Tag Archives: android

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

Free – download MIT App Inventor “Cheat Sheet”

I have created a “cheat sheet” that captures all of the App Inventor components, blocks, events, properties and procedure calls. The “cheat sheet” is 9 page of details, in a large (almost 5 MB) PDF file that contains high resolution images suitable for high res printing. For those learning App Inventor, the cheat sheet may help you quickly find various components within the interface.

Download here: App Inventor Cheat Sheet (PDF)

Feel free to share with others.

I have some ideas for additional cheat sheets but would like to hear what you might like to have in a “cheat sheet” summary format. 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

How to Place Your App Inventor Apps in the Google Play Store

An all new tutorial on this subject is available here as of May 2016! There is still some great information below – read both!

Apps you create in App Inventor may be added to the Google Play Store.

The process is not difficult but there are many steps to the process and you will need to create some graphic images to illustrate and promote your app in the store.

Summary of the Steps

  • Set your app’s VersionCode and VersionName.
  • Apply for a Google Developer account (one time fee of US $25 after which you can upload an unlimited number of apps, forever).
  • Create at least two and up to 8 screenshots of your app for display in the store’s app listing.
  • Create a “feature graphic” and a high resolution icon for use in the store listing.
  • Use the App Inventor provided keystore file, or use a keystore file you have created elsewhere or previously.
  • Build and export your app as a .apk file to your computer.
  • Create a title for your app in the store
  • Write a description for your app to appear in the store
  • Decide on free versus paid (paid requires a “merchant account” to be set up).
  • Upload your apk file, keystore file, image files and title and description, and provide some additional information (such as product category, pricing, and target audience).

Continue reading How to Place Your App Inventor Apps in the Google Play Store

App Inventor course available in Spanish

Estructurado en 8 módulos y con más de 146 clases este curso es ideal para aquellas personas que, sin tener idea de programación, quieren tener un curso completo de App Inventor paso a paso y basado en la metodología de aprender haciendo.

Curso de Desarrollo de aplicaciones móviles Android con App Inventor

The 22 hour online course is offered through the udemy.com

(I did not make clear – sorry – this course is from Professor José Luis Núñez and he is offering it through udemy.com. I am not involved in this at all – just sharing the link – Ed)

App Inventor introduces copy and paste of code blocks!

App Inventor has introduced “copy and paste” of code blocks. Now you can copy blocks of code within a current screen, or from one screen to another screen, or even between projects. This is great news!

Look for the “backpack” icon at upper right of the blocks Viewer screen:

AI_Copy1

Select a block or blocks with the mouse pointer, and then click and drag the selected blocks into the backpack. A copy of the blocks are placed into the backpack and your original blocks also remain in the editing window.

Click on the backpack icon and it displays the code blocks currently stored in the backpack:

AI_Copy2

Click on the code block in the backpack (at right) and drag it into the Blocks Viewer. That is all you need to do to copy blocks.

Use this feature to copy blocks within your current screen, or to copy blocks from one screen to another screen, or to copy blocks from one app to another app.

You can put several blocks into the backpack, and then select only the ones you wish to copy over to another blocks Viewer.

How do you empty the backpack? It seems the only way to empty the backpack of saved items is to close the editing windows, go back to the MIT App Inventor home page (http://appinventor.mit.edu/) and select the Create apps! button to re-enter the designer and blocks editor.

Regardless, this is a GREAT NEW FEATURE! Thanks MIT App Inventor team!

Implementing an “Array” in App Inventor

What is an “Array”?

An array is a variable data type that stores a collection of values referenced by an index number.

For example, suppose we wished to store the names of the 12 months of the year: January, February, March, … , November, December so we can convert a month number to a text name. Month 1 converts to “January”, Month 2 converts to “February” and Month 12 converts to “December”.

An easy way to do this conversion is to set up an array that, in concept, looks something like this:

Month[1] = “January”
Month[2] = “February”
Month[3] = “March”
Month[4] = “April”
Month[5] = “May”
Month[6] = “June”
Month[7] = “July”
Month[8] = “August”
Month[9] = “September”
Month[10] = “October”
Month[11] = “November”
Month[12] = “December”

Month is the name of this variable – but unlike other variables, this one stores 12 separate values. Each value is referenced by using an index – if the index value is 2, then Month[index] refers to “February”.

If we have a date, such as (US-style) – 2/14/15, meaning February 15, 2015, we can convert the month number of 2, into the text month name by referencing Month[2].

If you have studied algebra math or beyond, you have encountered array variables such as X1, X2, X3, … Xn where the value Xi is read as “X subscript i”. This is the same concept as an array of values. If you have not studied algebra, this notation may be new to you. 

Most programming languages support an array variable type but App Inventor does not support arrays. Yet arrays are a convenient way of storing and working with some types of data. To support an array-like variable in App Inventor, we can use a list and map the array subscript to an index position in the list.  By hiding this within a couple of procedures, we can simulate the array variable type.

Sample User Interface

I created a simple app to demonstrate the use and implementation of the array. You can download this app from the MIT App Inventor Gallery here.

Continue reading Implementing an “Array” in App Inventor

How to use the “2 Button” Notifier dialog box

A reader asked, “When using the 2 button Notifier dialog, how do we know which button was pressed?

The 2 button Notifier dialog alert box displays 3 buttons(!) – the first two have values you specify, such as “Ok” and “Done”, as shown here, and the third is an optional generic “Cancel” button:

Screenshot_2015-09-11-15-07-15

The Notifier component block is a procedure call that has no return value – so how can you determine which button was selected?

The answer is that the selected button is returned to a separate event handler.

Continue reading How to use the “2 Button” Notifier dialog box