Collapsing toolbar not collapsing when scrolled

Question

I am trying to implement collapsing toolbar in my android application. I am able to show the toolbar the way I want it to , but it is not collapsing when I scroll.

I am using below code

activity.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:fitsSystemWindows="true"
android:orientation="vertical"
tools:context=".MainActivity">

<include layout="@layout/main_toolbar" />

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">

    <com.gigamole.navigationtabstrip.NavigationTabStrip
        android:id="@+id/nts_strip"
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:background="@color/colorPrimary"
        android:elevation="4dp"
        app:nts_active_color="@color/white"
        app:nts_animation_duration="300"
        app:nts_color="@color/white"
        app:nts_corners_radius="1.5dp"
        app:nts_inactive_color="@color/white_transparent"
        app:nts_titles="@array/nts_titles" />

    <android.support.v4.view.ViewPager
        android:id="@+id/pager_photos"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:background="@color/white_transparent" />
</LinearLayout>
</LinearLayout>

main_toolbar.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"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_collapseMode="parallax"
android:orientation="vertical">

<android.support.design.widget.AppBarLayout
    android:id="@+id/appBar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

    <android.support.design.widget.CollapsingToolbarLayout
        android:id="@+id/collapsingToolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_scrollFlags="scroll|enterAlwaysCollapsed">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="@color/colorPrimary"
            app:layout_collapseMode="pin"
            app:layout_scrollFlags="scroll|enterAlways"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light">

            <TextView
                android:id="@+id/tv_toolbar_title"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:gravity="center_vertical"
                android:textAppearance="?android:attr/textAppearanceLarge"
                android:textColor="@color/white" />
        </android.support.v7.widget.Toolbar>
    </android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>

below is how the screen looks like

Answer 1

Add

app:layout_behavior="@string/appbar_scrolling_view_behavior"

for LinearLayout in activity.xml file.

Also add

app:layout_collapseMode="pin"
app:layout_scrollFlags="scroll|enterAlways"

for Toolbar