<?xml version="1.0" encoding="utf-8"?>

 <menu xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto">

 <item android:title="Data"
    android:id="@+id/data"></item>
 <item android:title="Calibrate"
    android:id="@+id/calibrate"></item>
 <item android:title="Help"
    android:id="@+id/help"></item>

 </menu>

public void showPopup(View v) {
  PopupMenu popup = new PopupMenu(this, v);
  popup.inflate(R.menu.menu_main);
  popup.show();
}