title: Error: attribute 'package:contentScrim' not found
body: <p>While I am trying to do Collapsing Toolbar Layout I got the error on contentScrim not found.
      This is my XML file.</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;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/htab_maincontent"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:fitsSystemWindows="true"&gt;
  
      &lt;android.support.design.widget.AppBarLayout
          android:id="@+id/htab_appbar"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:background="?attr/colorPrimary"
          android:fitsSystemWindows="true"
          android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"&gt;
  
          &lt;android.support.design.widget.CollapsingToolbarLayout
          android:id="@+id/htab_collapse_toolbar"
          android:layout_width="match_parent"
          android:layout_height="256dp"
          android:fitsSystemWindows="true"
          app:contentScrim="?attr/colorPrimary"
          app:layout_scrollFlags="scroll|exitUntilCollapsed|snap"
          app:titleEnabled="false"&gt;
  
          &lt;ImageView
              android:id="@+id/htab_header"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:background="@drawable/header"
              android:fitsSystemWindows="true"
              android:scaleType="centerCrop"
              app:layout_collapseMode="parallax"/&gt;
  
          &lt;View
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:alpha="0.3"
              android:background="@android:color/black"
              android:fitsSystemWindows="true"/&gt;
  
          &lt;android.support.v7.widget.Toolbar
              android:id="@+id/htab_toolbar"
              android:layout_width="match_parent"
              android:layout_height="?attr/actionBarSize"
              android:layout_gravity="top"
              android:layout_marginBottom="48dp"
              app:layout_collapseMode="pin"
              app:popupTheme="@style/ThemeOverlay.AppCompat.Light"/&gt;
  
          &lt;android.support.design.widget.TabLayout
              android:id="@+id/htab_tabs"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:layout_gravity="bottom"
              app:tabIndicatorColor="@android:color/white"
              app:tabSelectedTextColor="@android:color/white"
              app:tabTextColor="@color/white_70"/&gt;
  
      &lt;/android.support.design.widget.CollapsingToolbarLayout&gt;
  
      &lt;/android.support.design.widget.AppBarLayout&gt;
  
      &lt;android.support.v4.view.ViewPager
          android:id="@+id/htab_viewpager"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          app:layout_behavior="@string/appbar_scrolling_view_behavior"/&gt;
  
  &lt;/android.support.design.widget.CoordinatorLayout&gt;
  </code></pre>
  
  <p>I have seen all the tutorial on GitHub and other sites. and used but I could not get the solution. Any easy way to the parallax sticky header for the fragment. and right now I am following the code of <a href="https://android.jlelse.eu/parallax-scrolling-header-tabs-android-tutorial-2cc6e40aa257" rel="noreferrer">https://android.jlelse.eu/parallax-scrolling-header-tabs-android-tutorial-2cc6e40aa257</a> and see the documentation of android developer about the CollapsingToolbarLayout.</p>