How to implement bottom navigation tab as per the google new guideline

Here first custom solution as far as I know.

UPDATE:

Official BottomNavigationView is out in Support lib 25.

You can use the support library v25.

Add in your build.gradle

compile 'com.android.support:design:25.0.0'

Add the BottomNavigationView in your layout:

<android.support.design.widget.BottomNavigationView        android:id="@+id/bottom_navigation"        app:menu="@menu/bottom_navigation_menu"        android:layout_width="match_parent"        android:layout_height="wrap_content"        app:itemBackground="@color/colorPrimary"        app:itemIconTint="@color/mycolor"        app:itemTextColor="@color/mycolor"/>

Then create a menu file (menu/bottom_navigation_menu.xml):

<?xml version="1.0" encoding="utf-8"?><menu xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto">    <item        android:id="@+id/my_action1"        android:enabled="true"        android:icon="@drawable/my_drawable"        android:title="@string/text"        app:showAsAction="ifRoom" />    ....</menu>

Then add the listener:

BottomNavigationView bottomNavigationView = (BottomNavigationView)                findViewById(R.id.bottom_navigation);bottomNavigationView.setOnNavigationItemSelectedListener(        new BottomNavigationView.OnNavigationItemSelectedListener() {            @Override            public boolean onNavigationItemSelected(@NonNull MenuItem item) {                switch (item.getItemId()) {                    case R.id.my_action1:                        //Do something...                        break;                }                return false;            }        });

Now, BottomNavigationView is added in design support lib v25.0.0 released on October 2016

Add BottomNavigationView into your xml file.

For ex. 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:id="@+id/activity_main"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context="priyank.patel.bottomnavigationdemo.MainActivity">    <FrameLayout        android:id="@+id/main_container"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:layout_above="@+id/bottom_navigation"        android:layout_alignParentTop="true">    </FrameLayout>    <android.support.design.widget.BottomNavigationView        android:id="@+id/bottom_navigation"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentBottom="true"        app:itemBackground="@color/colorPrimary"        app:itemIconTint="@android:color/white"        app:itemTextColor="@android:color/white"        app:menu="@menu/bottom_navigation_main" /></RelativeLayout>

Add xml for menu items into menu folder.

For ex. bottom_navigation_main.xml

<?xml version="1.0" encoding="utf-8"?><menu xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto">    <item        android:id="@+id/action_favorites"        android:enabled="true"        android:icon="@drawable/ic_favorite_white_24dp"        android:title="@string/text_favorites"        app:showAsAction="ifRoom" />    <item        android:id="@+id/action_video"        android:enabled="true"        android:icon="@drawable/ic_music_video_white_24dp"        android:title="@string/text_video"        app:showAsAction="ifRoom" />    <item        android:id="@+id/action_music"        android:enabled="true"        android:icon="@drawable/ic_audiotrack_white_24dp"        android:title="@string/text_music"        app:showAsAction="ifRoom" /></menu>

Set OnNavigationItemSelectedListener on BottomNavigationView in your activity class.

For ex. MainActivity.java

import android.support.design.widget.BottomNavigationView;import android.support.v4.app.Fragment;import android.support.v4.app.FragmentManager;import android.support.v4.app.FragmentTransaction;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.MenuItem;public class MainActivity extends AppCompatActivity {private Fragment fragment;private FragmentManager fragmentManager;@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    fragmentManager = getSupportFragmentManager();    fragment = new FavouriteFragment();    final FragmentTransaction transaction = fragmentManager.beginTransaction();    transaction.add(R.id.main_container, fragment).commit();    BottomNavigationView bottomNavigationView = (BottomNavigationView)            findViewById(R.id.bottom_navigation);    bottomNavigationView.setOnNavigationItemSelectedListener(            new BottomNavigationView.OnNavigationItemSelectedListener() {                @Override                public boolean onNavigationItemSelected(MenuItem item) {                    switch (item.getItemId()) {                        case R.id.action_favorites:                            fragment = new FavouriteFragment();                            break;                        case R.id.action_video:                            fragment = new VideoFragment();                            break;                        case R.id.action_music:                            fragment = new MusicFragment();                            break;                    }                    final FragmentTransaction transaction = fragmentManager.beginTransaction();                    transaction.replace(R.id.main_container, fragment).commit();                    return true;                }            });    }}

Checkout here for BottomNavigation-Demo