Preparing Your Android Device

To use our tablets in this class we need to do the following:

  1. We need to be able to take screenshots of the tablet screen to submit for our assignments. So we need to turn on the screenshot feature.
  2. We need to install a QR code scanner on our tablet so we can read QR codes.
  3. We need to install a special app called AI2 Companion.
  4. Enable unknown sources option on your tablet.

Here are the directions for doing each of these things:

Part 1: Turning on the Screenshot Feature on Asus Tablets

The Asus tablets come shipped from the factory with their Screenshot feature disabled. We will need to turn on this feature so that we can periodically take screenshots and paste them into our interactive website as part of submitting our work for the teacher to grade.
This video describes what needs to be done to turn on this feature.

Part 2: Loading a QR Code Scanner

Periodically, we will need to read QR codes (these are the black-and-white square diagrams that look like bar code labels you often see displayed in stores) on our tablets. These QR codes provide a quick way for us to download new apps into our tablet for later use. When shipped from the factory, your tablet does not contain a bar code/QR code scanner. So we will need to download and install one. Frankly, any one will do. If you have one you already use, feel free to download it and use it. Otherwise, here are directions to download and install a free one we recommend called ZXING:

  1. Turn on your tablet
  2. Go to the app store
  3. Search for QR code scanners
  4. Locate the one from ZXING
  5. Download and install it

Parts 3 & 4: Loading AI Companion App & Enable Unknown Sources

While working on building applications for our Android devices, it is helpful if we can periodically download what we have created so far and test it out even before we have finished building the entire app. The programming language we will be using to build our apps is called MIT App Inventor 2 (AI2). There is an app called AI Companion that can sit on your Android device and work with AI2.
We need to download AI Companion on our Android devices to work with AI2. We need to do this only once, at the beginning of the year.
The following video explains everything we need to do on our Android device to get it ready to work with AI2, including how to download and install the AI Companion app. Here is the link mentioned in the video.

Known Bugs in App Inventor 2

  • When you load an app into your device using the App Inventor 2 Companion, sometimes the images do not load on the first try.
  • Sometimes sounds do not play the first time the PLAY is called. To get around this, in your Screen.Initialize block, put all the sound files in a list. Then one at a time set the Sound.Source to each item in the list. Loading the sound files like this appears to solve this problem.
  • Certain actions cannot be done in the global initialization section of the code. For example, you cannot initialize variable x to the value of variable y. This is not really a bug. The problem is that AI2 has no way to guarantee the order of when objects and variables get initialized. Your instructor will explain this limitation in detail during one of the class lessons towards the middle of the course.