如何修复添加NavigationView

Question

我正在尝试将导航视图从NavigationView模式添加到现有代码中。在模拟器上运行该应用会崩溃。

我添加了此模式中的所有内容，但它在行drawer.addDrawerListener(toggle);上向我显示了错误

  

原因：java.lang.NullPointerException：尝试在空对象引用上调用虚拟方法'void android.support.v4.widget.DrawerLayout.addDrawerListener（android.support.v4.widget.DrawerLayout $ DrawerListener）'

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home);

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.addDrawerListener(toggle);// HERE ERROR
        toggle.syncState();

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


    //         Create the adapter that will return a fragment for each of the three
    //         primary sections of the activity.
        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());



        mSectionsPagerAdapter.addItem(new NowFragment(), "Сейчас в прокате");
        mSectionsPagerAdapter.addItem(new SoonFragment(), "Скоро в прокате");
        mSectionsPagerAdapter.addItem(new TicketsFragment(), "Билеты");

        // Set up the ViewPager with the sections adapter.
        mViewPager = (ViewPager) findViewById(R.id.container);
        mViewPager.setAdapter(mSectionsPagerAdapter);

        TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);

        mViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
        tabLayout.addOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(mViewPager));
        tabLayout.setupWithViewPager(mViewPager);

    }

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:id="@+id/main_content"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true"
        tools:context=".ui.HomeActivity">

        <android.support.design.widget.AppBarLayout
            android:id="@+id/appbar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:paddingTop="@dimen/appbar_padding_top"
            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:layout_weight="1"
                android:background="?attr/colorPrimary"
                app:layout_scrollFlags="scroll|enterAlways"
                app:popupTheme="@style/AppTheme.PopupOverlay"
                app:title="@string/app_name">

            </android.support.v7.widget.Toolbar>

            <android.support.design.widget.TabLayout
                android:id="@+id/tabs"
                android:layout_width="match_parent"
                android:layout_height="wrap_content">

                <android.support.design.widget.TabItem
                    android:id="@+id/tabItem"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@string/tab_text_1" />

                <android.support.design.widget.TabItem
                    android:id="@+id/tabItem2"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@string/tab_text_2" />

                <android.support.design.widget.TabItem
                    android:id="@+id/tabItem3"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@string/tab_text_3" />

            </android.support.design.widget.TabLayout>
        </android.support.design.widget.AppBarLayout>

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

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