MIT app inventor - Buttons, Text to Speech, Web and Translate

We just ran this as a workshop at the association of Women in Science conference, so we though we would put it up as an online tutorial too. This will take you through the basics of writing and MIT app inventor App, downloading and installing it to your phone and then following through a few extension challenges beyond those from the standard App inventor tutorials (with a healthy dose of elvish impishness!).

Head over to http://ai2.appinventor.mit.edu/ and login with your google account (or register for one for free) then take a look at the MIT App inventor basics tutorials here: http://goo.gl/sVZMzK.

It's worth noting that you DON'T need an Android phone to test these out as if you have installation privelages to the computers you're working on then you can simply install an emulator. Unfortunately this is only currently an option for OSX and Windows, which also allow direct connecting of an Android phone to a computer with the MIT App inventor editor on by Wifi or USB cable. This awesome little feature instantly clones the app you're creating to your device allowing you to test it in real time. If you're a dedicated linux user like us though, then a nice workaround is to simply use the 'Build' functionality at the top of the page to build your program and then automatically download and install it to your phone using a QR code (however you can end up with a lot of apps installed to your phone this way!).

Our first app: Text to Speech

Aim: An app that speaks some text that the use inputs
        Instructions: Here
Challenge: Extend your app so that it screams when you shake it (check out the .shaking method in the accelerometer sensor)

Our second app: Ball bounce

Aim: An app that allows you to control an on-screen ball
        Instructions: Here
Challenge: Increase the numbers of balls to 5, and allow collisions between balls

Repeater

Aim: An app that recognises voice commands and reads them back to you.

        Instructions: 

Start a new project and set up a basic screen with a button, a label, a speech recognizer and a text-to speech-element. Using the blocks editor, set up these blocks:

Simply, when the button is pushed, the app will try and recognise what has been spoken and will print a copy to the label and then attempt to speak it outloud. Yes, the SpeechRecognizer isn't great at NZ accents. Yes it's a source of much hilarity. Convieniently MIT app inventor have just introduced some new translation functionality in the form of the YandexTranslate design element (found under the 'Media' tab). You can pass this a string of words and it will attempt to translate it into a language of your choice.

Challenge: The 'repeater' app reads back to you in Italian

If you're looking for other languages:

• en - English
• es - Spanish
• de - German
• no - Norwegian
• fr - French
• ru - Russian (however the altered character set will appear in the translation label but not be read out by the text to speech element)

Insulter

Aim: An app that scrapes data from a website and prints it on screen

        Instructions: 

As per usual we're going to start off with a button and a label field, but because we also need data from the internet we will also need the 'Web' element from the Connectivity tab. The set up some blocks:

The first block connects the button with retrieving the html of the website. The second block triggers when that call is complete - and contains and 'if' statement that tests is the website retrieval was successful (responseCode = 200) or not. If it was successful then the returned html is printed to the screen and then spoken by a text to speech element. Initializing the local variable isn't necessary here - but becomes useful in the next step. And yes, you're reading this code right - this will just print the entire html of the website.

So our next step is to 'parse' the website html to allow us to pull out the elements we want. To see the html I'm talking about, head over to http://insult.dream40.org/, right click and select View Page Source. If you look though it you will quickly find two lists of words that the website picks from to get its insults.We can use a 'split' block from the text tab to help us sort through it. I suggest starting by getting your program to grab one insult from the website and display it - then modify that to allow it to grab multiple elements and choose randomly between them. There IS an inbuilt Html Parser method in the Web element, but we were unable to get it working so we just did it by hand!

Challenge: Gets insults from http://insult.dream40.org/ and speaks them.

If you're interested in doing more you can follow our MIT app inventor bluetooth tutorial here: http://goo.gl/QbQhLk

References:

We've borrowed lots of this material from the MIT app inventor team of course! you can find all their wonderful tutorials here: http://appinventor.mit.edu/explore/ai2/tutorials.html and they're by FAR the best way to learn all about App inventor.
We also found this tutorial about getting Yahoo Stock prices really helpful: http://beta.appinventor.mit.edu/learn/tutorials/stockquotes/stockquotes.html
For those that want access to more Android functionality - we suggest Android studio rather than the old Eclipse plugin.