match_parent"
                android:text="@{data.name}"/>

            <TextView
                android:id="@+id/tvAge"
                android:layout_width="100dp"
                android:layout_height="match_parent"
                android:text="@{data.getAgeString()}"/>

            <TextView
                android:id="@+id/tvGender"
                android:layout_width="100dp"
                android:layout_height="match_parent"
                android:text="@{data.gender}"/>

        </LinearLayout>
    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>