【Android Studio】How to Display Custom AlertDialog

MainActivity.java

package com.codingwithsara.customalertdialog;

import android.content.DialogInterface;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.TextView;

import org.w3c.dom.Text;

public class MainActivity extends AppCompatActivity {

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

    public void showAlertDialog(View view) {

        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Title");
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                // Do something
            }
        });

        LayoutInflater inflater = this.getLayoutInflater();
        View customAlertView = inflater.inflate(R.layout.custom_alert, null);
        builder.setView(customAlertView);

        TextView msg = customAlertView.findViewById(R.id.msg);
        msg.setText("Hello World!");

        AlertDialog alertDialog = builder.create();
        alertDialog.show();
    }
}