📌 Fragment+BottomNavigationView

• 화면 전환
• 하단 메뉴 구성
• 하단 메뉴 선택으로 화면(Fragment) 전환 기능 구현
• ex) 카카오톡 메인 화면 등...

📍 BottomNavigationView 구현 + Fragment 작성 & 연결

1. menu 작성 (레이아웃)

menu [폴더] -> New -> Menu Resource File

bottom_navigation.xml

• 하단 메뉴로 사용할 Item 종류 작성
• 메뉴 이미지 등록은 drawble [폴더]에 이미지 파일 넣기

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/menu1"
        android:enabled="true"
        android:icon="@drawable/ic_info"
        android:title="fragment1"
        />

    <item
        android:id="@+id/menu2"
        android:enabled="true"
        android:icon="@drawable/ic_home"
        android:title="fragment2"
        />

    <item
        android:id="@+id/menu3"
        android:enabled="true"
        android:icon="@drawable/ic_settings"
        android:title="fragment3"
        />

</menu>

2. 메인 화면에 BottomNavigaionView 삽입하기 (레이아웃)

activity_main.xml

• LinearLayout으로 중앙에 전환 된 Fragment가 나타날 공간을 작성
• 하단에 이동 메뉴탭인 BottomNavigationView 작성

<?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/layout00"
        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_toTopOf="@id/bottom_navigation"
        android:orientation="horizontal" />

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottom_navigation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toBottomOf="@id/layout00"
        app:menu="@menu/bottom_navigation"
        />


    </androidx.constraintlayout.widget.ConstraintLayout>

3. 전환 할 Fragment 화면 구현 (레이아웃)

fragment1.xml

• 전환 시 보여질 Fragment 화면 구현

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:background="@color/blue">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/txt1"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        android:text="Fragment1"
        android:textColor="@color/black"
        />

</androidx.constraintlayout.widget.ConstraintLayout>

fragment2.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:background="@color/mint">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        android:id="@+id/txt2"
        android:text="Fragment2"
        android:textColor="@color/black"
        />

</androidx.constraintlayout.widget.ConstraintLayout>

fragment3.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:background="@color/yellow2">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        android:id="@+id/txt3"
        android:text="Fragment3"
        android:textColor="@color/black"
        />

</androidx.constraintlayout.widget.ConstraintLayout>

4. Fragment 화면 레이아웃의 자바파일 작성 (Java)

Fragment1.java

• 작성한 Fragment(레이아웃)와 자바파일 연결

package com.example.fragment_bottomnavigationview;

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

Fragment2.java

package com.example.fragment_bottomnavigationview;

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

Fragment3.java

package com.example.fragment_bottomnavigationview;

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 Fragment3 extends Fragment {
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment3, container, false);
    }
}

5. Fragment와 Menu 연결

MainActivity.java

• Fragment를 BottomNavigationView의 각 메뉴들과 연결
• 각 메뉴 선택 시 Fragment 전환 기능 구현

package com.example.fragment_bottomnavigationview;

import android.os.Bundle;
import android.util.Log;
import android.view.MenuItem;
import android.widget.LinearLayout;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import com.google.android.material.bottomnavigation.BottomNavigationView;
import com.google.android.material.navigation.NavigationBarView;

public class MainActivity extends AppCompatActivity {

    private FragmentManager fragmentManager = getSupportFragmentManager();
    private Fragment1 fragment1 = new Fragment1();
    private Fragment2 fragment2 = new Fragment2();
    private Fragment3 fragment3 = new Fragment3();

    private BottomNavigationView bottomNavigationView;
    private LinearLayout containerView;

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

        bottomNavigationView = findViewById(R.id.bottom_navigation);
        containerView = findViewById(R.id.layout00);

        FragmentTransaction transaction = fragmentManager.beginTransaction();
        transaction.replace(R.id.layout00, fragment1, null);
        transaction.commit();

        bottomNavigationView.setOnItemSelectedListener(new NavigationBarView.OnItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                switch (item.getItemId()) {
                    case R.id.menu1:
                        Log.wtf("MainActivity", "menu1 Click");       //Log 보기
                        fragmentManager.beginTransaction().replace(R.id.layout00, fragment1).commit();
                        transaction.addToBackStack(null);   //.addToBackStack(null) 추가 시 -> 스택에 쌓이므로 뒤로가기 시 스택에 있는 프래그먼트들이 순서대로 onDestory 된다.
                        break;                              // 뒤로 가기 기능.

                    case R.id.menu2:
                        Log.wtf("MainActivity", "menu2 Click");
                        fragmentManager.beginTransaction().replace(R.id.layout00, fragment2).commit();
                        transaction.addToBackStack(null);
                        break;

                    case R.id.menu3:
                        Log.wtf("MainActivity", "menu3 Click");
                        fragmentManager.beginTransaction().replace(R.id.layout00, fragment3).commit();
                        transaction.addToBackStack(null);
                        break;
                }
                return true;
            }
        });
    }
}

📌 완성

작성한 전체 소스코드 github : Android_Study/fragment_bottomnavigationview/