ViewPager2와 Fragment 예제

Swipe 모션으로 Fragment 페이지 넘기기 기능을 하는 ViewPager2를 구현해보자.

 

1. build.gradle ( Module: ~~) 에서 ViewPager 라이브러리 설치

implementation 'androidx.viewpager2:viewpager2:1.0.0'

※ Tips. gradle에 androidx에서 제공하는 라이브러리 설치할 때 최신버전으로 받고 싶다면 타이핑말고 검색해서 설치할 수 있다.

1. File > Project Structure...  ( 또는 Ctrl + Alt + Shift + S )

2. Dependencies > + > Library Dependency

3. 설치하고자 하는 라이브러리 (androidx.viewpager2) 검색해서 오른쪽에 버전 선택 (최상단이 최신버전)

4. OK > Apply > OK 하면 자동으로 설치되고 dependencies 확인해보면 알아서 입력되어있음.

 

 

2. 레이아웃 구현

- 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/viewPager2_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

 

- fragment1.xml (생성)

<?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"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Fragment1"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

 

- fragment2.xml (생성)

<?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"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Fragment2"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

 

 

 

3. 컨트롤러 구현

- Fragment1.java (생성)

package com.example.example_viewpager2;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;

public class Fragment1 extends Fragment {
    public static Fragment1 newInstance(int number) {
        Fragment1 fragment1 = new Fragment1();
        Bundle bundle = new Bundle();
        bundle.putInt("number", number);
        fragment1.setArguments(bundle);
        return fragment1;
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if (getArguments() != null) {
            int num = getArguments().getInt("number");
        }
    }

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return LayoutInflater.from(inflater.getContext()).inflate(R.layout.fragment1, container, false);
    }
}

 

- Fragment2.java (생성)

package com.example.example_viewpager2;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;

public class Fragment2 extends Fragment {
    public static Fragment2 newInstance(int number) {
        Fragment2 fragment2 = new Fragment2();
        Bundle bundle = new Bundle();
        bundle.putInt("number", number);
        fragment2.setArguments(bundle);
        return fragment2;
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if (getArguments() != null) {
            int num = getArguments().getInt("number");
        }
    }

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return LayoutInflater.from(inflater.getContext()).inflate(R.layout.fragment2, container, false);
    }
}

 

- ViewPager2Adapter.java (생성)

package com.example.example_viewpager2;

import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentActivity;
import androidx.viewpager2.adapter.FragmentStateAdapter;

import java.util.ArrayList;

public class ViewPager2Adapter extends FragmentStateAdapter {
    private ArrayList<Fragment> mFragments;

    public ViewPager2Adapter(@NonNull FragmentActivity fragmentActivity, ArrayList list) {
        super(fragmentActivity);
        this.mFragments = list;
    }

    @NonNull
    @Override
    public Fragment createFragment(int position) {
        return mFragments.get(position);
    }

    @Override
    public int getItemCount() {
        return mFragments.size();
    }
}

 

- MainActivity.java

package com.example.example_viewpager2;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.viewpager2.widget.ViewPager2;

import android.os.Bundle;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {
    private ViewPager2 viewPager2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ArrayList<Fragment> fragments = new ArrayList<>();
        fragments.add(Fragment1.newInstance(0));
        fragments.add(Fragment2.newInstance(1));

        viewPager2 = (ViewPager2) findViewById(R.id.viewPager2_container);

        ViewPager2Adapter viewPager2Adapter = new ViewPager2Adapter(this, fragments);
        viewPager2.setAdapter(viewPager2Adapter);
    }
}

 

 

>>> 참고

 

 

 

 

끝