[Android] RecyclerView 예제

// User.kt (데이터 클래스)
data class User(
    val id: Int,
    val name: String,
    val location: String
)​

<!-- res/layout/user_list_item.xml -->
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="10dp">

    <ImageView
        android:id="@+id/user_image"
        android:layout_width="50dp"
        android:src="@mipmap/ic_launcher"
        android:layout_height="50dp" />

    <TextView
        android:id="@+id/user_name_text"
        android:layout_width="wrap_content"
        android:textSize="20sp"
        android:gravity="center"
        android:layout_marginStart="10dp"
        android:layout_height="match_parent" />
</LinearLayout>

// UserAdapter.kt (Adapter 클래스)
class UserAdapter(
    private val mContext: Context,
    private val mList: MutableList<User>
) : RecyclerView.Adapter<UserAdapter.ViewHolder>() {

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

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        val user = mList[position]
        holder.bind(user)
    }

    override fun getItemCount(): Int = mList.size

    inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        fun bind(user: User) {
            itemView.findViewById<TextView>(R.id.user_name_text).text = user.name
            if (user.location != "기존의 장소명") {
                // 장소가 다른 경우 파란색으로 표시
                itemView.findViewById<TextView>(R.id.user_name_text).setTextColor(Color.BLUE)
            }
        }
    }
}

 

// MainActivity.kt (안드로이드 메인 코드)
class MainActivity : AppCompatActivity() {

    private lateinit var recyclerView: RecyclerView
    private lateinit var userAdapter: UserAdapter
    private val userList = mutableListOf<User>()

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

        // RecyclerView 초기화
        recyclerView = findViewById(R.id.recyclerView)
        userAdapter = UserAdapter(this, userList)
        recyclerView.adapter = userAdapter
        recyclerView.layoutManager = LinearLayoutManager(this)

        // 데이터 추가 (예시)
        userList.add(User(1, "Alice", "New York"))
        userList.add(User(2, "Bob", "Los Angeles"))
        userList.add(User(3, "Charlie", "Chicago"))

        // 데이터 변경 알림
        userAdapter.notifyDataSetChanged()
    }
}