Smooth View Pager - AppBar with Fragment

activity_smooth_view_pager.xml

<?xml version="1.0" encoding="utf-8"?><!--
  ~ Copyright 2016 "Henry Tao <hi@henrytao.me>"
  ~
  ~ Licensed under the Apache License, Version 2.0 (the "License");
  ~ you may not use this file except in compliance with the License.
  ~ You may obtain a copy of the License at
  ~
  ~     http://www.apache.org/licenses/LICENSE-2.0
  ~
  ~ Unless required by applicable law or agreed to in writing, software
  ~ distributed under the License is distributed on an "AS IS" BASIS,
  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  ~ See the License for the specific language governing permissions and
  ~ limitations under the License.
  -->

<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/coordinator"
  android:layout_width="match_parent"
  android:layout_height="match_parent">

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

  <me.henrytao.smoothappbarlayout.SmoothAppBarLayout
    android:id="@+id/smooth_app_bar_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:minHeight="2dp">

    <FrameLayout
        android:id="@+id/header_fragment_placeholder"
        app:layout_scrollFlags="scroll"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <android.support.v7.widget.Toolbar
      android:id="@+id/toolbar"
      android:background="@android:color/transparent"
      app:layout_scrollFlags="scroll|enterAlways"
      app:navigationIcon="@drawable/ic_toolbar_arrow_back"
      style="@style/AppStyle.MdToolbar" />

    <android.support.design.widget.TabLayout
      android:id="@+id/tab_layout"
      android:layout_width="match_parent"
      android:layout_height="wrap_content" />
  </me.henrytao.smoothappbarlayout.SmoothAppBarLayout>
</android.support.design.widget.CoordinatorLayout>

ex_header_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:orientation="vertical"
	android:layout_width="match_parent"
	android:layout_height="wrap_content">

	<TextView
		android:id="@+id/title"
		android:text="Hello World"
		android:layout_width="match_parent"
		android:layout_height="120dp" />

</LinearLayout>

ExHeaderFragment.java

package me.henrytao.smoothappbarlayoutdemo.fragment;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import me.henrytao.smoothappbarlayoutdemo.R;

public class ExHeaderFragment extends Fragment {
  public static final String TAG_EX_HEADER = "fragment_blog_header";

	@Override
	public View onCreateView(final LayoutInflater inflater, final ViewGroup vg, final Bundle data) {
		super.onCreateView(inflater, vg, data);
		return inflater.inflate(R.layout.ex_header_fragment, vg, false);
	}
}

SmoothViewPagerActivity.java

@Override
protected void onCreate(Bundle savedInstanceState) {
  // ...all the other code
  createOrGetBlogHeaderFragment(savedInstanceState);
}

protected ExHeaderFragment createOrGetBlogHeaderFragment(@Nullable final Bundle savedInstanceState) {
    final ExHeaderFragment exHeaderFragment;

    if (savedInstanceState == null) {
      exHeaderFragment = new ExHeaderFragment();
      exHeaderFragment.setArguments(getIntent().getExtras());

      new Handler().postDelayed(new Runnable() {
        @Override
        public void run() {
          getSupportFragmentManager()
                  .beginTransaction()
                  .replace(R.id.header_fragment_placeholder, exHeaderFragment, ExHeaderFragment.TAG_EX_HEADER)
                  .commit();
        }
      }, 3000);
    } else {
      exHeaderFragment = (ExHeaderFragment) getSupportFragmentManager().findFragmentByTag(ExHeaderFragment.TAG_EX_HEADER);
    }

    return exHeaderFragment;
  }

Gif: https://media.giphy.com/media/1x7qw0P0Fw6vm/giphy.gif