Скрыть панель приложений при прокрутке RecyclerView во фрагменте

Мой проект содержит макет activity_main.xml и 3 макета xml фрагментов в ViewPager. Фрагменты 2 и 3 ("help_us" и "беседа") содержат RecyclerView. Frgemnent 2 содержит линейный макет с EditText.

Я просто хочу скрыть AppBar при прокрутке Recyclerviews!

Я следовал этому руководству https://mzgreen.github.io/2015/06/23/How-to-hideshow-Toolbar-when-list-is-scrolling%28part3%29/ безрезультатно.

Итак, у меня есть два вопроса: 1- Что, черт возьми, я пропустил ??? (мне хочется плакать) 2- Когда я ввожу текст в EditText во фрагменте 2... угадайте, что? панель приложений рушится! и никогда не возвращается... Это явно нежелательное поведение...

Ладно, я грязный нуб. Но кто-нибудь видит, как я могу решить эти проблемы?

Вот мои макеты

Activity_main.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"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/background_black_matxxxhdpi"
    android:fitsSystemWindows="true"
    app:statusBarBackground="@android:color/transparent"
    tools:context="com.example.philipp.us.MainActivity">


    <android.support.v4.view.ViewPager
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="550dp"
        android:background="@drawable/background_black_logo_white_mediumxxxhdpi"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">

    </android.support.v4.view.ViewPager>

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:animateLayoutChanges="true"
        android:background="@android:color/transparent"
        android:paddingTop="@dimen/appbar_padding_top"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="56dp"
            android:layout_marginLeft="45dp"
            android:layout_marginRight="20dp"
            android:background="@android:color/transparent"
            android:elevation="4dp"
            app:layout_scrollFlags="scroll|enterAlways"
            app:popupTheme="@style/AppTheme.AppBarOverlay">

        </android.support.v7.widget.Toolbar>

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

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/submit_question"
        android:layout_width="76dp"
        android:layout_height="76dp"
        android:layout_gravity="top|center_horizontal"
        android:layout_marginEnd="10dp"
        android:background="@android:color/transparent"
        android:clickable="true"
        android:onClick="onSubmitQuestion"
        app:backgroundTint="@android:color/transparent"
        app:fabSize="normal"
        app:layout_anchor="@+id/container"
        app:layout_anchorGravity="bottom|right|center"
        app:srcCompat="@drawable/_btn_askus_normalxxxhdpi"
        app:useCompatPadding="true" />
</android.support.design.widget.CoordinatorLayout>`

фрагмент 2.xml

<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:layout_marginBottom="10dp"
android:background="@android:color/transparent"
android:focusableInTouchMode="true"
android:orientation="vertical"
android:weightSum="100"
tools:context="com.example.philipp.us.HelpUsFragment">


<FrameLayout
    android:layout_width="match_parent"
    android:layout_height="1dp"
    android:background="@color/white_transparent">

</FrameLayout>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="7"
    android:background="@android:color/transparent"
    android:paddingStart="8dp"
    android:weightSum="100">

    <ImageButton
        android:id="@+id/btn_localisation"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_marginBottom="5dp"
        android:layout_marginEnd="5dp"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:layout_marginStart="5dp"
        android:layout_marginTop="5dp"
        android:layout_weight="10"
        android:adjustViewBounds="true"
        android:background="@android:color/transparent"
        android:cropToPadding="false"
        android:onClick="onUpdateFilterLocation"
        android:scaleType="centerCrop"
        android:tint="@color/white_transparent"
        app:srcCompat="@drawable/custom_button_localisation_filter"
        tools:ignore="ContentDescription,NestedWeights" />

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_marginBottom="5dp"
        android:layout_marginEnd="10dp"
        android:layout_marginRight="10dp"
        android:layout_marginTop="5dp"
        android:layout_weight="20"
        android:background="@android:color/transparent"
        android:orientation="vertical"
        android:weightSum="100">

        <EditText
            android:id="@+id/lbl_filter_city"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="50"
            android:background="@android:color/transparent"
            android:ellipsize="end"
            android:gravity="center"
            android:hint="@string/hint_city_search"
            android:inputType="text|textCapWords|textAutoCorrect"
            android:lines="1"
            android:maxLines="1"
            android:minLines="1"
            android:scrollHorizontally="true"
            android:selectAllOnFocus="true"
            android:textAlignment="center"
            android:textColor="@color/white"
            android:textColorHint="@color/white_transparent"
            android:textColorLink="@color/colorHintText"
            android:textSize="12sp" />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="50"
            android:background="@android:color/transparent"
            android:elevation="0dp"
            android:gravity="center"
            android:orientation="horizontal"
            android:weightSum="100"
            tools:targetApi="lollipop">

            <EditText
                android:id="@+id/lbl_filter_value_radius"
                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:layout_weight="50"
                android:background="@android:color/transparent"
                android:hint="@string/hint_radius_filter_novalue"
                android:inputType="number"
                android:lines="1"
                android:maxEms="3"
                android:maxLength="3"
                android:maxLines="1"
                android:minLines="1"
                android:scrollHorizontally="true"
                android:selectAllOnFocus="true"
                android:textAlignment="viewEnd"
                android:textColor="@color/white"
                android:textSize="12sp" />

            <TextView
                android:id="@+id/lbl_unit_distance"
                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:layout_marginRight="3dp"
                android:layout_marginStart="3dp"
                android:layout_weight="50"
                android:background="@android:color/transparent"
                android:text="@string/unit_distance"
                android:textAlignment="textStart"
                android:textColor="@color/white_transparent"
                android:textSize="12sp" />
        </LinearLayout>

    </LinearLayout>

    <LinearLayout
        android:layout_width="1dp"
        android:layout_height="match_parent"
        android:background="@color/black"
        android:orientation="horizontal"
        android:visibility="gone">

    </LinearLayout>

    <EditText
        android:id="@+id/lbl_filter_keyword"
        style="@style/EditTextTheme"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_marginEnd="5dp"
        android:layout_weight="60"
        android:backgroundTint="@color/white_transparent"
        android:clipToPadding="true"
        android:digits="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZÄÖÜßäöüŒÀÂÇÈÉÊËÎÏÔÛÜœàâçèéêëîïôùûüáíóúñÑ-"
        android:gravity="center_vertical"
        android:hint="@string/hint_search_filter"
        android:imeOptions="actionSearch"
        android:inputType="textCapWords|textAutoCorrect"
        android:maxLines="1"
        android:minLines="1"
        android:paddingEnd="5dp"
        android:paddingStart="5dp"
        android:selectAllOnFocus="true"
        android:textColor="@color/white"
        android:textColorHint="@color/white_transparent"
        android:textSize="18sp" />

    <LinearLayout
        android:layout_width="1dp"
        android:layout_height="match_parent"
        android:background="@color/black"
        android:orientation="horizontal"
        android:visibility="gone">

    </LinearLayout>

    <ImageButton
        android:id="@+id/btn_filter_search"
        android:layout_width="18dp"
        android:layout_height="18dp"
        android:layout_gravity="center"
        android:layout_margin="5dp"
        android:layout_weight="10"
        android:background="@android:color/transparent"
        android:onClick="onFilterQuestions"
        android:scaleType="centerInside"
        android:tint="@color/white_transparent"
        app:srcCompat="@drawable/custom_button_search"
        tools:ignore="ContentDescription" />

</LinearLayout>

<android.support.v4.widget.SwipeRefreshLayout
    android:id="@+id/swiperefresh"
    android:layout_width="wrap_content"
    android:layout_height="0dp"
    android:layout_weight="93">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/question_recycler"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@android:color/transparent"
        android:fadingEdgeLength="10dp"
        android:isScrollContainer="false"
        android:requiresFadingEdge="vertical"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">

    </android.support.v7.widget.RecyclerView>
</android.support.v4.widget.SwipeRefreshLayout>

fragment 3.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:background="@android:color/transparent"
android:orientation="vertical"
android:weightSum="100"
tools:context=".ConversationFragment">

<FrameLayout
    android:layout_width="match_parent"
    android:layout_height="1dp"
    android:background="@color/white_transparent">

</FrameLayout>


<android.support.v7.widget.RecyclerView
    android:id="@+id/conv_recycler"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/transparent"
    android:fadingEdgeLength="10dp"
    android:paddingTop="10dp"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">

</android.support.v7.widget.RecyclerView>

Thank you very much