dp 정의

dimen.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <dimen name="offset">10dp</dimen>
    <dimen name="margin">50dp</dimen>
    <dimen name="total_margin">60dp</dimen>
</resources>

offset : 옆 아이템을 보여주는 길이margin : 아이템 간의 거리total_margin : offset + margin

레이아웃 작성

ViewPager2 를 배치하는 메인 레이아웃의 작성.

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.viewpager2.widget.ViewPager2
        android:id="@+id/view_pager"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

그런 다음 항목 레이아웃 만들기. 옆을 total_margin 분만 마진을 걸린다.

view_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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginStart="@dimen/total_margin"
    android:layout_marginEnd="@dimen/total_margin">

    <View
        android:layout_width="0dp"
        android:layout_height="200dp"
        android:background="@color/teal_200"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:text="1" />

</androidx.constraintlayout.widget.ConstraintLayout>

어댑터 작성

ViewPager 용 어댑터 작성

ItemAdapter.kt

class ItemAdapter(private val items: List<String>) :
    RecyclerView.Adapter<ItemAdapter.ViewHolder>() {

    class ViewHolder(val binding: ViewItemBinding) : RecyclerView.ViewHolder(binding.root)

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =
        ViewHolder(ViewItemBinding.inflate(LayoutInflater.from(parent.context), parent, false))

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        holder.binding.text.text = items[position]
    }

    override fun getItemCount() = items.size
}

처리 작성

마지막으로, 처리의 작성. sizeRate 를 변경하면 측면에 표시되는 항목의 크기가 변경됩니다.

MainActivity.kt

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val binding = ActivityMainBinding.inflate(layoutInflater)

        binding.viewPager.adapter = ItemAdapter(listOf("1", "2", "3"))
        binding.viewPager.offscreenPageLimit = 2
        binding.viewPager.setPageTransformer { page, position ->
            val sizeRate = 0.5F

            val margin = resources.getDimensionPixelOffset(R.dimen.margin)
            val offset = resources.getDimensionPixelOffset(R.dimen.offset)
            val itemWidth = binding.viewPager.width - (margin + offset) * 2
            page.translationX =
                -position * (2 * offset + margin + (1 - sizeRate) * itemWidth / 2)
            val scale = 1 - (kotlin.math.abs(position) * (1 - sizeRate))
            page.scaleX = scale
            page.scaleY = scale
        }
        setContentView(binding.root)
    }
}

참조 : htps : //사토신. 기주 b. 이오 / 2019/08 / ぃ えw ぱげ r2 - ぃ 케 - 아카로 우세 l /