Move snackbar above the bottom bar

With the material components library you can use the setAnchorView method to make a Snackbar appear above a specific view.

In your case if you are using a BottomAppBar and a fab, you should define the fab in the setAanchorView. Something like:

FloatingActionButton fab = findViewById(R.id.fab);
Snackbar snackbar = Snackbar.make(view, "Snackbar over BottomAppBar", Snackbar.LENGTH_LONG);
snackbar.setAnchorView(fab);

The result:

With a BottomNavigationView you can define it as anchorView:

    Snackbar snackbar = Snackbar.make(view,"Snackbar over BottomNav",Snackbar.LENGTH_INDEFINITE);
    snackbar.setAnchorView(bottomNavigationView);
    snackbar.show();

Result:

replace your xml ->

<?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:id="@+id/main_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="test.tab_activity">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <android.support.v7.widget.Toolbar
            android:id="@+id/main_activity_toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:layout_scrollFlags="scroll|enterAlways">

        </android.support.v7.widget.Toolbar>

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



    <android.support.v4.view.ViewPager
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <android.support.design.widget.CoordinatorLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:id="@+id/placeSnackBar">

            <android.support.v4.view.ViewPager
                android:id="@+id/view_pager"
                android:layout_width="match_parent"
                android:layout_height="0dp"
                android:layout_weight="1" />

            <android.support.design.widget.FloatingActionButton
                android:id="@+id/fab"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="end|bottom"
                android:layout_margin="@dimen/fab_margin"
                android:src="@drawable/ic_menu_gallery" />

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

        <android.support.design.widget.TabLayout
            android:id="@+id/tab_layout"
            android:layout_width="match_parent"
            android:layout_height="56dp"
            android:background="?attr/colorPrimary" />

    </LinearLayout>

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

and The Snackbar code will be

Snackbar.make(findViewById(R.id.placeSnackBar), "Replace with your own action", Snackbar.LENGTH_LONG)
            .setAction("Action", null).show();

Assuming your are working with CoordinatorLayout you can modify the Snackbar's layoutparams before calling show(). By setting the anchorId and anchorGravity the snackBar will display above the bottom nav bar:

val layoutParams = snackbar.view.layoutParams as CoordinatorLayout.LayoutParams
layoutParams.anchorId = R.id.navigation //Id for your bottomNavBar or TabLayout
layoutParams.anchorGravity = Gravity.TOP
layoutParams.gravity = Gravity.TOP
snackbar.view.layoutParams = layoutParams

You can do this programmatically without cluttering your xml with extra CoordinatorLayouts by changing the snackbar's margins.

Java example:

Snackbar snack = Snackbar.make(findViewById(R.id.coordinatorLayout), 
    "Your message", Snackbar.LENGTH_LONG);
CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) 
    snack.getView().getLayoutParams();
params.setMargins(leftMargin, topMargin, rightMargin, bottomBar.height);
snack.getView().setLayoutParams(params);
snack.show();

Kotlin single line:

Snackbar.make(coordinatorLayout, "Your message", Snackbar.LENGTH_LONG).apply {view.layoutParams = (view.layoutParams as CoordinatorLayout.LayoutParams).apply {setMargins(leftMargin, topMargin, rightMargin, bottomBar.height)}}.show()