How to correctly implement view content behind statusbar when using fragments

Question

I'm trying put my ImageBackdrop from the collapsing toolbar behind the statusBar, I've done it right with the Drawer and the navigationView but I can't do it with my fragments, In the cheesequare demo, Chris did it, and I can do it that way, but it's not using a single activity app and fragment transitions, so that's not quite what I'm looking for.

My style:

 <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>

    </style>

My v21 Style:

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>

        <item name="android:windowDrawsSystemBarBackgrounds">true</item>
        <item name="android:statusBarColor">@android:color/transparent</item>
    </style>

My Main Activity:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
    android:id="@+id/drawer_layout"
    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:fitsSystemWindows="true">

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

    <android.support.design.widget.NavigationView
        android:id="@+id/navigationView"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:background="@color/window_background_white"
        android:fitsSystemWindows="true"
        app:headerLayout="@layout/nav_header"
        app:itemTextColor="@color/title_text_color"
        app:menu="@menu/drawer_menu"/>

</android.support.v4.widget.DrawerLayout>

My content_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    android:id="@+id/fragment_container"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

My fragment:

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    style="@style/AppTheme.CoordinatorLayout"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:fitsSystemWindows="true">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbarLayout"
        android:layout_width="match_parent"
        android:layout_height="@dimen/detail_backdrop_height"
        android:fitsSystemWindows="true"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/collapsing_toolbar"
            android:layout_width="match_parent"
            android:layout_height="@dimen/detail_backdrop_height"
            android:fitsSystemWindows="true"
            app:collapsedTitleTextAppearance="@style/AppTheme.CollapsingToolbar.Text.Transparent"
            app:contentScrim="?attr/colorPrimaryDark"
            app:expandedTitleMarginEnd="64dp"
            app:expandedTitleMarginStart="48dp"
            app:expandedTitleTextAppearance="@style/AppTheme.CollapsingToolbar.Text.Transparent"
            app:layout_scrollFlags="scroll|enterAlwaysCollapsed|enterAlways"
            app:title="">

                <ImageView
                    android:id="@+id/imageView_backdrop"
                    android:layout_width="match_parent"
                    android:layout_height="@dimen/detail_backdrop_height"
                    android:adjustViewBounds="true"
                    android:fitsSystemWindows="true"
                    android:scaleType="centerCrop"
                    app:layout_collapseMode="parallax"/>


                <TextView
                    android:id="@+id/textView_expanded_title"
                    style="@style/AppTheme.CollapsingToolbar.TextView.Multiline"

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                app:layout_collapseMode="pin"
                app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
                app:titleTextColor="@color/colorAccent"/>


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

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

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerView"
        style="@style/AppTheme.RecyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_gravity="fill_vertical"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"/>

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

Another Fragment where I don't need the content behind

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    style="@style/AppTheme.CoordinatorLayout"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:fitsSystemWindows="true">


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

        <android.support.design.widget.TabLayout
            android:id="@+id/about_tabLayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:tabGravity="fill"/>

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


    <ViewSwitcher
        android:id="@+id/viewSwitcher"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">

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

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

    </ViewSwitcher>


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

What I've accomplished:

If I put android:fitsSystemWindows="false" in the DrawerLayout I can accomplish the desired effect in the fragment where I have the CollapsingToolbar but in the ViewPager I've a strange grey statusBar.

Desired effect accomplished badly with android:fitsSystemWindows="false" in the drawerLayout:

But in the second fragment the content it's behind the statusBar, where I don't want it.

What I've read:

StackOverflow,

Medium

Answer 1

Ok the problem was the content_main.xml it's always replaced so I thought it wasn't necessary to have the android:fitsSystemWindows attribute but i was wrong, adding android:fitsSystemWindows="true" solved the problem.

snippet content_main:

    <?xml version="1.0" encoding="utf-8"?>
    <android.support.design.widget.CoordinatorLayout
    android:id="@+id/fragment_container"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"/>

Important: if like me after that you find a bug in viewPager when coordinatorLayout has android:fitsSystemWindows="true" take a look here: CoordinatorLayout status bar padding disappears from ViewPager 2nd page