[Android/Kotlin] viewpager2를 통한 가로 슬라이드 구현

ViewPager2
스와이프할 수 있는 형식으로 view 또는 fragment를 표시할 수 있다

 

 

1. build.gradle에 라이브러리 추가

implementation 'me.relex:circleindicator:2.1.6'

 

 

2. 스와이프 할 때마다 보여질 fragment

package com.mobile.mydrawer

import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup

class FirstFragment : Fragment() {
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_first, container, false)
    }
}

package com.mobile.mydrawer

import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup

class SecondFragment : Fragment() {
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_second, container, false)
    }
}

package com.mobile.mydrawer

import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup

class ThirdFragment : Fragment() {
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_third, container, false)
    }
}

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#BAF3FA"
    tools:context=".FirstFragment" />

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#EEF3BC"
    tools:context=".FirstFragment" />

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#CFBFEC"
    tools:context=".FirstFragment" />

 

 

3. MainActivity

FrameLayout 위에 viewpager2, indicator 추가

★FragmentStatementAdapter 상속

★createFragment의 파라미터가 position

 

package com.mobile.mydrawer

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Toast
import androidx.fragment.app.Fragment
import androidx.fragment.app.FragmentActivity
import androidx.viewpager.widget.PagerAdapter
import androidx.viewpager2.adapter.FragmentStateAdapter
import androidx.viewpager2.widget.ViewPager2
import kotlinx.android.synthetic.main.activity_main.*

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

        pager.adapter = PagerAdapter(this)
        pager.orientation = ViewPager2.ORIENTATION_HORIZONTAL
        pager.offscreenPageLimit = 3 //초기화해서 메모리를 미리 만들어놓음
        pager.registerOnPageChangeCallback(object : ViewPager2.OnPageChangeCallback(){
            override fun onPageSelected(position: Int) {
                super.onPageSelected(position)

                showToast("페이지 선택 : ${position}")
                indicator.animatePageSelected(position)
            }
        })

        //frameLayout은 위에 중첩해서 올릴 수 있다
        indicator.setViewPager(pager)
        indicator.createIndicators(3, 0)

        button.setOnClickListener{
            pager.currentItem = 0
        }

        button2.setOnClickListener{
            pager.currentItem = 1
        }
        button3.setOnClickListener{
            pager.currentItem = 2
        }
    }

    fun showToast(message:String){
        Toast.makeText(applicationContext, message, Toast.LENGTH_LONG).show()
    }

    inner class PagerAdapter : FragmentStateAdapter{
        constructor(activity: FragmentActivity):super(activity) //생성자

        override fun getItemCount() = 3

        override fun createFragment(position: Int): Fragment {
            when(position) {
                0 -> {
                    return FirstFragment()
                }
                1 -> {
                    return SecondFragment()
                }
                2 -> {
                    return ThirdFragment()
                }
                else -> {
                    return FirstFragment()
                }
            }
        }

    }
}

<?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">

    <LinearLayout
        android:id="@+id/linearLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintStart_toStartOf="parent">

        <Button
            android:id="@+id/button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="첫번째" />

        <Button
            android:id="@+id/button2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="두번째" />

        <Button
            android:id="@+id/button3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="세번째" />

    </LinearLayout>

    <FrameLayout
        android:layout_width="411dp"
        android:layout_height="646dp"
        android:layout_marginEnd="6dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/linearLayout">

        <androidx.viewpager2.widget.ViewPager2
            android:id="@+id/pager"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="1">
        </androidx.viewpager2.widget.ViewPager2>

        <me.relex.circleindicator.CircleIndicator3
            android:id="@+id/indicator"
            android:layout_width="match_parent"
            android:layout_height="48dp"
            android:layout_gravity="bottom"/>
    </FrameLayout>

</androidx.constraintlayout.widget.ConstraintLayout>