Implementing Bottom Navigation Bar in your Android App with more than 3 items

activity_main.xml

<android.support.design.widget.CoordinatorLayout 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"
    android:fitsSystemWindows="true">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:theme="@style/ThemeOverlay.AppCompat.Dark">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            app:layout_scrollFlags="scroll|enterAlways"
            app:contentInsetStart="@dimen/fab_margin"/>

    </android.support.design.widget.AppBarLayout>

    <FrameLayout
        android:id="@+id/content"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"/>

    <android.support.design.widget.BottomNavigationView
        android:id="@+id/navigation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:background="?android:attr/windowBackground"
        app:menu="@menu/navigation" />
</android.support.design.widget.CoordinatorLayout>

MainActivity.java

public class MainActivity extends AppCompatActivity {

    @BindView(R.id.navigation)
    BottomNavigationView navigation;
    @BindView(R.id.toolbar)
    Toolbar toolbar;

    private int saveState;

    private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
            = new BottomNavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(MenuItem item) {
            Fragment selectedFragment = null;
            switch (item.getItemId()) {
                case R.id.navigation_home:
                    selectedFragment = MapFragment.newInstance();
                    break;
                case R.id.navigation_dashboard:
                    selectedFragment = EventFragment.newInstance();
                    break;
                case R.id.navigation_notifications:
                    selectedFragment = UserFragment.newInstance();
                    break;
                case R.id.navigation_world:
                    selectedFragment = WorldFragment.newInstance();
                    break;
                case R.id.navigation_deal:
                    selectedFragment = DealFragment.newInstance();
                    break;

            }
            BottomNavigationViewHelper.disableShiftMode(navigation);
            FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
            transaction.replace(R.id.content, selectedFragment);
            transaction.commit();
            return true;
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);
        BottomNavigationViewHelper.disableShiftMode(navigation);
        navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
        setSupportActionBar(toolbar);

        int check = getIntent().getIntExtra("check", R.id.navigation_home);

        if (savedInstanceState != null) {
            navigation.setSelectedItemId(saveState);
        } else {
            FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
            switch (check) {
                case R.id.navigation_home:
                    transaction.replace(R.id.content, MapFragment.newInstance());
                    break;
                case R.id.navigation_notifications:
                    transaction.replace(R.id.content, UserFragment.newInstance());
                    break;
                case R.id.navigation_dashboard:
                    transaction.replace(R.id.content, EventFragment.newInstance());
                    break;
                case R.id.navigation_world:
                    transaction.replace(R.id.content, WorldFragment.newInstance());
                    break;
                case R.id.navigation_deal:
                    transaction.replace(R.id.content, DealFragment.newInstance());
                    break;

            }
            transaction.commit();
            navigation.setSelectedItemId(check);
        }
    }
  
    @Override
    protected void onResume() {
        super.onResume();
        navigation.setSelectedItemId(saveState);
    }

    @Override
    public void onSaveInstanceState(Bundle outState, PersistableBundle outPersistentState) {
        super.onSaveInstanceState(outState, outPersistentState);
        saveState = navigation.getSelectedItemId();
    }
}

progaurd-rules.pro

-keepclassmembers class android.support.design.internal.BottomNavigationMenuView {
    boolean mShiftingMode;
}