Bottom Navigation View

dependencies {
    implementation 'com.google.android.material:material:1.1.0'
}

1. drawable 디렉토리에 Vector Asset 5개를 추가한다.
2. res/menu 폴더를 만들고 bottom_menu.xml 파일을 만든다.

<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/action_airplane"
        android:enabled="true"
        android:icon="@drawable/ic_baseline_flight_24"
        android:title="비행기"/>

    <item
        android:id="@+id/action_airport"
        android:enabled="true"
        android:icon="@drawable/ic_baseline_filter_drama_24"
        android:title="버스"/>

    <item
        android:id="@+id/action_bt"
        android:enabled="true"
        android:icon="@drawable/ic_baseline_emoji_events_24"
        android:title="블루투스"/>

    <item
        android:id="@+id/action_call"
        android:enabled="true"
        android:icon="@drawable/ic_baseline_drive_eta_24"
        android:title="전화"/>

    <item
        android:id="@+id/action_run"
        android:enabled="true"
        android:icon="@drawable/ic_baseline_comment_24"
        android:title="사람"/>
</menu>

1. frag1.xml 부터 frag5.xml 까지 5개를 만든다.

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="1번화면 입니다."
        android:textSize="40sp"/>

</LinearLayout>

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">

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottomNavi"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        android:background="#EEEEEE"
        app:menu="@menu/bottom_menu" />

    <FrameLayout
        android:id="@+id/main_frame"
        android:layout_width="match_parent"
        android:layout_height="659dp"
        app:layout_constraintBottom_toTopOf="@+id/bottomNavi"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

1. Frag1.java 부터 Frag5.java 까지 5개를 만든다.

public class Frag1 extends Fragment {

    private View view;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        view = inflater.inflate(R.layout.frag1, container, false);
        return view;
    }
}

MainActivity.java

public class MainActivity extends AppCompatActivity {

    private BottomNavigationView bottomNavigationView; // 바텀 네비게이션 뷰
    private FragmentManager fm;
    private FragmentTransaction ft;
    private Frag1 frag1;
    private Frag2 frag2;
    private Frag3 frag3;
    private Frag4 frag4;
    private Frag5 frag5;

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

        bottomNavigationView = findViewById(R.id.bottomNavi);
        bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
                switch (menuItem.getItemId()) {
                    case R.id.action_airplane:
                        setFrag(0);
                        break;
                    case R.id.action_airport:
                        setFrag(1);
                        break;
                    case R.id.action_bt:
                        setFrag(2);
                        break;
                    case R.id.action_call:
                        setFrag(3);
                        break;
                    case R.id.action_run:
                        setFrag(4);
                        break;
                }
                return true;
            }
        });
        frag1 = new Frag1();
        frag2 = new Frag2();
        frag3 = new Frag3();
        frag4 = new Frag4();
        frag5 = new Frag5();
        setFrag(0); // 첫 프래그먼트 화면을 무엇으로 지정해줄 것인지 선택.
    }

    // 프래그먼트 교체가 일어나는 실행문이다.
    private void setFrag(int n) {
        fm = getSupportFragmentManager();
        ft = fm.beginTransaction();
        switch (n) {
            case 0:
                ft.replace(R.id.main_frame, frag1);
                ft.commit();
                break;
            case 1:
                ft.replace(R.id.main_frame, frag2);
                ft.commit();
                break;
            case 2:
                ft.replace(R.id.main_frame, frag3);
                ft.commit();
                break;
            case 3:
                ft.replace(R.id.main_frame, frag4);
                ft.commit();
                break;
            case 4:
                ft.replace(R.id.main_frame, frag5);
                ft.commit();
                break;
        }
    }
}

안드로이드 앱 만들기 #25 SNS 앱 만들기 #1 (인스타 하단바)
https://www.youtube.com/watch?v=stwCk_f3sCw

홍드로이드 깃헙
https://github.com/hongdroid94/25_BottomNavigationMenu