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.

Capture

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.

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A “switch board” user interface panel for App Inventor apps

In the last post, we introduced some concepts for building “creative” App Inventor user interfaces that feature visually appealing user interface controls rather than the usual bland buttons.

In this post, we look at creating an array of toggle switches. Tapping a switch flips the switch from left to right, or right to left.

Concepts

In developing this user interface, we learn two concepts:

  1. We expand on the previous post and its use of images to create custom buttons.
  2. We see how a user interface control can be stored in a list and referenced like a variable within our apps.

Source code:

The User Interface

I called my app “Mission Control” because any good mission control panel needs lots of switches!

The user interface features 9 toggle switches in a 3 x 3 array. The purpose of this app is to demonstrate how to implement this type of interface – the app does not otherwise do anything interesting.

Tapping any toggle switch causes the switch lever to move to the other side of the switch. Here is a screen shot showing some toggle switches to the left and some to the right.

Screenshot_20160204-140323The Designer View

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Writing Android apps in Javascript

Another way to develop apps for Android is to write apps in the Javascript program scripting language (note – Javascript is not related to Java, in spite of the similar name). By using a special platform called Cordova, it is possible to package Javascript programs into a self contained Android .apk file that runs on the Android OS.

Even better – it is possible to package your Javascript app, using Cordova, into forms that run on iOS (iPhones and iPad) and Windows Phone too!

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MIT App Inventor “Extensions”

Some new “extension” features are available for testing in App Inventor at MIT App Inventor Extensions. The 4 extensions include vector addition, simple image processing, simple audio processing to identify the pitch of a sound, and the addition of multi-touch gestures to the Canvas.

I have not yet had time to try these but this is a sign of things to come as 3rd parties can begin to develop extensions to the core set of App Inventor features.

Look forward to trying these out! Click on the link above to take a look.

Free-Download App Inventor Location Sensor Cheat Sheet

Download here: App Inventor Location Sensor Cheat Sheet (PDF)

High res, suitable for printing. Feel free to share with others.

App Inventor sample source code: Location_WhereAmI.aia

Here is a GIF image but use the PDF for printing – also, where it says “enter a mailing address”, that should probably be “enter a street address”!

Voila_Capture 2015-10-28_12-21-17_PM

Post comments here or on our Facebook group page. Thank you!

E-Books and Printed Books

If you find these tutorials helpful (I hope you do!) please take a look at my books on App Inventor. To learn more about the books and where to get them (they are inexpensive) please see my App Inventor Books page.

  • App Inventor 2 Introduction (Volume 1 e-book)
    Step-by-step guide to easy Android programming
  • App Inventor 2 Advanced Concepts (Volume 2 e-book)
    Step-by-step guide to Advanced features including TinyDB
  • App Inventor 2 Databases and Files (Volume 3 e-book)
    Step-by-step TinyDB, TinyWebDB, Fusion Tables and Files
  • App Inventor 2 Graphics, Animation and Charts (Volume 4 e-book and printed book)
    Step-by-step guide to graphics, animation and charts

Thank you for visiting! — Ed

All new tutorial: Using TinyDB in App Inventor

I have completely rewritten and re-done my original tutorial on using TinyDB in App Inventor.

You can see the all new rewrite at Using TinyDB in App Inventor

TinyDB is a database used to store and retrieve values to semi-permanent storage on your phone or tablet. Unlike variables, which vanish when your app closes or your phone is turned off, values stored in the TinyDB are retained and can be accessed again, much later.

The original post was a popular post here on the blog, but it was brief and left out some details. I started over from scratch and wrote an all new, complete tutorial, with screen shots and blocks code, and downloadable App Inventor source code. Hope this helps!

E-Books and Printed Books

If you find these tutorials helpful (I hope you do!) please take a look at my books on App Inventor. To learn more about the books and where to get them (they are inexpensive) please see my App Inventor Books page.

  • App Inventor 2 Introduction (Volume 1 e-book)
    Step-by-step guide to easy Android programming
  • App Inventor 2 Advanced Concepts (Volume 2 e-book)
    Step-by-step guide to Advanced features including TinyDB
    • App Inventor 2 Databases and Files (Volume 3 e-book)
      Step-by-step TinyDB, TinyWebDB, Fusion Tables and Files
      Buy from: Amazon, Google Books, Kobo Books
  • App Inventor 2 Graphics, Animation and Charts (Volume 4 e-book and printed book)
    Step-by-step guide to graphics, animation and charts

Thank you for visiting! — Ed

FIRST Tech Challenge (Robotics) can now use App Inventor

Early in 2015, FIRST announced that the First Tech Challenge (FTC) robotics platform would be powered by the Qualcomm Snapdragon processor (the same processor used in most Android phones).

Starting with the Fall 2015 FTC competition, students can now control the robot using App Inventor. (Go here and page down to App Inventor Download and Resources and follow that link).

FTC uses a version of App Inventor that is installed on a local computer rather than running over the Internet, as we do with MIT App Inventor.

About FIRST

FIRST robotics is an “academic sport” for the mind as teams are faced with the challenge of conceptualizing, designing and building a complex robot to solve a challenge. The Mission of FIRST Robotics:

“Our mission is to inspire young people to be science and technology leaders, by engaging them in exciting mentor-based programs that build science, engineering and technology skills, that inspire innovation, and that foster well-rounded life capabilities including self-confidence, communication, and leadership.”

Volunteering

I am in my 8th year of volunteering as an engineering mentor to high school robotics teams. I am currently a volunteer with Glencoe High School’s Team #4488 “Shockwave” team where I am the lead mentor for Apps Software. Our team is a student-led team. The students make the design choices and implement the solutions. The mentors assist with technical and management training and specialized learning.

Our team, like many FIRST teams, is run similar to a business with separate sub-teams not only for robotics (mechanical, electrical, robot programming, CAD) but also other functions (marketing, business, strategy, web and applications software, graphic design) and even an animation team. Our applications team produces support software for the entire team by creating custom tablet apps and Windows applications software that assist in various information collection, analysis and processing functions. Last year, the team also created a robotics game that is available in the Google Play store.

There are many opportunities for volunteering – from technical engineering to business and marketing, graphic and art design, wood and metal working, CAD, and teaching. Visit usfirst.org to learn more!

Free-Download App Inventor Bluetooth Communications Cheat Sheet

Download here: App Inventor Bluetooth Cheat Sheet (PDF)

Covers basic Bluetooth text communications with links to tutorials on sending numeric and binary data, and connecting to Arduino over App Inventor Bluetooth.

App Inventor sample source code available here.

High res, suitable for printing. Feel free to share with others.

Here is a GIF image of the first page but use the PDF for printing (higher resolution) and it includes both pages:

Voila_Capture 2015-10-28_08-35-41_PM

Post comments here or on our Facebook group page. Thank you!

E-Books and Printed Books

If you find these tutorials helpful (I hope you do!) please take a look at my books on App Inventor. To learn more about the books and where to get them (they are inexpensive) please see my App Inventor Books page.

  • App Inventor 2 Introduction (Volume 1 e-book)
    Step-by-step guide to easy Android programming
  • App Inventor 2 Advanced Concepts (Volume 2 e-book)
    Step-by-step guide to Advanced features including TinyDB
  • App Inventor 2 Databases and Files (Volume 3 e-book)
    Step-by-step TinyDB, TinyWebDB, Fusion Tables and Files
  • App Inventor 2 Graphics, Animation and Charts (Volume 4 e-book and printed book)
    Step-by-step guide to graphics, animation and charts

Thank you for visiting! — Ed

Do you need to use a “real programming language” to create useful applications?

Do you need to use a “real programming language” to create useful applications?

No!

The history of programming begins long ago with the toggling of switches on a console to “program” a system. This primitive method advanced to the use of short text instructions called “assembly language”, which was then followed by programming languages such as Fortran and others.

In the past couple of decades, “real software” was often written in C/C++, Java or C#. Today, “real software” is written in PHP, Ruby on Rails, JavaScript, Python, VBA and other new programming languages and support libraries.

Yet there remains an attitude that real software is not real unless its written in a traditional programming language (Java, for example). There is a joke, especially among hardware designers, that “real programmers program in solder”!

So what is a “real programming language”? Realistically, any programming language or system that enables you to deliver a software project that meets the customer needs and requirements is a “real programming language”.

Which gets us to the main point – MIT App Inventor is a real programming language – it is just a different way of programming than that used by “traditional” solutions. Do not let others tell you that App Inventor is not real programming! (But it is more fun!)

Free-Download App Inventor OrientationSensor “Cheat Sheet”!

Download here: App Inventor Orientation Sensor Cheat Sheet (PDF)

High res, suitable for printing. Feel free to share with others.

Here is a GIF of the cheat sheet but use the PDF for printing (higher resolution):

Voila_Capture 2015-10-28_12-25-22_PM

Post comments here or on our Facebook group page. Thank you!

E-Books and Printed Books

If you find these tutorials helpful (I hope you do!) please take a look at my books on App Inventor. To learn more about the books and where to get them (they are inexpensive) please see my App Inventor Books page.

  • App Inventor 2 Introduction (Volume 1 e-book)
    Step-by-step guide to easy Android programming
  • App Inventor 2 Advanced Concepts (Volume 2 e-book)
    Step-by-step guide to Advanced features including TinyDB
  • App Inventor 2 Databases and Files (Volume 3 e-book)
    Step-by-step TinyDB, TinyWebDB, Fusion Tables and Files
  • App Inventor 2 Graphics, Animation and Charts (Volume 4 e-book and printed book)
    Step-by-step guide to graphics, animation and charts

Thank you for visiting! — Ed