我的侧边栏导航按钮不能移动

<androidx.drawerlayout.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"
    tools:context=".MainActivity">

    <!-- 主内容布局 -->
    <FrameLayout
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <!-- 侧边栏导航视图 -->
    <com.google.android.material.navigation.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:menu="@menu/drawer_menu" />

</androidx.drawerlayout.widget.DrawerLayout>

<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/nav_home"
        android:icon="@drawable/ic_home"
        android:title="Home" />
    <item
        android:id="@+id/nav_gallery"
        android:icon="@drawable/ic_gallery"
        android:title="Gallery" />
    <item
        android:id="@+id/nav_slideshow"
        android:icon="@drawable/ic_slideshow"
        android:title="Slideshow" />
</menu>

import android.os.Bundle;
import android.view.MenuItem;
import androidx.annotation.NonNull;
import androidx.appcompat.app.ActionBarDrawerToggle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.core.view.GravityCompat;
import androidx.drawerlayout.widget.DrawerLayout;
import com.google.android.material.navigation.NavigationView;

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    private DrawerLayout drawer;

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

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

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

        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this, drawer, toolbar,
                R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.addDrawerListener(toggle);
        toggle.syncState();

        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction().replace(R.id.content_frame,
                    new HomeFragment()).commit();
            navigationView.setCheckedItem(R.id.nav_home);
        }
    }

    @Override
    public void onBackPressed() {
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
        switch (item.getItemId()) {
            case R.id.nav_home:
                getSupportFragmentManager().beginTransaction().replace(R.id.content_frame,
                        new HomeFragment()).commit();
                break;
            case R.id.nav_gallery:
                getSupportFragmentManager().beginTransaction().replace(R.id.content_frame,
                        new GalleryFragment()).commit();
                break;
            case R.id.nav_slideshow:
                getSupportFragmentManager().beginTransaction().replace(R.id.content_frame,
                        new SlideshowFragment()).commit();
                break;
        }

        drawer.closeDrawer(GravityCompat.START);
        return true;
    }
}