Fragment with Bottom Navigation

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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="com.tecent.MainActivity">
 
    <FrameLayout
        android:id="@+id/fragment_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@id/bottom_navigation"/>
 
    <android.support.design.widget.BottomNavigationView
        android:id="@+id/bottom_navigation_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        app:menu="@menu/bottom_navigation"
        android:background="?android:attr/windowBackground"/>
 
</RelativeLayout>

bottom_navigation_menu.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/nav_home"
        android:icon="@drawable/ic_home_black_24dp"
        android:title="Home"/>
    <item
        android:id="@+id/nav_dashboard"
        android:icon="@drawable/ic_dashboard_black_24dp"
        android:title="Dashboard"/>
    <item
        android:id="@+id/nav_test_series"
        android:icon="@drawable/ic_open_book"
        android:title="Test series"/>
    <item
        android:id="@+id/nav_doubt"
        android:icon="@drawable/ic_question"
        android:title="Doubts"/>
</menu>

DashBoardFragment.java

package com.tecent.bottomnavigationviewexample;
 
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
 
 
public class DashBoardFragmentextends Fragment {
 
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_dashboard, container, false);
    }
}

DoubtsFragment.java

package com.tecent.bottomnavigationviewexample;
 
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
 
 
public class DoubtsFragmentFragment {
 
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_doubts, container, false);
    }
}

fragment_dashboard.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/holo_red_light">
 
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="dashboardFragment"
        android:textSize="30sp"
        android:layout_centerInParent="true"/>
 
</RelativeLayout>

fragment_doubts.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/holo_red_light">
 
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="DoubtsFragment"
        android:textSize="30sp"
        android:layout_centerInParent="true"/>
 
</RelativeLayout>

fragment_home.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/holo_red_light">
 
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Home Fragment"
        android:textSize="30sp"
        android:layout_centerInParent="true"/>
 
</RelativeLayout>

fragment_test_series.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/holo_red_light">
 
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Test SeriesFragment"
        android:textSize="30sp"
        android:layout_centerInParent="true"/>
 
</RelativeLayout>

HomeFragment.java

package com.tecent.bottomnavigationviewexample;
 
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
 
 
public class HomeFragment extends Fragment {
 
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_home, container, false);
    }
}

MainActivity.java

package com.tecent.bottomnavigationviewexample;
 
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v4.app.Fragment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;
 
public class MainActivity extends AppCompatActivity {
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        BottomNavigationView bottomNav = findViewById(R.id.bottom_navigation_view);
        bottomNav.setOnNavigationItemSelectedListener(navListener);
 
        //I added this if statement to keep the selected fragment when rotating the device
        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
                    new HomeFragment()).commit();
        }
    }
 
    private BottomNavigationView.OnNavigationItemSelectedListener navListener =
            new BottomNavigationView.OnNavigationItemSelectedListener() {
                @Override
                public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                    Fragment selectedFragment = null;
 
                    switch (item.getItemId()) {
                        case R.id.nav_home:
                            selectedFragment = new HomeFragment();
                            break;
                        case R.id.nav_dashboard:
                            selectedFragment = new DashBoardFragment();
                            break;
                        case R.id.nav_test_series:
                            selectedFragment = new TestSeriesFragment();
                            break;
                        case R.id.nav_doubt:
                            selectedFragment = new DoubtsFragment();
                            break;
                    }
 
                    getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
                            selectedFragment).commit();
 
                    return true;
                }
            };
}

TestSeriesFragment.java

package com.tecent.bottomnavigationviewexample;
 
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
 
 
public class TestSeriesFragmentextends Fragment {
 
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_test_series, container, false);
    }
}