This web site is now receiving 25,000 unique visitors each month! I am very pleased that these tutorials are helpful to so many people all over the world!

Web site access is nearly the same every hour around the clock, implying a global readership (update: 145 countries!)

Operating System Used

  • 82% of the visitors use Windows
  • 7% use Linux
  • 4.4% use Mac OS X
  • 1% use iOS (iPhone/iPad)
  • A very tiny number have accessed the web site via Java Mobile, Blackberry and … the Nintendo Wii plus a few miscellaneous devices.


The web server output an average of about 800 kbytes per minute delivered to those viewing the web site. That is nearly 1 megabyte per minute.

Browser Used

  • Internet Explorer 42%
  • Chrome 32%
  • Firefox 12%
  • Opera 5%
  • Safari 2%
  • Android browser on smart phone 1/2%


I do not yet have a count of countries. I am working on that.

UPDATE: 145 countries!

How Do People Find

  • 67% come directly to the web site by typing the address or using a bookmark
  • About 1% come from a link on another web site
  • About 32% come from an online search, and almost all of those come from Google searches.

The most common search is for information about App Inventor (duh!), followed by information about Bluetooth! High in the search list are also searches for information on Android or App Inventor and Arduino and searches related to App Inventor sensors (such as orientation sensor) and TinyDB.

How Do We Know This?

When you visit any web site, your browser sends information about the operating system used, screen size, browser used, and so on, to the web site so the server can optionally deliver a web page customized to your configuration. When you search for something online, the search service (such as Google) passes the search text to the web server so web developers can optimize their content or learn what content is most desired by users.

The web server does not know who you are.

Using Location Information and GPS for finding your position

This tutorial introduces location services features available in App Inventor.

A future tutorial will demonstrate these features applied to specific applications.

About Android Device Location and GPS Features

Your Android device probably has built-in features to identify the device’s location. These features may include:

  • Global Positioning Satellite receiver (GPS)
  • Cellular network location information
  • Wi-Fi network location information

The GPS receiver interprets special (and very weak!) timing signals from satellites and uses those signals to compute latitude, longitude and altitude of your device. GPS has fairly good accuracy – correctly identifying the device’s position within as little as 5 meters (but which may at times be much wider such as within a 30 meter diameter circle accuracy). GPS accuracy is affected by the device’s ability to see the sky and may be blocked by buildings, trees and weather, and signals may suffer from ionospheric effects.

Cell phones can obtain information about the cellular network tower to which they are connected, including location information from the cellular tower.

Wi-Fi networks have a unique identifier associated with them (not the SSID public address). Google has built a map of wi-fi access point network locations using a combination of their Google mapping cars as well as everyone’s Android-powered cellular phone to build a huge database of wi-fi access points and their location. Your Android device can use a combination of location data and fetch a postal mailing address from Google for a given location.

Android phones have options as to which type of location information to use.

  • Cellular network information may be the least accurate, but it also uses the least amount of battery power.
  • Wi-fi network position information also uses little battery power, and can provide reasonably accurate location information when your phone is indoors and unable to hear signals from GPS satellites.
  • GPS provides the best accuracy but receiving and processing the signals uses the most battery power.

Your Android phone has options to select High accuracy, Battery saving and Device only.

  • High accuracy – Android will automatically select GPS, cellular or wi-fi to obtain a high accuracy position reading. This is likely the default setting on your phone.
  • Battery saving – Android will use cellular or Wi-fi networks to obtain position information.
  • Device only – Android will use the GPS receiver (greatest battery drain)

To select Location services, go to Settings | Location and set this feature to “On”.

Touch the item labeled “Mode” at the top of the screen to select “Location mode” options. This is where you may choose High accuracy, Battery saving or Device only.

Screenshot_20160516-175035To use any location features, you must turn Location to “On” in Android Settings!

MIT App Inventor has a component named LocationSensor providing access to latitude, longitude, altitude and even the postal mailing address associated with the location.

This tutorial introduces the LocationSensor and the basic properties and features. A future tutorial will go in to more depth.

Continue reading Using Location Information and GPS for finding your position

How to Add Your App Inventor App to the Google Play App Store

Last fall, I created a tutorial on adding App Inventor apps to the Google Play Store. That tutorial is still worth reading and is available here.

But I heard from readers that they would like more information about the process of adding an App Inventor app to the Google Play Store. I have created this new tutorial to help with that!

Also – I will soon add videos to accompany these tutorials. Was hoping to have a couple posted today but I have run out of time until next week to get those done.

Sign Up for a Google Play Developer Account

To add apps to the Google Play store, you need a Google Developer Account. Sign up is easy but it does involve a one time (good for life) application fee of US $25.

Go to to get started:


Follow the Google directions to set up your account.

Preparing Your App for the Google Play Store

Set the VersionNumber of Your App

In the Designer View, select the Screen1 component. At the bottom of Properties for Screen1, find the VersionCode and the VersionName items.

Continue reading How to Add Your App Inventor App to the Google Play App Store

Aligning the text that appears in ListPicker

Readers post questions on the FB page or the blog. Sometimes I can answer them but sometimes I cannot answer them right away. For those that I cannot answer, I add the question to a list of future tutorial ideas. If someone is not sure how to solve a problem, chances are that there are others who may need help with the same issue!

I am beginning to go through my list – watch for more tutorials based on reader questions. Note – I do not have time to solve specific or custom applications. I try to abstract the basic elements of the problem and create a generic solution that can apply to a wide variety of use cases.

ListPicker Text Alignment

A reader asked how to align the text that appears in the ListPicker box. The ListPicker displays a set of items on screen so that the user may select an item from the list. When the list appears on screen, all the items are “left justified” which means they appear on the left side of the screen.

To demonstrate, our ListPicker, below, displays a list of auto manufacturers:

Screenshot_20160502-115325Is there a way to center or right justify the items that appear in the ListPicker list like this? The first 4 items in this list are right justified and the last two are centered:

Screenshot_20160502-114442The answer to that question is basically “yes”, but it may not be perfect – as we will see.

Continue reading Aligning the text that appears in ListPicker