新人使用DrawerLayout遇到一点小问题，求助大神

Question

没有显示Toolbar

代码如下：
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="match_parent"
>
android:layout_width="match_parent"
android:layout_height="match_parent">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light">
    </android.support.v7.widget.Toolbar>
</FrameLayout>
<TextView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="start"
    android:text="This is menu"
    android:textSize="30sp"
    android:background="#FFF"/>

Answer 1

<?xml version="1.0" encoding="utf-8"?>
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawerLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="48dp"
tools:openDrawer="start">

<!--主布局-->
<LinearLayout
    android:id="@+id/main_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

  <TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="start"
android:text="This is menu"
android:textSize="30sp"
android:background="#FFF"/>


</LinearLayout>


<!--侧滑菜单   -->
<LinearLayout
    android:id="@+id/drawer_root_layout"
    android:layout_width="200dp"
    android:layout_height="match_parent"
    android:layout_gravity="left"
    android:background="#60a980"
    android:gravity="center_horizontal"
    android:orientation="vertical">


</LinearLayout>