片段容器不会填充父级

Question

正如你们在图片中看到的那样，我的片段容器超出了智能手机屏幕，但其高度设置为fill_parent，其中包含的所有内容（自定义视图和抽屉布局）也都是fill_parent。难道我的片段不应该填充其父母吗？

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="fill_parent">

    <android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="fill_parent"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        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.s.MainActivity">

        <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="wrap_content"
                app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
                app:layout_scrollFlags="scroll|enterAlways|snap"
                android:background="#6495ED"
                />
            <android.support.design.widget.TabLayout
                android:id="@+id/tabs"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="#6495ED"
                />
        </android.support.design.widget.AppBarLayout>

        <android.support.v4.view.ViewPager
            android:layout_width="match_parent"
            android:layout_height="fill_parent"
            android:id="@+id/fragment_container"
            app:layout_behavior="@string/appbar_scrolling_view_behavior"
            android:layout_below="@+id/appbar">

        </android.support.v4.view.ViewPager>
    </android.support.design.widget.CoordinatorLayout>
    <android.support.design.widget.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:fitsSystemWindows="true"
        app:headerLayout="@layout/nav_header_nav"
        app:menu="@menu/activity_nav_drawer" />

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