Hide toolbar in activity by scrolling a recyclerview inside the Fragment?

Question

My Activity XML is

<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/drawer"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <android.support.design.widget.AppBarLayout
            android:id="@+id/appbar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="@color/colorPrimary"
                android:title="@string/app_name"
                app:layout_scrollFlags="scroll|enterAlways"/>
        </android.support.design.widget.AppBarLayout>

        <FrameLayout
            android:id="@+id/fragmentContainer"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            />

    </LinearLayout>


    <android.support.design.widget.NavigationView
        android:id="@+id/drawerNavigationView"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:itemTextColor="@color/navview_text_color"
        app:menu="@menu/home_drawer_items_menu"/>
</android.support.v4.widget.DrawerLayout>

My Fragment XML is :

  <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="match_parent">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <android.support.design.widget.TabLayout
            android:id="@+id/tabs"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_scrollFlags="scroll|enterAlways"/>

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

    <android.support.v4.view.ViewPager
        android:id="@+id/viewPager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@android:color/black"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"/>

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="@dimen/fab_margin"
        android:clickable="true"
        android:src="@drawable/ic_plus"
        android:tint="@android:color/white"
        app:elevation="5dp"
        app:layout_anchor="@id/viewPager"
        app:layout_anchorGravity="bottom|right|end"/>
</android.support.design.widget.CoordinatorLayout>

My fragment uses tabs and nested fragments inside the ViewPager and my activity uses navigation drawer so i can't move the tabs to activity as the tabs are only needed for this specific fragment. And other fragments just need a toolbar. At the same time all the fragments need to access the navigation drawer.

Now what i want to do is somehow associate app:layout_scrollFlags="scroll|enterAlways" with my activity's toolbar. So that whenever i scroll my RecyclerView inside the fragment the toolbar in the activity gets hidden.

It would be great if you guys can point me in the right direction or help me figure out how to do this ?

Answer 1

I have solved this issue, though there is still room for some minor improvements like the FAB is moving up and down whenever i scroll RecyclerView inside the Fragment

In order to make toolbar respond to app:layout_scrollFlags="scroll|enterAlways" this is what i did

I changed my Activity XML to:

<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/drawer"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true">

    <android.support.design.widget.CoordinatorLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <android.support.design.widget.AppBarLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="@color/colorPrimary"
                android:title="@string/app_name"
                app:layout_scrollFlags="scroll|enterAlways"/>
        </android.support.design.widget.AppBarLayout>

        <FrameLayout
            android:id="@+id/fragmentContainer"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_behavior="@string/appbar_scrolling_view_behavior"
            />
    </android.support.design.widget.CoordinatorLayout>


    <android.support.design.widget.NavigationView
        android:id="@+id/drawerNavigationView"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:itemTextColor="@color/navview_text_color"
        app:menu="@menu/home_drawer_items_menu"/>
</android.support.v4.widget.DrawerLayout>

Also i changed my Fragment XML to:

<LinearLayout
    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="match_parent"
    android:orientation="vertical">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="0">

        <android.support.design.widget.TabLayout
            android:id="@+id/tabs"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>

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

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1">

        <android.support.v4.view.ViewPager
            android:id="@+id/viewPager"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@android:color/black"/>

        <android.support.design.widget.FloatingActionButton
            android:id="@+id/fab"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:layout_alignParentEnd="true"
            android:layout_alignParentRight="true"
            android:layout_marginBottom="60dp"
            android:layout_marginEnd="20dp"
            android:layout_marginRight="20dp"
            android:clickable="true"
            android:src="@drawable/ic_plus"
            android:tint="@android:color/white"
            app:elevation="5dp"/>
    </RelativeLayout>
</LinearLayout>