hpr-knowledge-base/hpr_transcripts/hpr2191.txt

Episode: 2191
Title: HPR2191: Building a Soundboard Android App with App Inventor
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr2191/hpr2191.mp3
Transcribed: 2025-10-18 15:30:24

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This is HPR episode 2191 entitled, Building a Soundboard Android App with App Inventor.
It is hosted by Groups and is about 10 minutes long and carrying a clean flag.
The summary is, Groups walks us through how to build Android Apps with App Inventor and Lock Based Language.
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Welcome to HPR, this is Groups.
Today we're going to be using App Inventor to make Android Apps.
I have a Kindle Fire and my Samsung phone and they're both running Android and we're
going to make some apps for them.
Now since this is HPR we're going to do something with noise and we're going to make a soundboard.
And a soundboard is just simply some buttons that you can press to play noises.
And since I'm classy I'm going to use fart noises.
Also my children love this and I help them to build an app like this recently with a
picture of my really good friend and when you press the picture of my really good friend
it plays awesome fart noises.
This is a really cool app and App Inventor I used a lot in my junior high classes so that
we can build cool things really easily, really quickly with kind of the basics of programming
but it's graphical, it's web based and it kind of makes it easy to have ideas and then
make something with them.
So we've got App Inventor pulled up, or AppInventor.mit.edu and on my phone I have MIT AI2 companion
installed which allows me to install the apps on my Android device or you could just
have a QR reader and do it that way or you can download the APK and install it.
There's lots of ways to do it but the MIT AI2 companion is really easy.
So go ahead and install that on your phone and go to AppInventor create an account and
let's get started.
I have some pictures on the HPR website, there's some screenshots of the soundboard so that
you can kind of walk through it with us.
Now when you open up AppInventor and you create a new app, I'm calling mine, HPR Soundboard,
it shows kind of a mock up of the Android screen that shows your palette over to the
left with buttons and check boxes and date pickers and images and things you can throw
in there.
When you drag, for example, button into your viewer, it will show up under Components
so you can select it and there's properties overhead over on the right.
So the first thing that we're going to do, we open this thing up, is we're going to create
two buttons.
You can have as many buttons as you want, you can lay out this thing however you want.
We're going to make it kind of simple.
So I'm going to drag a button over and it will put a button on the viewer that says
Text for button 1, button doesn't do anything, I'm going to drag another button over and
do the same, you know, look the same.
Next, I'm going to change the height in the width and I'm going to change them both to
fill parent because I'm a lazy designer and that will fill the screen.
Now it won't fill it by height but it will totally fill it by width.
You have to add some more of the layout tools if you want to change it to fill by height.
I go ahead and change that and then you can change, this is all in the properties section.
You can change the text and I've changed the first one to fart, the first button to fart
and the second button to just other noise.
Now I need to add some sounds.
There's a media section where you can click upload files but we're not going to get to
that first.
We're going to go into the palette and go down to media where there's camcorder options
or camera options or image picker.
We're going to pick sound and I'm going to drag two sounds into the viewer and they will
not show up on the viewer but they will show up below it where it says non visible components.
Now I have to add two sounds because I'm playing two different sounds and this is simply
a variable that's going to or an object that's going to hold information about your sound.
So I'm going to drag both the sounds in and then we are going to and the properties for
the sound once it's selected.
You can select it in the viewer.
You can select it on components.
I'm going to click on source and upload file and I have a large collection of fart and
B3s apparently and so I'm going to click upload file.
I'm going to navigate to my fart sound and hit OK.
Now I've gotten one sound uploaded.
I've got my two buttons.
Let's go drag some code.
So in the upper right hand side you'll notice that there's two buttons.
One says designer, one says blocks.
I'm going to go from designer which is the currently selected one to blocks and this
allows me to add my code for what my app is going to do.
So when I click on the, excuse me, when I click on the blocks button, it brings me to
the blocks page.
I'm going to scroll down the blocks section to screen one which is my main screen.
I'm going to select button one and it will pop up some code blocks that I can drag
over for my button.
There's lots of options.
You can have it if it loses focus or if you touch up or if it gets focus or if it clicks.
So I'm going to obviously just check click and I'm going to drag that over and it's a
little block that says when button one dot click do and there's kind of like a mouth
and the mouth holds other code.
So then I'm going to click on sound one and I'm going to drag over two blocks.
One block for call sound one dot stop and one for call sound one dot play.
Now the stop button is not required or the stop block is not required but you're going
to have a lot of noises playing over each other if you press a bunch of buttons at the
same time.
So I like to call that sound to stop.
Now if we were doing this much more, you know, proficiently we would create a procedure
called stop all sounds and we would put all the sounds dot stop into it so that I could
have 10 buttons and then call that procedure when every button is clicked to stop all the
other sounds from playing.
But we're just making a simple little app totally want you to play with this and get
there.
All right.
So I've got my sound to stop I've got my sound to play.
I'm going to click back over to the designer view, take a look at my app.
Now I want to make this thing, you know, uber professional.
So I'm going to click on icon in the property section for screen one and I'm going to choose
an icon to upload and this would be the icon for the app.
So I've I've done that.
I'm ready to test my app and I'm going to click up on build at the very top which provides
a drop down where I can get a QR code for the APK or I can just save the APK to my computer.
I'm going to click provide QR code which will generate a little build the app then it
will generate a QR code and that QR code lets me open up my AI2 companion and or just
any QR code reader and scan it.
And then once it's scanned my phone will say, oh no, what's this?
Once this is trying to install and you have to go and enable to install this one, you
know, package and then hit run and then you have an app and I've got an app that I just
wrote that short amount of time that's on my phone that plays the fart noise and that's
great.
And so that when I'm recording HPR I can totally add in my sounds or what I'm making
my own podcast or if I'm just really amusing my children, I can play these fart noises
and it's just great stuff.
My kids love playing with the soundboard and when you're learning to code you can either
be real old school with it and learn the fundamentals of it and type a bunch of text
in them and but when you're a kid that's not exciting like, ooh I access the database
or ooh I add it to numbers together.
But having something physical like these apps is really fun to do that.
My daughter is really getting into scratch which is very similar to this, it doesn't
make apps, it makes little animation games but it's block based and we can hook our
little bits into it and we've got a little Arduino for the little bits and now we can
interface with stuff we build with our little bits into scratch and it's cool and I can
build these little apps for them and they're having just the best time kind of learning
about computer science and logically thinking through things like I don't know block based
languages I wouldn't use it professionally but it's really easy for kids or for someone
who's learning to code to kind of come into the fold with it.
Anyway so I've got my fart app, I'm going to go play with my fart noises, an advanced
fart app that we made has a timer and so you click it and then 10 seconds later it
farts and so the kids will take my phone and they will go put it behind somebody, click
the button and then talk to them until there's a noise behind them, I guess I have a sound
board, I don't have to make the fart noise by hand and then they have a joke that it's
really easy to make the app when people ask them where they got it and that they wrote
it but the hard part was recording the fart noises.
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