fragment layout overlapping main activity's layout

Question

main activity 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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="com.example.apuroopa.homework5_apuroopa.ActionBar_Activity"
    android:id="@+id/container">

    <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" />

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

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

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"
        android:src="@android:drawable/ic_dialog_email" />

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

///cardview layout xml

 <?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:layout_margin="5dp"
    >


    <RelativeLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="#fffffff0"
        >


        <TextView
            android:id="@+id/title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textStyle="bold"
            android:layout_toRightOf="@+id/selection"

            android:layout_marginLeft="10dp"
            />
        <TextView
            android:id="@+id/description"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/title"
            android:layout_toLeftOf="@+id/image"

            android:layout_marginLeft="10dp"/>

        <CheckBox
            android:id="@+id/selection"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:focusable="false"
            android:clickable="false"
            android:layout_alignParentTop="true"
            android:layout_alignParentLeft="true"
            android:layout_alignTop="@id/title"
            />
        <ImageView
            android:id="@+id/image"
            android:layout_width="80dp"
            android:layout_height="100dp"
            android:layout_alignParentRight="true"
            android:scaleType="fitXY"/>
    </RelativeLayout>

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

///

 <?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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="com.example.apuroopa.homework5_apuroopa.ActionBarFragment">

    <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" />

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

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

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"
        android:src="@android:drawable/ic_dialog_email" />

    <android.support.v7.widget.RecyclerView
        android:id="@+id/cardList"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        />
</android.support.design.widget.CoordinatorLayout>


//Main Activity java 

public class ActionBar_Activity extends AppCompatActivity implements Fragment_RecyclerView.OnListItemSelectedListener
{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_action_bar_);
        Fragment mcontent =  Fragment_RecyclerView.newInstance(0);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        ActionBar actionBar=getSupportActionBar();
        Fragment_RecyclerView FR = new Fragment_RecyclerView();
        getSupportFragmentManager().beginTransaction().add(R.id.container,mcontent)
                //(Fragment_RecyclerView.newInstance(0)," ")
                .commit();
    }

I have a menu file inflated in activity. A Recyclerview fragment is added to the activity. Each row in recyclerview fragment consists of cardview layout. My recyclerview is overlapping the menu options as shown in the picture. The toolbar is placed above recyclerview in the layout file.

Answer 1

First give an id to android.support.design.widget.AppBarLayout

Then

<android.support.v7.widget.RecyclerView
    android:layout_below=@id/app_bar_layout_id/>

Answer 2

add app:layout_behavior="@string/appbar_scrolling_view_behavior" in cardview tag

Answer 3

Put CardView container in RelativeLayout:

 <RelativeLayout...>
     <android.support.v7.widget.CardView .....>
     </android.support.v7.widget.CardView>
</RelativeLayout>