login.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:orientation="vertical"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:background="@android:color/background_dark"
    android:layout_height="match_parent"
    android:padding="0dip"
    tools:context=".LoginActivity">
    <android.support.v7.widget.Toolbar
        android:elevation="4dp"
        android:background="@android:color/background_dark"
        android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize">
    </android.support.v7.widget.Toolbar>
    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <TextView
            android:gravity="center_horizontal"
            android:textSize="40sp"
            android:textColor="@android:color/white"
            android:text="Calling"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />

    </LinearLayout>
</LinearLayout>