Tag Archives: programming

App Inventor News, Components

MIT begins testing “App Inventor Extension Components”

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MIT has begun testing a new App Inventor feature that will enable developers to create their own “extension components”. Extension components are written in Java. Once created and tested, these new components may be shared with other App Inventor developers for use in programs.

What this means: if App Inventor lacks a feature or capability, then a Java developer familiar with App Inventor and its components software development kit will be able to add new features to App Inventor. Over time, the capabilities and power of App Inventor are likely to grow enormously – and rapidly. The ability to extend App Inventor’s features/components is an exciting and tremendously important development for the future of App Inventor!

For now, this feature is in “test mode”.

Source: App Inventor Extension Components available for testing | Explore MIT App Inventor

Components, General

App Inventor Stores Numbers as “Floating Point” Format

When you type a number, such as “123”, computers convert the text values of “123” into an internal representation used by the computer. There are many possible ways that numbers can be represented inside a computer. For example, the computer could:

  • keep numbers in their original text format “123” (decimal format)
  • convert them into a binary representation (binary integers)
  • a “floating point” representation (floating point or “float” format)
  • or even a “binary coded decimal” (BCD) representation.

Each internal format has benefits and drawbacks, depending on the application. Most computers (and programming systems) convert entered numbers from their original text format into either integer format or floating-point number format.

App Inventor converts values to floating point format. Which is fine, except that you will encounter some odd and subtle issues. As the link below notes, in App Inventor arithmetic, 0.3 + 0.6 does not equal 0.9!

Continue reading App Inventor Stores Numbers as “Floating Point” Format →

Documentation, General, Products, STEM Education

App Inventor 2 Tutorial Volume 2 is now available at Amazon

Volume 2 of the App Inventor 2 Tutorial is now available at Amazon as an e-book via this link: App Inventor 2 Tutorial Volume 2: Step-by-step: Advanced features including TinyDB.  The e-book will also be available from Google Play shortly.

Description

MIT App Inventor 2 is a fast and simple way to create custom Android apps for smart phones or tablets. Volume 2 in the series introduces debugging methods, explains additional controls not covered in Volume 1, introduces “agile” methods for developing a real world app, and provides sample code for using the TinyDB database.

The App Inventor 2 Tutorial series is targeted at adult learners (high school and up). App Inventor 2 provides a simplified “drag and drop” interface to layout your app’s screen design. Then implement the app’s behavior with “drag and drop” programming blocks to quickly assemble a program in a graphical interface.

Volume 1 of this series covered the basics of the App Inventor user interface Designer and the Blocks programming editor, plus basic “blocks” programming concepts and tools for arithmetic, text processing, event handling, lists and other features. Volume 2 builds upon Volume 1 to provide tips on debugging programs when the apps work incorrectly, how to use hidden editing features, and how to install your own apps on to your phone or tablet for general use. Code samples are provided for using the Notifier component for general use or for debugging, for user interface control tricks such as buttons that change color continuously or implementing the missing “radio buttons” component, using ListPicker and Spinner for list selections, and using the WebViewer to display web pages in your app. The book includes a large section on designing and building a sample real world application and finishes with a chapter on using the TinyDB database.

For readers of the blog, Chapters 4–8 are based on the tutorial already presented here. Chapter 2 and Chapter 9 on TinyDB are all new material.

Chapters

  • Introduction
  • Chapter 1 – App Inventor Tips
  • Chapter 2 – Debugging App Inventor Programs
  • Chapter 3 – User Interface Control Tricks
  • Chapter 4 – Designing and Building a Real World Application
  • Chapter 5 – Tip Calculator Version 2
  • Chapter 6 – Tip Calculator Version 3
  • Chapter 7 – Tip Calculator Version 4
  • Chapter 8 – Tip Calculator Version 5
  • Chapter 9 – Using the TinyDB database

(Volume 3 is now available – App Inventor 2 Databases and Files adds substantially more information on TinyDB, plus TinyWebDB and Fusion Tables and includes the full introduction to TinyDB).

AppInventor_Volume2Cover

Products, Programming Method, Software, STEM Education

“Visual Development” system for Arduino

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As you know, MIT App Inventor is a graphical-based programming system, or a “visual development” system where programs are constructed by dragging and dropping “blocks” onto a Blocks editor.

Arduino, which we mentioned in conjunction with our Bluetooth interface code, is a microcontroller system that is normally programmed in a language similar to the C++ programming language – which is text-based.

Mitov Softwware has introduced a new visual programming system for Arduino. I have not yet had a chance to try this out – the software is in “Beta” test phase and is not yet generally available.

The simplicity of an App Inventor type programming environment might then be available for Arduino applications. This is very exciting. It may be helpful for enabling more kinds of people, with different types of backgrounds than software developers(!) to write code for Arduino boards.

Program Arduino boards visually, fast and easy with Visuino #Visuino #Arduino

Source: Visuino – Visual Development for Arduino by Mitov Software

I have used this screen shot from their web site to illustrate the general idea – really looking forward to trying this out!

screenshot-03

App Inventor News

App Inventor Classic (version 1) to Shut Down on July 15 

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Most users are already using AI 2 and are unaffected by this change. But if you are still using AI Classic (version 1), then this message is very important – please click through the link to read the full story!

May 24, 2015 — MIT App Inventor Classic will shut down on July 15, 2015. After July 15, 2015, you will not be able to access or edit your existing AI Classic projects. It will be impossible to create new AI Classic projects.This shutdown applies only to AI Classic (AI1). App Inventor 2 (AI2) will not be affected.

MIT will not automatically convert your AI1 projects to AI2 projects. But MIT will provide a conversion tool that will help you convert the AI projects that are important to you into AI2 projects. We expect to release this converter in about 2 weeks (i.e., around June 8).

Source: App Inventor Classic to Shut Down on July 15 | Explore MIT App Inventor

How do you know which version you are using?
Login to App Inventor and create or open a project. If the URL address in your browser begins with
http://ai2.appinventor.mit.edu/

then you are using Version 2.