滑动菜单始终全屏

Question

我试图使滑动菜单全屏显示，但我不能。

如果我使用 android：fitsSystemWindows =“ false” ，它就像照片中的第一张照片。

如果我使用 android：fitsSystemWindows =“ true” ，那就像照片中的第二张照片。滑动菜单位于ActionBar下。

但是我想显示菜单，就像照片中的第三张照片一样。我该怎么做？我应该改变什么？

nav_header_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/view_container"
    android:background="@color/colorPrimary"
    android:layout_width="match_parent"
    android:layout_height="160dp"
    android:gravity="bottom"
    android:orientation="vertical"
    android:theme="@style/ThemeOverlay.AppCompat.Dark">

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:orientation="vertical"
        android:padding="@dimen/padding_nav_activity_horizontal">

        <ImageView
            android:layout_width="75dp"
            android:layout_height="75dp"
            android:paddingTop="@dimen/padding_nav_activity_vertical"
            android:contentDescription="@null"
            app:srcCompat="@mipmap/ic_launcher" />

        <TextView
            android:id="@+id/nav_header_main_app_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:paddingTop="@dimen/padding_nav_header_vertical_spacing"
            android:text="@string/app_name"
            android:textAppearance="@style/TextAppearance.AppCompat.Body1" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/app_version" />
    </LinearLayout>
</RelativeLayout>

activity_main.xml

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="false"
    tools:context=".MainActivity"
    tools:openDrawer="start">

    <RelativeLayout
        android:id="@+id/main_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <android.support.design.widget.TabLayout
            android:id="@+id/tab_layout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="?attr/colorPrimary"
            android:minHeight="?attr/actionBarSize"
            android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
            app:tabMode="scrollable"/>

        <android.support.v4.view.ViewPager
            android:id="@+id/view_pager"
            android:layout_width="match_parent"
            android:layout_height="fill_parent"
            android:layout_below="@id/tab_layout"/>
    </RelativeLayout>

    <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_main"
        app:menu="@menu/activity_main_drawer" />
</android.support.v4.widget.DrawerLayout>

MainActivity.java

    private ActionBarDrawerToggle toggle;
    private DrawerLayout drawer;
    private NavigationView navigationView;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        toggle = new ActionBarDrawerToggle(
                this, drawer, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.setDrawerListener(toggle);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setHomeButtonEnabled(true);
        toggle.syncState();

        navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);
    }

    public boolean onOptionsItemSelected(final MenuItem item) {

        if (toggle.onOptionsItemSelected(item)){
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    public boolean onNavigationItemSelected(@NonNull MenuItem item) {

        switch (item.getItemId()) {
            case R.id.nav_item_1:
                return true;
        }
        return true;
    }

    public void onBackPressed() {
        assert drawer != null;
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }
}