In build.gradle(app) in ‘dependencies’ add

implementation "com.google.android.material:material:1.2.0-alpha02"

I am a beginner in android development and I have encountered some difficulty in using the navigation drawer. I am developing an app with a navigation drawer on the left side. But when I add the navigation view to the xml file of the Main activity, it gives this error message:

Class referenced in the layout file, com.google.android.material.navigation.NavigationView, was not found in the project or the libraries 
Cannot resolve class com.google.android.material.navigation.NavigationView 

This is my code for the Main activity:

package com.hfad.catchat;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentTransaction;

import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

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

        Fragment fragment = new InboxFragment();
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        ft.add(R.id.content_frame, fragment);
        ft.commit();
    }
}

This is the xml file of the Main activity:

<?xml version="1.0" encoding="utf-8"?>
<androidx.drawerlayout.widget.DrawerLayout
    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" >

    <LinearLayout
        android_layout_width="match_parent"
        android_layout_height="match_parent"
        android_orientation="vertical" >

        <include
            layout="@layout/toolbar_main"
            android_id="@+id/toolbar" />

        <FrameLayout
            android_id="@+id/content_frame"
            android_layout_width="match_parent"
            android_layout_height="match_parent" />
    </LinearLayout>

    <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_headerLayout="@layout/nav_header"
        app_menu="@menu/menu_nav" />
</androidx.drawerlayout.widget.DrawerLayout>