Develop Reference

Implementing app:hideOnScroll for BottomAppBar in Android

I have an app with the one Activity, many Fragments model, where several Fragments have a RecyclerView to show cards with content. I also have implemented the BottomAppBar from Material Design 2.0, and everything is fine except when the AppBar blocks the last CardView in the RecyclerView.
In terms of layout, I have a RecyclerView inside ConstraintLayout inside a Fragment, which sits in a FrameLayout in the main activity.
The documentation shows that for the BottomAppBar to be hidden on Scroll, we need to implement RecyclerView inside a NestedScrollView. There is one question here on SO where the answer has stated the same as well, but there seems to be no actual documentation or examples to demonstrate how this is to be done, except for this article on Medium, which uses the NestedScrollView in an Activity directly, holding a CoordinatorLayout which holds a ConstraintLayout.
Note: I think it also works on magic, because duplicating the layout in my fragment doesn't have any effect at all in my app.
How do I use NestedScrollView here?
PS : I need to have the TextView, as I set the RecyclerView to VISIBILITY.GONE and set the TextView to VISIBLE when I have no data to display.
Fragment Layout
<android.support.constraint.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:id="#+id/constraintLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="in.domain.APPNAME.Fragments.FragmentList">
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerViewIncident"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:paddingBottom="30dp"
android:visibility="visible"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0" />
<TextView
android:id="#+id/emptyView"
android:layout_width="wrap_content"
android:layout_height="17dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="No Incidents to display"
android:visibility="visible"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.503"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
Activity Layout
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
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"
android:id="#+id/uberLayout"
tools:context=".APPNAME">
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<FrameLayout
android:id="#+id/containerFrameLayout"
android:layout_width="match_parent"
android:layout_height="match_parent">
</FrameLayout>
</android.support.constraint.ConstraintLayout>
<android.support.design.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.bottomappbar.BottomAppBar
android:id="#+id/bottom_app_bar"
style="#style/Widget.MaterialComponents.BottomAppBar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
app:backgroundTint="#color/colorPrimary"
app:fabAlignmentMode="center"
app:navigationIcon="#drawable/baseline_menu_white_24dp"
app:hideOnScroll="true"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"
app:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
</android.support.design.bottomappbar.BottomAppBar>
<android.support.design.widget.FloatingActionButton
android:id="#+id/floatingActionButton"
android:layout_width="100dp"
android:layout_height="wrap_content"
android:clickable="true"
android:src="#drawable/baseline_add_white_24dp"
app:backgroundTint="#color/brightred"
app:fabSize="normal"
app:layout_anchor="#+id/bottom_app_bar"
tools:layout_editor_absoluteX="160dp"
tools:layout_editor_absoluteY="465dp" />
</android.support.design.widget.CoordinatorLayout>
</android.support.design.widget.CoordinatorLayout>

you shouldn't put the BottomAppBar and the FloatingActionButton in a separate CoordinatorLayout. Ditch the CoordinatorLayout they're in, the ConstraintLayout around your FrameLayout and that may already solve the problem.
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
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"
android:id="#+id/uberLayout"
tools:context=".APPNAME">
<FrameLayout
android:id="#+id/containerFrameLayout"
android:layout_width="match_parent"
android:layout_height="match_parent">
</FrameLayout>
<android.support.design.bottomappbar.BottomAppBar
android:id="#+id/bottom_app_bar"
style="#style/Widget.MaterialComponents.BottomAppBar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
app:backgroundTint="#color/colorPrimary"
app:fabAlignmentMode="center"
app:navigationIcon="#drawable/baseline_menu_white_24dp"
app:hideOnScroll="true"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"
app:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"/>
<android.support.design.widget.FloatingActionButton
android:id="#+id/floatingActionButton"
android:layout_width="100dp"
android:layout_height="wrap_content"
android:src="#drawable/baseline_add_white_24dp"
app:backgroundTint="#color/brightred"
app:fabSize="normal"
app:layout_anchor="#+id/bottom_app_bar" />
</android.support.design.widget.CoordinatorLayout>
I'm using a similar layout, the only difference being a <fragment> instead of a <FrameLayout>, and the BottomAppBar hides on scroll just fine. We don't need to use a NestedScrollView, if our scrolling content is a RecyclerView anyway, because RecyclerView implements NestedScrollingChild.
This interface should be implemented by View subclasses that wish to support dispatching nested scrolling operations to a cooperating parent ViewGroup.

Bottom Navigation with fab

I am currently working with BottomNavigationView and FloatingActionButton.
What i want to achieve is this below design:
And what i have tried:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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"
app:layout_insetEdge="bottom"
tools:context=".activity.BottomNavPrimary">
<android.support.design.widget.FloatingActionButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center|bottom" />
<android.support.design.widget.BottomNavigationView
android:id="#+id/bottomNavPrimary"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
app:layout_insetEdge="bottom"
android:background="?android:attr/windowBackground"
app:menu="#menu/bottom_nav_primary"></android.support.design.widget.BottomNavigationView>
</android.support.design.widget.CoordinatorLayout>

Your design looks as if you want to use the new BottomAppBar from the MaterialComponents that will fully be release with Android P. Especially if the left icon stands for a kind of side navigation it could be the right navigation element.
However, you have to be aware, that the elements on the left and right of the FAB have a different purpose than a bottom navigation. Instead of being entry points to "primary destinations" in an app, the BottomAppBar is defined as:
A bottom app bar displays navigation and key actions at the bottom of mobile screens.
So it is for page actions (like opening the dashboard or search). More explanation can be found in the design documentation.
I haven't had a chance to implement it yet (because I really needed it with a bottom navigation), but here is the code documentation example:
<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">
<!-- Other components and views -->
<com.google.android.material.bottomappbar.BottomAppBar
android:id="#+id/bar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
app:navigationIcon="#drawable/ic_menu_24"/>
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_anchor="#id/bar"/>
</android.support.design.widget.CoordinatorLayout>
So to me, it sounds as if you define your two page menu options and since the FAB is anchored to the bar it will push them to the sides.
The documentation also includes options for the optional FAB cradle that was shown during this year's Google I/O and shows how to handle menu and click handling.
Here is another useful link on how to set up gradle to include the new material components in your project.

I used this, to get something similar.
BottomNavigationView + FloatingActionButton
<androidx.constraintlayout.widget.ConstraintLayout xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="#+id/floating_button"
style="#style/Widget.MaterialComponents.FloatingActionButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="end"
android:layout_margin="16dp"
app:backgroundTint="#color/colorPrimaryLight"
app:elevation="#dimen/padding_10"
app:layout_constraintBottom_toTopOf="#id/navigation"
app:layout_constraintLeft_toRightOf="#id/navigation"
app:layout_constraintRight_toLeftOf="#id/navigation"
app:layout_constraintTop_toBottomOf="#id/navigation"
app:layout_constraintTop_toTopOf="#id/navigation"
app:layout_insetEdge="bottom"
app:srcCompat="#drawable/ic_add_black_24dp"
app:tint="#color/colorPrimary" />
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/navigation"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:background="#color/colorPrimaryDark"
android:visibility="visible"
app:itemIconTint="#drawable/bottom_navigation_icons"
app:itemTextColor="#drawable/bottom_navigation_icons"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:menu="#menu/navigation" />
</androidx.constraintlayout.widget.ConstraintLayout>

My solution simple and cool.
Parent layout must be a CoordinatorLayout and use BottomAppBar with FloatingActionButton as you can see below
<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.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">
<-- your other views -->
<com.google.android.material.bottomappbar.BottomAppBar
android:id="#+id/navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
app:backgroundTint="#color/colorPrimary">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<RelativeLayout
android:id="#+id/homePage"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintWidth_percent="0.4">
<androidx.appcompat.widget.AppCompatImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:src="#drawable/your_drawable"
android:padding="#dimen/small_margin"
app:tint="#color/white" />
</RelativeLayout>
<RelativeLayout
android:id="#+id/profile"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintWidth_percent="0.4">
<androidx.appcompat.widget.AppCompatImageView
android:layout_width="wrap_content"
android:padding="#dimen/small_margin"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:src="#drawable/your_drawable" />
</RelativeLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
</com.google.android.material.bottomappbar.BottomAppBar>
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="#+id/categories"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/your_drawable"
app:backgroundTint="#color/colorPrimary"
app:layout_anchor="#id/navigation"
app:tint="#android:color/white" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>
Result:

You could wrap your BottomNavigationView and your FloatingActionButton in a ConstraintLayout and use the following constraints on the FloatingActionButton:
app:layout_constraintTop_toBottomOf="#id/bottomNavPrimary"
app:layout_constraintBottom_toTopOf="#id/bottomNavPrimary"
app:layout_constraintLeft_toRightOf="#id/bottomNavPrimary"
app:layout_constraintRight_toLeftOf="#id/bottomNavPrimary"
This will center your FloatingActionButton vertically and horizontally relative to your BottomnavigationView
I hope that is what you asked for.
Final code would look something like this:
<android.support.design.widget.CoordinatorLayout android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<android.support.constraint.ConstraintLayout xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.FloatingActionButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintTop_toBottomOf="#id/bottomNavPrimary"
app:layout_constraintBottom_toTopOf="#id/bottomNavPrimary"
app:layout_constraintLeft_toRightOf="#id/bottomNavPrimary"
app:layout_constraintRight_toLeftOf="#id/bottomNavPrimary"/>
<android.support.design.widget.BottomNavigationView
android:id="#+id/bottomNavPrimary"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
app:layout_constraintBottom_toTopOf="parent"
android:background="?android:attr/windowBackground"
app:menu="#menu/bottom_nav_primary" />
</android.support.constraint.ConstraintLayout>

I think you can do this with bottomAppBar and embed some button inside that like below
<androidx.coordinatorlayout.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.google.android.material.bottomappbar.BottomAppBar
android:id="#+id/bottom_app_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
app:backgroundTint="#color/colorPrimary"
app:fabAlignmentMode="center"
app:fabAttached="true"
app:fabCradleDiameter="8dp"
style="#style/Widget.MaterialComponents.BottomAppBar"
app:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<ImageButton
android:id="#+id/btnReport"
android:layout_width="0dp"
android:layout_height="match_parent"
android:background="#android:color/transparent"
android:src="#drawable/ic_play"
android:layout_weight="1"
android:paddingRight="20dp"
/>
<ImageButton
android:id="#+id/btnPlayWords"
android:layout_width="0dp"
android:layout_height="match_parent"
android:background="#android:color/transparent"
android:src="#drawable/ic_show_chart"
android:layout_weight="1"
android:paddingLeft="20dp"
/>
</LinearLayout>
</com.google.android.material.bottomappbar.BottomAppBar>
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="#+id/fabAddWord"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/ic_add"
app:layout_anchor="#id/bottom_app_bar" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>

Hiding Toolbar when Scrolling a RecyclerView in nested Fragment

EDIT 2; This part of the code was OK. Check my answer for this, you might have a similar issue and I hope this solves your issue.
I've been checking a lot of posts with similar issues; they got me close, but I'm not able to make it right. I have a MainActivity, that hosts a Fragment loaded in the FrameLayout (id: fragment_container).
I want to hide the Toolbar when scrolling, but this only happens when I scroll the NavigationDrawer. When I scroll the RecyclerView, the Toolbar doesn't hide.
The Fragment contains a ViewPager, and each ViewPagerFragment has a RecyclerView.
I tried a lot of alternatives and this is the one that is closest to what I intend.
What I want to do:
hide toolbar when scrolling recycler view
What's going on right now:
http://gifmaker.cc/PlayGIFAnimation.php?folder=2016080211dGOklkBglH6HPrbVKq2rLE&file=output_lp5KmP.gif
My current main_activity layout:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:id="#+id/my_toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:elevation="16dp"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:layout_scrollFlags="scroll|enterAlways">
<Button
android:id="#+id/login_button"
android:layout_width="24dp"
android:layout_height="24dp"
android:layout_gravity="end"
android:layout_marginEnd="16dp"
android:layout_marginRight="16dp"
android:background="#drawable/ic_account_circle_white_24dp" />
<Button
android:id="#+id/favourites_button"
android:layout_width="24dp"
android:layout_height="24dp"
android:layout_gravity="end"
android:layout_marginEnd="16dp"
android:layout_marginRight="16dp"
android:background="#drawable/favourite_button" />
<Button
android:id="#+id/bookmarked_button"
android:layout_width="24dp"
android:layout_height="24dp"
android:layout_gravity="end"
android:layout_marginEnd="16dp"
android:layout_marginRight="16dp"
android:background="#drawable/bookmarked_button" />
<Button
android:id="#+id/history_button"
android:layout_width="24dp"
android:layout_height="24dp"
android:layout_gravity="end"
android:layout_marginEnd="16dp"
android:layout_marginRight="16dp"
android:background="#drawable/ic_history_white_24dp" />
</android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.DrawerLayout
android:id="#+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<FrameLayout
android:id="#+id/fragment_container"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<android.support.design.widget.NavigationView
android:id="#+id/navigationView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="start"
app:menu="#menu/menu" />
</android.support.v4.widget.DrawerLayout>
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab_pressed"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="16dp"
android:src="#drawable/favourite_button"
app:fabSize="mini"
app:layout_anchor="#id/fragment_container"
app:layout_anchorGravity="bottom|right|end" />
EDIT; for some reason the CoordinatorLayout is not being displayed in the code I just posted. Everything is surrounded with a CoordinatorLayout!
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/coordinatorLayout"
android:layout_width="match_parent"
android:layout_height="match_parent">
Previous Code goes here.
</android.support.design.widget.CoordinatorLayout>

My issue was inside the Fragment. I had this line that was killing the effect:
recyclerView.setNestedScrollingEnabled(false);
I removed it and now it works great. I've been dealing with this for so long, wish I got it earlier. Hope this helps someone out there.

RecyclerView gets pushed down when returned to activity

I'm having a really annoying problem. I have a recycler view inside my activity. The recycler view display a list of images taken by the camera. There is a FAB which takes you to the camera activity.
When I open this activity, the layout is perfect. But when I press the FAB and open the camera activity and return back, the recycler view gets pushed down to the centre of the screen.
Here is my layout:
<android.support.design.widget.CoordinatorLayout 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/coordinatorLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="test.nick.activities.ScansActivity">
<android.support.v7.widget.RecyclerView
android:id="#+id/listUnfinishedUploads"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="#dimen/layout_padding"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<include
android:id="#+id/app_bar"
layout="#layout/app_bar" />
</android.support.design.widget.AppBarLayout>
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|right"
android:layout_marginBottom="#dimen/fab_margin"
android:layout_marginRight="#dimen/fab_margin"
android:src="#drawable/scan_fab"
android:clickable="true"
app:fabSize="normal"
app:borderWidth="0dp"/>
<TextView
android:id="#+id/txtMsgs"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginLeft="#dimen/margin_left"
android:layout_marginRight="#dimen/margin_right"
android:visibility="gone" />
I'm stuck with this for 2 hours now :(
There is a coordinatorlayout closing tag as well but for some reason it is not displaying here.

Bottom navigation bar hides on trying scroll

I have Activity with bottom navigation bar (via roughike BottomBar library). It's look like this:
When i'm trying to scroll page, bottom bar hides automatically. So, I get this:
I want avoid this effect. I do not want hide bottom bar when I'm just trying to scroll content but all content lies on screen.
But if page contains content more than one screen then bottom bar must hides on scroll (and now it's works fine).
My code doesn't have any listeners for scroll and my xml file looks like this:
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".presentation.ui.mainactivity.MainActivity"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/mainCord" >
<android.support.design.widget.AppBarLayout
android:id="#+id/sliderContainer"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_height="?attr/actionBarSize"
android:layout_width="match_parent"
android:background="#color/primary"
android:theme="#style/ToolbarStyle"
app:titleTextAppearance="#style/ToolbarStyle" />
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:visibility="gone" />
<com.roughike.bottombar.BottomBar
android:id="#+id/bottomBar"
android:layout_width="match_parent"
android:layout_height="60dp"
android:layout_gravity="bottom"
app:bb_tabXmlResource="#xml/bottom_bar_tabs"
app:bb_activeTabColor="#color/white"
app:bb_inActiveTabColor="#color/bottom_bar_inactive_tab"
app:bb_inActiveTabAlpha="1"
app:bb_behavior="shy|shifting" />
</android.support.design.widget.CoordinatorLayout>
I'm looked for solution for my problem but found nothing. What can i do for avoid this effect?
UPDATED:
FAB is inside ViewPager. Layout for tab on screenshot look like this:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/eventCoordinatorLayout"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<android.support.v4.widget.SwipeRefreshLayout
android:id="#+id/refresh"
android:visibility="visible"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<android.support.v7.widget.RecyclerView
android:id="#+id/eventsRecyclerView"
android:scrollbars="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</android.support.v4.widget.SwipeRefreshLayout>
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity = "center"
android:gravity="center" >
<TextView
android:id="#+id/emptyText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#color/secondary_text"
android:textSize="16sp"
android:gravity="center"
android:text="#string/empty_events_text"
android:drawableTop="#drawable/ic_no_calendar"
android:drawablePadding="4dp"
android:visibility="gone" />
<TextView
android:id="#+id/createEventText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/create_event_text"
android:textColor="#color/secondary_text"
android:textSize="16sp"
android:visibility="gone" />
<TextView
android:id="#+id/createEventButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#color/primary"
android:text="#string/create_event"
android:textSize="16sp"
android:visibility="gone" />
</LinearLayout>
<android.support.design.widget.FloatingActionButton
android:id="#+id/createEvent"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:src="#drawable/ic_add_white_24dp"
style="#style/floating_action_button"
app:layout_anchor="#id/eventsRecyclerView"
app:layout_anchorGravity="bottom|end"
app:borderWidth="0dp"
app:elevation="6dp"
app:pressedTranslationZ="12dp" />
<RelativeLayout
android:id="#+id/loadingPanel"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center" >
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:indeterminate="true" />
</RelativeLayout>
</android.support.design.widget.CoordinatorLayout>

app:bb_behavior="underNavbar"
You have an issue in the following code
<com.roughike.bottombar.BottomBar
android:id="#+id/bottomBar"
android:layout_width="match_parent"
android:layout_height="60dp"
android:layout_gravity="bottom"
app:bb_tabXmlResource="#xml/bottom_bar_tabs"
app:bb_activeTabColor="#color/white"
app:bb_inActiveTabColor="#color/bottom_bar_inactive_tab"
app:bb_inActiveTabAlpha="1"
app:bb_behavior="shy|shifting" />
replace the
app:bb_behavior="shy|shifting"
with
app:bb_behavior="underNavbar"
Hope this works for you!

Check your manifest FILE and make sure you're not using full screen theme...However, you can use the following code to hide and show the bar on android higher than API 19. To hide the bar, just change VISIBLE to GONE, and make sure you call the showNavBar() method in both your onCreate() and onResume() method
public void showNavBar() {
View view = getWindow().getDecorView();
view.setSystemUiVisibility(View.VISIBLE);
}

I had the same issue, I fixed it by doing this:
In activity_main.xml add this to the CoordinatorLayout:
android:fitsSystemWindows="true"
The viewpager should be like this:
<android.support.v4.view.ViewPager
android:background="#color/colorPrimary"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
And in all your Fragments, they should start with NestedScrollView and must contain (fillViewport):
<android.support.v4.widget.NestedScrollView 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/constraintLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true"
tools:context="com.khan.junaid.phonefans.MainActivity">
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/fans_list_view"
/>
</android.support.v4.widget.NestedScrollView>
These settings will make the fragments scrollable, and the content will no more be hiding behind the Navigation bar buttons.