[Kotlin] RecyclerView

build.gradle (Module: app)

dependencies {
    // RecyclerView 생성 (혀가 길지 않은 개발자)
    implementation 'androidx.recyclerview:recyclerview:1.1.0'
}

 

 

 

 

 

 

activity_main.xml

<?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"
    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/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />

</androidx.constraintlayout.widget.ConstraintLayout>

activity_main.xml

 

 

 

 

 

recyclerview_item.xml

<?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">

    <TextView
        android:id="@+id/txtView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="26dp"
        android:text="혀가 길지 않은 개발자"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        />

</androidx.constraintlayout.widget.ConstraintLayout>

recyclerview_item.xml

 

 

 

 

 

 

RecyclerViewAdapter.kt

package com.jwsoft.kotlinproject

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

class RecyclerViewAdapter(private val arrData: ArrayList<String>)
    : RecyclerView.Adapter<RecyclerViewAdapter.MyViewHolder>() {
    
    var data: ArrayList<String> = arrData

    // inner 클래스는 outer 클래스의 변수를 사용 할 수 있다. (data: ArrayList<String>)
    inner class MyViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        var txtView: TextView = itemView.findViewById(R.id.txtView)
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
        val context = parent.context
        val inflater = context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
        val view = inflater.inflate(R.layout.recyclerview_item, parent, false)

        return MyViewHolder(view)
    }

    override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
        holder.txtView.text = data[position] + "번째 혀가 길지 않은 개발자"
    }

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

 

 

 

 

 

 

 

MainActivity.kt

package com.jwsoft.kotlinproject

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        var arrData = ArrayList<String>()
        for (i in 1..100) {
            arrData.add(i.toString())
        }

        val recyclerView: RecyclerView = findViewById(R.id.recyclerView)
        recyclerView.layoutManager = LinearLayoutManager(
            applicationContext,
            RecyclerView.VERTICAL,
            false)
        val adapter = RecyclerViewAdapter(arrData)
        recyclerView.adapter = adapter
        recyclerView.addItemDecoration(DividerItemDecoration(this, LinearLayout.VERTICAL))
    }
}

실행 결과