custom dialog android

MyDialog.java

public class MainActivity extends AppCompatActivity {

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

    public void showMyDialog(final Activity activity) {
        AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(activity);
        LayoutInflater inflater = activity.getLayoutInflater();
        final View dialogView = inflater.inflate(R.layout.my_custom_dialog, null);
        dialogBuilder.setView(dialogView);

        final TextView tvJudul = (TextView) dialogView.findViewById(R.id.tvTitle);
        tvJudul.setText("My Title");

        dialogBuilder.setTitle(activity.getString(R.string.setting_lang));
        dialogBuilder.setPositiveButton(activity.getString(R.string.act_ok), new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int whichButton) {
                int position = spinner1.getSelectedItemPosition();
                changeLang(activity, position);
            }
        });
//        dialogBuilder.setNegativeButton(activity.getString(R.string.setting_cancel), new DialogInterface.OnClickListener() {
//            public void onClick(DialogInterface dialog, int whichButton) {
//                dialog.dismiss();
//            }
//        });
        AlertDialog b = dialogBuilder.create();
        b.show();
        b.setCancelable(false);
    }
}