Alert Dialog Builder

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

public class MainActivity extends AppCompatActivity {

    private Button mybutton;
    private AlertDialog.Builder dialog;

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

        mybutton = findViewById(R.id.buttonLayout);

        mybutton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {


                // Create dialog
                // Criar o dialog
                dialog = new AlertDialog.Builder(MainActivity.this);

                // Dialog Title
                // Titulo da dialog
                dialog.setTitle("Title of dialog");

                // Dialog Mesage
                // Mensagem da dialog
                dialog.setMessage("Dialog Message blá, blá, blá ?");

                // Not possible to cancel
                // Caixa obrigatoria não cancelável
                dialog.setCancelable(false);

                // Put ant icon in the dialog
                // Colocar um icon na caixa de dialogo
                dialog.setIcon(android.R.drawable.ic_dialog_info);

                // Creat positive and negative answer
                // Criar resposta positiva e negativa
                dialog.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        Toast.makeText(MainActivity.this, "Yes pressed", Toast.LENGTH_LONG).show();
                    }
                });
                dialog.setNegativeButton("No", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        Toast.makeText(MainActivity.this, "No pressed", Toast.LENGTH_LONG).show();
                    }
                });

                // Mont dialog box
                // Montar a dialog
                dialog.create();
                dialog.show();
            }
        });
    }
}