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Building your first app with App Inventor

Let's create a real app that can work on your Android device

Remember the Hello Purr video in the first task? How about going through it step by step until you have the app working on your device?

Here it is again so that you can follow along:

Textual tutorials are also available, with instructions on how to use a real device or the emulator:

If you have a phone you can follow this tutorial.

If you want to use the emulator please follow this other tutorial.


To finish the task could you leave a tip for other App Inventor explorers about how you solved any problems you might have encountered?

We would also like to know if you have a preference for the video tutorial or the textual ones so that we can tune in resources in the future. Please leave us a message in the comments!

Task Discussion

  • Tina said:

    Finally found the cat and sound downloads. Not hard and pretty easy to execute. Cant wait to get an android attached

    on Jan. 21, 2013, 11:59 p.m.

    Jos said:

    Hi Tina,

    just in case someone else is wondering, the pic and sound are linked in the tutorial:

    on Jan. 22, 2013, 6:41 a.m. in reply to Tina
  • Tina said:

    where do I find the kitty graphic> I tried to add but it was not in the folder

    on Jan. 21, 2013, 11:02 p.m.
  • Tina said:

    where do I find the kitty graphic> I tried to add but it was not in the folder

    on Jan. 21, 2013, 10:56 p.m.
  • Columbia Area Career Center "G33kyGirls" said:

    I am getting The buildi server is currently busy.  Please try again in a few minutes.  


    How can I fix this?????

    on Jan. 17, 2013, 1:44 p.m.

    Angelica said:

    Hi CACC,

    I have been getting that message a lot too, but I just usually reload a few times (right away) and it will work within a couple of minutes.

    on Jan. 17, 2013, 3:01 p.m. in reply to Columbia Area Career Center "G33kyGirls"

    Columbia Area Career Center "G33kyGirls" said:

    Angela, I have tried it many times and still get the message. Laura
    on Jan. 17, 2013, 3:23 p.m. in reply to Angelica

    Jos said:

    Hi there, 

    the build server seems to be very busy at the moment. I've done a build and it's taken 6 minutes, which is not too usual. If you try again in 10 minutes or so, it should be good to go.

    on Jan. 17, 2013, 3:31 p.m. in reply to Columbia Area Career Center "G33kyGirls"
  • AHMED said:

     ihave done to install the app inventor and java but i dont know how to start aap inventor their is no option of start app inventor in my window 7 help me

    on Jan. 15, 2013, 10:24 a.m.

    Jos said:

    Once you have set up the software in your computer you can visit the site:

    on Jan. 15, 2013, 10:27 a.m. in reply to AHMED
  • AHMED said:

    Hello where is the video i cannot find any video in this page

    on Jan. 14, 2013, 9:25 p.m.

    Jos said:

    Hi there,

    the video is embedded in the task, just under the sentence: 'Here it is again so that you can follow along:'

    Can you not see it? The same video is also available in task 1.

    on Jan. 15, 2013, 5:31 a.m. in reply to AHMED
  • Margaret said:

    I finished; I had some challenges keeping track of which was the correct thing to be looking at -- the emulator, the blocks editor, and the design editor, but it works fine.

    I used the written directions; next time, I'll try the video.

    on Dec. 5, 2012, 11:25 p.m.
  • jsfllc said:

    Went off without a hitch. I used the emulator and learned to be patient as the emulator takes a long time to load. btw. I perfer videos, thanks.

    on Nov. 20, 2012, 8:39 p.m.
  • Kodjaman said:

    Hooah! finished first app.

    on Sept. 3, 2012, 8:31 a.m.
  • Teguh said:

    Why the size of packed apk is very big? 1.48MB, is that normal?

    I saw much complicated app could achieve smaller size, no bigger than 1MB. How come? Will the size going much bigger for more complicated app?

    on Aug. 13, 2012, 9:09 a.m.

    Jos said:

    Hi there,

    you are right. App Inventor packages extra libraries for most of the components available, even if you don't use them. This is a kown issue that the App Inventor team is working on, but for now, that is how it works.




    on Aug. 13, 2012, 9:30 a.m. in reply to Teguh

    Teguh said:

    Ok, i wish it solved before i mastered this android app dev :))

    Btw, i successfully followed the first version of tutorial which using android cell phone, the cat miauw perfectly. But i fail with the emulator version. Somehow the emulator always failed to connect.

    First it loaded like a phone without simcard, so sluggish (is it normal?), but never scan its SD Card, also the app inventor could not detect it. So i closed it and reload, then it stays black forever.

    I wonder what is the minimal hardware requirement to play the emulator, it looks good but so sluggish, how fast the CPU it required to play smoothly?

    Btw, i still on HP mini netbook :)

    on Aug. 13, 2012, 9:42 a.m. in reply to Jos

    Jos said:

    Hi there, to be honest I don't know what the minimal requirements are. Please have a look at the troubleshooting guide to see if you find any answers... and let us know if you do! :)

    on Aug. 13, 2012, 10:41 a.m. in reply to Teguh
  • thierryf said:

    and same

    used both  vid and text 


    i thought i had it from the vid but alas the text got me this far

    needed both

    on Aug. 12, 2012, 7:15 p.m.

    Jos said:

    Thanks for letting us know!

    on Aug. 13, 2012, 9:31 a.m. in reply to thierryf
  • thierryf said:

    hello all 

    No probs here 

    fantastic  once i followed instructions exactly . 

    thanks this is a blast ~!!

    on Aug. 12, 2012, 7:13 p.m.
  • Anonym said:

    I'm using Linux Mint (Ubuntu based dist.) and, when I was trying to open the Blocks Editor, the browser asked to me where to find the AppInventor command...

    Finally I discovered I had to install a deb package for the AppInventor in Linux, here is the package:

    Best regards,


    on Aug. 8, 2012, 3:50 p.m.
  • Kapil Chawla said:

    Major problem I had was that I could not install Java 7 because windows had prevous currupted installation of Java 6.

    Windows also did not allow me uninstall Java 6. 

    I removed it using MicrosoftvFixitvProgram Install Uninstall utility.



    on July 27, 2012, 11:42 a.m.

    Jos said:

    Thanks for the pointer!

    on July 27, 2012, 11:44 a.m. in reply to Kapil Chawla
  • Kallisti said:

    I appear to be entirely unable to open the Blocks editor; I've downloaded the file 'AppInventorForAndroidCodeblocks.JNLP' and opened it, or tried to. When I double-clicked on the file, it brought up the Java logo briefly, then changed to a window titled 'Starting application...', which has been sitting there unchanged for twenty-seven minutes. Attempting to open the Blocks editor prompts me to download another copy of the file.

    Actually downloading a new copy of the file accomplished nothing; half an hour into the second attempt, the website promted me to ask if I wanted to continue waiting for the blocks editor to open.

    on June 21, 2012, 5:47 p.m.

    Jos said:

    Hi there,

    any chance you are using Java7? Also would be helpful to know what operating system are you working on. The Java logo that pops up at first should tell you which version it is (probably 6 or 7). There are some problems with 7 at the moment, so if you could install Java 6 instead, that should fix the problem. Let us know how it goes!

    on June 22, 2012, 5:09 a.m. in reply to Kallisti

    Kallisti said:

    I am indeed using Java 7. That's the source of the trouble, then? I'll fix that sometime tomorrow.

    on June 22, 2012, 5:23 a.m. in reply to Jos

    Jos said:

    Most likely it is. Don't know exactly what the cause is, but will look into it. Let us know if downgrading to Java 6 works for you.

    on June 22, 2012, 5:33 a.m. in reply to Kallisti

    Kallisti said:

    Downgrading has resolved the trouble; thank you very much.

    on June 22, 2012, 6:48 p.m. in reply to Jos

    Jos said:

    Excellent! Happy inventing!

    on June 22, 2012, 7:03 p.m. in reply to Kallisti
  • franciscoteca said:

    Hi there!

    I did the task, and I liked the combination of video and text tutorials.

    I have one doubt. When I installed the .apk file of the app on the phone, it ask me for permissions as access to internet and some else.

    Is there any way to select the permissions an app has?

    I think that, for example, is not necessary to give so many permissions to the Hellow Purr app.



    on June 16, 2012, 8:36 a.m.

    Jos said:

    Hey Fran,

    as far as I know the permissions are the same for all apps, so anything that you can do with App Inventor has to be made available. You are right in thinking that no internet permissions should be needed for certain apps, but it's one of the trade offs that has to be made when developing this kind of software.



    on June 16, 2012, 1:55 p.m. in reply to franciscoteca
  • Ernesto Gálvez said:

    I like the tutorial text. it was fun to do this first Android application!!!

    on June 5, 2012, 10:55 p.m.

    Jos said:

    Thanks for the info. There is more links to tutorials and snippets in the last task.


    on June 6, 2012, 5:10 a.m. in reply to Ernesto Gálvez
  • pdonaghy said:

    Liked the video which is very clear but  still used the text tutorial to build the first app.

    on June 3, 2012, 4:18 p.m.

    Jos said:

    Hi there, thanks for your comment. I feel the same way, it's great to have a clear introduction to the task like in the video, but the text tutorial is easier to follow. Hope you are enjoying the challenge!

    on June 3, 2012, 5:06 p.m. in reply to pdonaghy