导航抽屉紧靠操作栏前面和切换图标

Question

我希望这个问题不重复。我在Android Studio中创建了导航抽屉活动。但是当我打开抽屉时，导航视图关闭了Action Bar和Toggle图标的前面。

我的应用截图：

但我想这个观点：

因此，当打开抽屉时，必须看到操作栏和切换图标。我想在工具栏下方显示抽屉和抽屉切换图标

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="true"
    tools:openDrawer="start">

    <include
        layout="@layout/app_bar_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <android.support.design.widget.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:headerLayout="@layout/nav_header_main"
        android:fitsSystemWindows="true"
        style="@style/NavigationDrawerStyle"
        app:menu="@menu/activity_main_drawer" />

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

MainActivity.java

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {
    private NavigationView navigationView=null;
    private Toolbar toolbar=null;
    private DrawerLayout drawer;
    private Typeface robotoLight;

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


        robotoLight = Typeface.createFromAsset(getAssets(), "fonts/OpenSans-Regular.ttf");

        MainFragment fragment = new MainFragment();
        FragmentTransaction fragmentTransaction =
                getSupportFragmentManager().beginTransaction();
        fragmentTransaction.replace(R.id.fragment_container, fragment);
        fragmentTransaction.commit();


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


        drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close){

            @Override
            public void onDrawerOpened(View drawerView) {
                super.onDrawerOpened(drawerView);

                getSupportActionBar().setTitle("Homepage");

                invalidateOptionsMenu(); //
            }

            @Override
            public void onDrawerClosed(View drawerView) {
                super.onDrawerClosed(drawerView);

                getSupportActionBar().setTitle("Menu");
                invalidateOptionsMenu();
            }
        };

        toggle.syncState();

     /*   toggle.setDrawerIndicatorEnabled(false);

        toolbar.setNavigationIcon(R.drawable.ic_menu_slideshow);

        toolbar.setNavigationOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                drawer.openDrawer(Gravity.LEFT);
            }
        });*/
        drawer.setDrawerListener(toggle);


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

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.
        int id = item.getItemId();

        if (id == R.id.nav_home) {
            // Handle the camera action
            MainFragment fragment = new MainFragment();
            FragmentTransaction  fragmentTransaction =
                    getSupportFragmentManager().beginTransaction();
            fragmentTransaction.replace(R.id.fragment_container, fragment);
            fragmentTransaction.commit();


        } else if (id == R.id.nav_alarm_history) {
            AlarmFragment fragment = new AlarmFragment();
            FragmentTransaction  fragmentTransaction =
                    getSupportFragmentManager().beginTransaction();
            fragmentTransaction.replace(R.id.fragment_container, fragment);
            fragmentTransaction.commit();



        } else if (id == R.id.nav_sensors) {
            SensorFragment fragment = new SensorFragment();
            FragmentTransaction  fragmentTransaction =
                    getSupportFragmentManager().beginTransaction();
            fragmentTransaction.replace(R.id.fragment_container, fragment);
            fragmentTransaction.commit();

        } else if (id == R.id.nav_settings) {

            SettingsFragment fragment = new SettingsFragment();
            FragmentTransaction  fragmentTransaction =
                    getSupportFragmentManager().beginTransaction();
            fragmentTransaction.replace(R.id.fragment_container, fragment);
            fragmentTransaction.commit();

        }


        drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }
}

我该怎么做？谢谢