안드로이드 앱 개발 연습 - 3 | Spinner & RecyclerView

Spinner

MainActivity.kt

class MainActivity : AppCompatActivity() {
    private val binding by lazy { ActivityMainBinding.inflate(layoutInflater) }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(binding.root)

        val spinnerData = listOf<String>("First", "Second", "Third")
        val spinnerAdapter = ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, spinnerData)
        binding.spinner.adapter = spinnerAdapter
        binding.spinner.onItemSelectedListener = object: AdapterView.OnItemSelectedListener {
            override fun onItemSelected(parent: AdapterView<*>?, view: View?, position: Int, id: Long) {
                binding.spinnerText.text = spinnerData[position]
            }
            override fun onNothingSelected(parent: AdapterView<*>?) {}
        }
    }
}

---

RecyclerView

Memo.kt

data class Memo(var no: Int, var title: String, var timestamp: Long)

MainActivity.kt

class MainActivity : AppCompatActivity() {
    private val binding by lazy { ActivityMainBinding.inflate(layoutInflater) }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(binding.root)

        val recyclerData: MutableList<Memo> = loadRecyclerData()
        var recyclerAdapter = CustomAdapter()
        recyclerAdapter.listData = recyclerData
        binding.recyclerView.adapter = recyclerAdapter
        binding.recyclerView.layoutManager = LinearLayoutManager(this)
    }

    fun loadRecyclerData(): MutableList<Memo> {
        val data: MutableList<Memo> = mutableListOf()
        for (no in 1..100) {
            val title = "This is Kotlin Android $no"
            val date = System.currentTimeMillis()
            var memo = Memo(no, title, date)
            data.add(memo)
        }
        return data
    }
}

CustomAdapter.kt

class CustomAdapter: RecyclerView.Adapter<Holder>() {
    var listData = mutableListOf<Memo>()
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): Holder {
        val binding = ItemRecyclerBinding.inflate(LayoutInflater.from(parent.context), parent, false)
        return Holder(binding)
    }

    override fun onBindViewHolder(holder: Holder, position: Int) {
        val memo = listData.get(position)
        holder.setMemo(memo)
    }

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

class Holder(val binding: ItemRecyclerBinding): RecyclerView.ViewHolder(binding.root) {
    init {
        binding.root.setOnClickListener {
            Toast.makeText(binding.root.context, "${binding.textTitle.text}", Toast.LENGTH_SHORT).show()
        }
    }

    fun setMemo(memo: Memo) {
        binding.textNo.text = "${memo.no}"
        binding.textTitle.text = memo.title
        binding.textDate.text = SimpleDateFormat("yyyy/MM/dd").format(memo.timestamp)
    }
}

Holder에 사용하는 ItemRecyclerBinding은 어댑터에서 사용하는 레이아웃의 이름이 item_recycler이기 때문이다. 해당 레이아웃은 res >> layout에서 생성하여 recyclerView의 형태를 정의하는데 사용된다.