Why does my fragment shows additional bar below the toolbar?

Question

I have added the corresponding content and activity.xml as well. When I run the app in android studio on my phone, I don't see this additional bar there. But still I am wondering why am I seeing this when I open it in my editor ?

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/content_home"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.a.a2.HomeFragment"
    tools:showIn="@layout/activity_home">

</RelativeLayout>

activity_home.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.a.a2.Home">

    <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_home" />

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

content_home.xml

<fragment 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/fragment"
    android:name="com.a.a2.HomeFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:layout="@layout/fragment_home" />

home.java

public class Home extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_snd_number_home);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_snd_number_home,menu);
        return true;
    }
}

styles.xml

<resources xmlns:android="http://schemas.android.com/tools" xmlns:app="urn:oasis:names:tc:xliff:document:1.2">

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/actionMenuTextColor</item>
        <item name="@android:windowLightStatusBar">true</item>
    </style>

    <style name="AppTheme.NoActionBar">
        <item name="windowActionBar">false</item>
        <item name="windowNoTitle">true</item>
    </style>

    <style name="MyToolbar" parent="ThemeOverlay.AppCompat.Dark.ActionBar">
        <item name="android:textColorPrimary">#000000</item>
    </style>

    <style name="ToolbarTitle" parent="@style/TextAppearance.Widget.AppCompat.Toolbar.Title">
        <item name="android:textSize">20sp</item>
    </style>

    <style name="AppTheme.AppBarOverlay" parent="ThemeOverlay.AppCompat.Dark.ActionBar" />

    <style name="AppTheme.PopupOverlay" parent="ThemeOverlay.AppCompat.Light" />

    <style name="onOffSwitch" parent="Theme.AppCompat.Light">
        <!-- active thumb & track color (30% transparency) -->
        <item name="colorControlActivated">#000000</item>

        <item name="colorControlNormal">#9E9E9E</item>

        <!-- inactive thumb color -->
        <item name="colorSwitchThumbNormal">#9E9E9E</item>

        <!-- inactive track color (30% transparency) -->
        <item name="android:colorForeground">#42221f1f</item>
    </style>
</resources>

Answer 1

Edit your styles.xml as

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">

Answer 2

Use Below Style, This is working for me :

 <!-- Base application theme. -->
    <style name="AppTheme" parent="Base.Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorPrimary</item>
        <item name="windowActionBar">false</item>
        <item name="windowNoTitle">true</item>
    </style>

Answer 3

Change your theme in the editor same as that of your manifest for the activity that you are working on and that should fix your problem.