Androidシステムクラスタ(recyclerview)kotlin(2)

🍏 「勾配の追加」(ViewBinding)の使用

android {
  ...
  viewBinding{
  	enabled true
}

🍎 なぜViewBindingを使うのですか?

🍎 ViewBindingシンボル!!

🍎 インプリメンテーション

🍏 recyclerviewをactivity mainに追加

<?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="0dp"
        android:layout_height="0dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        />


</androidx.constraintlayout.widget.ConstraintLayout>

🍏 itemviewビューレイアウトの作成

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <TextView
        android:id="@+id/tv_main"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Main TextView"
        android:textSize="24sp"
        android:padding="5dp"/>

    <TextView
        android:id="@+id/tv_sub"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Sub TextView"
        android:textSize="18sp"
        android:padding="5dp"/>
</LinearLayout>

🍏 recylcerview Adapterの実装

class RecyclerViewAdapter(private val dataSet: ArrayList<List<String>>) : RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder>(){
    override fun onCreateViewHolder(
        parent: ViewGroup,
        viewType: Int
    ): ViewHolder {
//        val view = LayoutInflater.from(parent.context).inflate(R.layout.list_item,parent,false)
//        return  ViewHolder(view)
        val binding = ListItemBinding.inflate(LayoutInflater.from(parent.context),parent,false)
        return  ViewHolder(binding)
    }

    override fun onBindViewHolder(holder: RecyclerViewAdapter.ViewHolder, position: Int) {
        holder.bind(dataSet[position])
    }

    override fun getItemCount(): Int = dataSet.size

    class ViewHolder(private val binding:ListItemBinding): RecyclerView.ViewHolder(binding.root){
        fun bind(data:List<String>){
            binding.tvMain.text = data[0]
            binding.tvSub.text =data[1]
        }
    }
//    class ViewHolder(view: View): RecyclerView.ViewHolder(view){
//        private val tvMain :TextView = view.tv_main
//        private val tvSub :TextView = view.tv_sub
//
//        fun bind(data:List<String>){
//            tvMain.text = data[0]
//            tvSub.text = data[1]
//        }
//    }
}

🍏 MainActivityの実装

class MainActivity : AppCompatActivity() {

    private val binding by lazy { ActivityMainBinding.inflate(layoutInflater) }
    private val dataSet: ArrayList<List<String>> = arrayListOf()
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(binding.root)





     binding. recyclerView.layoutManager = LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)
     binding.recyclerView.adapter = RecyclerViewAdapter(dataSet)


        addData()

    }

    private fun addData(){
        for (i in 0..99){
            dataSet.add(listOf("$i the main", "$i the sub"))
        }
    }

}

🍎 ビデオの実装

🍎 レイアウトマネージャGridLayoutに変更

// recylcerview 레이아웃매니저 지정
       // recyclerView.layoutManager = LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)
       binding.recyclerView.layoutManager =GridLayoutManager(this ,2)
        // recylcerview 어댑터 지정
        binding.recyclerView.adapter = RecyclerViewAdapter(dataSet)

🍎 整理する