FrameLayout Shown Above AppBarLayout

Question

I have a simple CoordinatorLayout with a AppBarLayout and FrameLayout, but the FrameLayout contents are being displayed over the AppBarLayout regardless of the layout_behavior attribute on the FrameLayout. I've tried adding that attribute elsewhere (like on my RecyclerView), but it's the same behavior.

Here's a picture to show what I mean.

Activitiy Layout:

<?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="match_parent"
    android:fitsSystemWindows="true">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay"
            app:layout_scrollFlags="scroll|enterAlways"/>

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

    <FrameLayout
        android:id="@android:id/content"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"/>

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

Fragment Layout:

<android.support.v7.widget.RecyclerView
android:id="@+id/checkins_recycler_view"
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:scrollbars="vertical"
app:layout_behavior="@string/appbar_scrolling_view_behavior"/>

How I add my fragment in my Activity:

final UserCheckinsFragment fragment = new UserCheckinsFragment();
    final Bundle arguments = new Bundle();
    UserCheckinsFragment.getArguments(arguments, items);
    fragment.setArguments(arguments);

    getSupportFragmentManager().beginTransaction().add(android.R.id.content, fragment,
            UserCheckinsFragment.class.getName()).commit();

Answer 1

The FrameLayout ID (@android:id/content) in the xml and the container (android.R.id.content) in the Fragment transaction refer to the system root of layout, then it is laid over the all screen.

To solve, use them without android prefix.

Answer 2

add app:layout_behavior="@string/appbar_scrolling_view_behavior" to the RecyclerView and it will work. The app:layout_behavior should be to the root of the layout's of your Fragment