Styjun

I want to make my app bar to collapse like the youtube app, and i can't make it work. Please help, is there any missing code from there

The collapse toolbar will have tablayout below it, is it the reason that cause this?

<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.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:layout_width="match_parent"
 android:layout_height="match_parent"
 android:fitsSystemWindows="true"
 tools:context=".MainActivity">

 <com.google.android.material.appbar.AppBarLayout
 android:id="@+id/app_bar"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:theme="@style/AppTheme.AppBarOverlay"
 android:fitsSystemWindows="true"
 app:elevation="0dp">
 <com.google.android.material.appbar.CollapsingToolbarLayout
 android:id="@+id/collapsing_toolbar"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:fitsSystemWindows="true"
 app:contentScrim="?attr/colorPrimary"
 app:layout_scrollFlags="scroll|exitUntilCollapsed">

 <androidx.appcompat.widget.Toolbar
 android:id="@+id/toolbar"
 android:layout_width="match_parent"
 android:layout_height="?attr/actionBarSize"
 android:background="?attr/colorPrimary"
 app:layout_collapseMode="pin"
 app:popupTheme="@style/AppTheme.PopupOverlay" />

 </com.google.android.material.appbar.CollapsingToolbarLayout>

 <com.google.android.material.tabs.TabLayout
 android:id="@+id/tab_layout"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:background="?attr/colorPrimary"
 android:minHeight="?attr/actionBarSize"
 android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
 app:tabIndicatorColor="@color/colorAccent"
 app:tabSelectedTextColor="@color/skinColor" />

 </com.google.android.material.appbar.AppBarLayout>

 <androidx.viewpager.widget.ViewPager
 android:id="@+id/pager"
 android:layout_width="match_parent"
 android:layout_height="fill_parent"
 app:layout_behavior="@string/appbar_scrolling_view_behavior"
 android:background="@color/skinColor" />

</androidx.coordinatorlayout.widget.CoordinatorLayout>