Android - Remove shadow between Toolbar and TabLayout

Question

I'm trying to make a layout with CollapsingToolbarLayout. But I do not get one thing. I want to remove the shadow between Toolbar and TabLayout. I've tried several ways and I have not managed to remove the shadow. Can anybody help me? Thank you

<?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"
android:background="@android:color/white"
android:fitsSystemWindows="true">

<android.support.design.widget.CoordinatorLayout
    android:id="@+id/main_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_above="@+id/adview"
    android:fitsSystemWindows="true">

    <android.support.v4.view.ViewPager
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginTop="50dp"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

    <android.support.design.widget.TabLayout
        android:id="@+id/tabs"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_gravity="bottom"
        android:background="?attr/colorPrimary"
        android:translationZ="2dp"
        app:layout_anchor="@+id/appbar"
        app:layout_anchorGravity="bottom"
        app:tabGravity="fill"
        app:tabIndicatorColor="@android:color/white"
        app:tabIndicatorHeight="3dp"
        app:tabMode="fixed"
        app:tabTextColor="@color/tabs_text_selector" />

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="200dp"
        android:fitsSystemWindows="true"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <net.opacapp.multilinecollapsingtoolbar.CollapsingToolbarLayout
            android:id="@+id/collapsing_toolbar"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fitsSystemWindows="true"
            app:contentScrim="?attr/colorPrimary"
            app:expandedTitleMarginEnd="20dp"
            app:expandedTitleMarginStart="20dp"
            app:expandedTitleTextAppearance="@style/detalle_txt_expanded"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">

            <ImageView
                android:id="@+id/detalle_img"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:fitsSystemWindows="true"
                android:scaleType="centerCrop"
                android:src="@drawable/img_thumb_m"
                android:transitionName="@string/transition"
                app:layout_collapseMode="parallax"
                tools:targetApi="lollipop" />

            <ImageView
                android:id="@+id/detalle_img_tipo"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_margin="15dp"
                android:layout_gravity="center_horizontal"
                android:src="@drawable/img_edificio"/>

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:minHeight="?attr/actionBarSize"
                app:layout_collapseMode="pin"
                app:popupTheme="@style/AppTheme"/>

        </net.opacapp.multilinecollapsingtoolbar.CollapsingToolbarLayout>

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

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/detalle_info_fab_check"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        android:clickable="false"
        android:src="@drawable/ic_check1"
        app:fabSize="mini"
        app:backgroundTint="@android:color/white"
        app:layout_anchor="@+id/appbar"
        app:layout_anchorGravity="bottom|right|end" />

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

<include
    android:id="@+id/adview"
    layout="@layout/adview"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true" />

Answer 1

Try setting app:elevation="0dp" (not android:elevation) for your AppBarLayout.

In case you don't have the app namespace in your xml, add xmlns:app="http://schemas.android.com/apk/res-auto".

The difference between these two properties can be found here.

After that, check that you're not adding some background/border with any of these properties:

 <android.support.design.widget.TabLayout
    android:background="?attr/colorPrimary"
    android:translationZ="2dp"
    app:layout_anchor="@+id/appbar"
    app:layout_anchorGravity="bottom"
    app:tabGravity="fill"
    app:tabIndicatorColor="@android:color/white"/>

Or the theme you're using for the AppBarLayout.