MIT App Inventor – now available with Chinese or Spanish Interface

MIT App Inventor – now available with Chinese or Spanish Interface – More Languages to Come | Explore MIT App Inventor.

Click the link, above, to learn how to select your desired language for the App Inventor interface.

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Separately, Part 1 of my App Inventor Bluetooth tutorial may be published on Friday. Because the tutorial covers a lot, the tutorial will be split into a least two separate blog posts.

I also now have Bluetooth electronic parts to support Bluetooth connection on on my Arduino boards. I intend to use those parts to set up a wireless link between my Android phone and the Arduino – which opens up interesting possibilities such as using the Android phone to remote control an Arduino project.

Arduino is a low cost, simple to program microcontroller board. A microcontroller is a very small computer on a single chip. The Arduino board has a number of input and output pins that can be used to control lights, motors and other devices, and can process incoming electrical signals. For example, the Arduino has an on board Analog to Digital Converter (ADC) that converts input voltages of 0 to 5 volts to a number. I used the ADC feature in a project to measure voltage and current consumed by a particular smart phone, for evaluating the impact that algorithm choice has on battery power consumed and the life of the battery. (An “algorithm” is what we call a set of instructions to perform a certain task. For example, a sorting algorithm is a set of rules to sort values into ascending or descending order.)

With a wireless link between the Arduino and the Android phone, we can have sensors (like temperature, or light intensity) that are measured by the Arduino board, and then send those values to an app running on the Android phone. The phone could then, perhaps, process the external sensor data or collect it and send it on to the Internet.

App Inventor Bluetooth Communication tutorial coming soon

Android phones and tablets support Bluetooth communications (“BT”).

BT is a very low power, very short range communication technology used for connecting earphone and headphone adapters, wireless microphones, and wireless keyboards and mice to computers and tablets.

App Inventor supports BT links and can be used to transmit data back and forth between two Android devices.

When two devices communicate, one device acts as a “server” and the other as a “client”, although either send and receive data.

I now have basic Bluetooth communication working between two Android phones. As I finalize the Bluetooth sample app, I will post a tutorial here on how to set up Bluetooth and how to write apps that use Bluetooth communication.

Longer term, I intend to connect an App Inventor app to an Arduino microcontroller board using the Bluetooth link. I will post information on that once it is available.

(Due to volunteering every evening with a FIRST Robotics team, and a few extra things going on, my updates are a little less frequent at the moment – sorry!)

“100 Best App Inventor Tutorial Videos”

This is a machine generated list of App Inventor tutorial videos. I have no idea which ones are the best (some appear to be out of date, for AI version 1) but you might find these links of use:

Link updated March 24, 2017 – try this one:

100 Best AppInventor Tutorial Videos | Meta-Guide.com.

 

Total MIT App Inventor registered users reaches 2.7 million

The total number of MIT App Inventor registered users has reached 2.7 million.

My guess is the number went up, in part, due to the “Hour of Code” project in December, which provided young students with very brief introductions to many types of programming.

Using the Spinner Control for Selecting Items

When your app needs the user to select an item from a list of choices, use the Spinner control.

Suppose we have a really simple restaurant menu that provides a choice of tacos and drinks. Our customer may select a Chicken, Beef or Vegan taco from an interface that looks like this:

Spinner-Screen

Touching the Chicken Taco item on the screen displays a set of options – select a desired item from the list:

SpinnerScreenshotThe Designer View

Continue reading Using the Spinner Control for Selecting Items

Updated: Writing and Reading Text Files Using App Inventor

This post is a major update to a previous post on reading and writing text files using App Inventor. This revision includes information on how to locate the text files you create in your App Inventor apps, plus how to transfer those files from your smart phone or tablet to your computer.

An earlier blog post described how to store data using TinyDB so that an app’s data can persist between uses of the program, or even to share data between screens in a program.

Another way to save data is to write the data to a file on your Android device. App Inventor has introduced a File control that lets us write text data to a file and then read it back, later. As we will see, the File control is not the easiest thing to use but with some work, the control can be used to store data from our program into a file.

Once data is in a file, you could, hypothetically, transfer the file from an Android to device to another computer. Because Android stores the files in a way that they may not be readily accessible – or even visible – we need to use some simple tricks to find the file and transfer the file to a computer.

Update: To learn more about text files and transferring data in the CSV file format, check out Volume 3 of “App Inventor 2 Databases and Files” – thanks!

Continue reading Updated: Writing and Reading Text Files Using App Inventor

Update: Reading and writing text files with App Inventor

I previously posted a short tutorial on writing to and reading from text files stored on an Android device, using an App Inventor app.

Unfortunately, as some comments noted, the file being created seems to disappear – the data is written and can be read back – but the file is no where to be found on the phone!

After some research, I now know where the file is – and also how to copy the file from the phone (or tablet) to your personal computer.  While the solution to finding and saving the file to your computer is ultimately easy, I need to update the tutorial and explain some things about the Android file system. You will also need to install a free app on your phone in order to copy the file to your computer.

I have posted an updated tutorial that explains the details and shows how to store your files in the right location, how to find them (they are hidden from most views), and how to copy them to your personal computer.

App Inventor Alert: Problems loading projects?

From the MIT App Inventor web site:

Summary: We have been having problems with storing “assets” image, sounds and other objects that you upload to your projects. We are working with Google to resolve these problems as soon as possible.

Things to be aware of:

If we fail to read an asset when you load your project, we substitute a zero-length file. Be careful exporting your projects, as assets may be missing from the “.aia” file exported. Make sure you keep a local copy of your assets on your own computer.

We have been making modifications to the system to mitigate the worst of the problems. In particular we will never serve up a missing asset to the “buildserver” when you package an App. This ensure that if you successfully package an App, the resulting APK is valid. If we fail to read an asset, you will get a “Build Failed” message. If this happens, just keep trying the build. It may work the second or third time around. If it never seems to work, you can remove your assets from your project and upload them again. This may help.

via Problems loading projects?.

The quick and easy way to write Android Apps