is back online!

On 28 March 2016 you may have received a “Bandwidth Limit Exceeded” error message when trying to access

This occurred because interest in tutorials on coding in MIT App Inventor is high! And the web server had exceeded the total bandwidth permitted for the month of March. I should have paid attention to the bandwidth logs and noticed sooner that I was closing in the bandwidth limit.

As soon as I learned about the problem, my Internet host (Tierpoint/ responded very quickly to increase my bandwidth to six times more than it was previously. Hopefully this will hold us for a few months! It costs me a bit more but I want to ensure you have access to the current content and more to come!


P.S. Tierpoint/ has been a great hosting provider for this and other web sites I have run for years, with excellent customer service. I am glad to put in a plug for them!

Using droid-at-screen to see your phone’s display on your computer

droid-at-screen is a free Java-based app that displays the content of your phone’s display to your computer’s display, when the phone is connected via a USB cable.

Below is a screen snap shot taken from my computer display. At the upper left is the Droid@Screen application running.  Droid@Screen is connected to my Nexus 5 phone.

At right is the display showing on my phone, which has been transferred from the phone to my computer over a USB connection. I’ve circled two user interface items – the magnifying glass icon is used to adjust the display size of the phone’s screen. Since the phone has a 1920×1080 display, the initial image is quite large!

Below that is a camera icon. Click on that to take a snapshot of what is on the screen, and then save the screen image to a local file.


At the lower left is the DroidAtScreen .jar file. This is the Java executable program file. Assuming Java is installed on your system, double click the .jar file to begin running Droid@Screen.

Continue reading Using droid-at-screen to see your phone’s display on your computer

Can you “gray out” a button until data entry is complete?

A reader asked  if it might be possible to “gray out” a button so that pressing it has no action, until appropriate data has been entered?

The answer is “Yes, we can do this.” After some thought, I came up with the following simple solution.

Update 1: Check the comments to this post for a reader’s great solution for doing this for Location services dependent function.

Update 2: Also, you can set the button component’s Enabled property to false, so that the button will not function. Then set Enabled to true once the data entry meets your app’s requirements.

User Interface

What we want to do is have the button look like it is “grayed out” and unusable until after some data is entered into the field. In the text box, I have set the  “hint” value to “Button available when data entered”:

Screenshot_20160317-202312After the user has entered some data, the button becomes “active” as shown here:


Continue reading Can you “gray out” a button until data entry is complete?

Thunkable turns programming into a drag-and-drop solution – based on App Inventor

Thunkable is a spin off of the MIT App Inventor project. If you can program in App Inventor, you can program in Thunkable. Their goal is to get the App Inventor concept running on both Android and iOS (iPhone).

Visit Thunkable at

Thunkable, built on top of the open-source project MIT App Inventor, is a visual programming tool

Source: Thunkable turns programming into a drag-and-drop solution – SD Times

There are indications that MIT App Inventor will focus on education and training applications and that spin offs will offer more powerful (and likely complex) features such as increased database functionality or media handling. These new features, oriented perhaps towards businesses and organizations (rather than education) might become a subscription service – but with added value in terms of features and capabilities.

More stuff coming soon …

Each week the past 3 weeks I thought I was going to have time to put together some new tutorials and post them, but “stuff happens” and I have not had time. I have a great list of tutorial suggestions that have come from readers and I really want to work on them and get them posted!

Sorry for the long delay!

In other news, I have completed the writing of Volume 4 of my App Inventor tutorial guide books. The book is now undergoing proof reading and final formatting. I hope to have it available as both an e-book and as a printed book.  I can now announce the title of the book “App Inventor: Graphics, Animation and Charts”. More details including a table of contents and sample pages as we get closer to release!