AI2 Inventor Forum News: 12/30/14

2014년 12월 30일 화요일

Blocos (blocks)

Hello!
I'd like to know how to copy blocks to not have to create them again in the same screen. In Scratch you can copy them.

before copying blocks, you should read and understand this: Building apps with many screens

and then if you really think, you have to copy blocks, you can use this method:

How to copy screens by

Scott and a video by

Hossein

Advice: Before posting, it's a good idea to search in this forum. Many others have likely run into problems similar to yours. How to search see screenshot.

Multiple Screen Problem...

I have created 1 android app the basic structure of app is...

Screen1: Contains 17 buttons..

Now the problem is, i need screen for each 17 buttons which also contains the buttons. but there are different number of buttons each screen contain.

I have created 17 screen for listing the button(That is too many)..should there are any way to reduce the screen size using tinydb or tinywebdb.

After reducing the size of screen can my app perform much faster compare to multiple screen app.

You should NOT use more than 10 screens... Please read the section on screens in my tips below:

For our App Inventor Tips, visit TwoDogApps.com by clicking here!

Notifying the downloaders phone

Hello, I'm working on an app the requires constant changes, I wanted to know how can I set the app to send notifications to a downloaders phone informing them about new changes that happened in the app. Thank You.

Presently, push notifications are not available in AppInventor. If you put your app on Google Play, and they download it from there, whenever you update the Google Play file they'll get the update too.

An internal error has occured

I have my project almost finished. When I try to add a new element like a label or a button, I get the error "An internal error has occurred. Report a bug? ". I also have this error:

otes = Browser: Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36

foundIn = nb139f

faultData = com.google.gwt.core.client.JavaScriptException: (TypeError) : Cannot read property 'A' of undefined

projectId = 5135668264042496

I have to add that after this happens, the label or the button appears but its set of blocks doesn't.

I can build the project, can run the emulator and the app works fine. I don't have any warnings or errors and I've already changes browsers and restarted my computer.

Any suggestions??

What happens when you back up a step and load one of the previous AIA files you made?

If I load a previous version I don't have the error.

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So that tells you something you added is causing a problem. Can you add things back tot he older version to bring it up to the current version? Make an AIA file after each successful add, and you'll know exactly where you're failing...

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Ok Enis, thank you very much for your help!

Ditto Carlos! Read my tips... you might be getting towards the size limit and that's why you're having problems... that's just a guess.

this looks like a App Inventor bug. Unfortunately, it's one that might be hard to find. Could you send us the AIA file together with a description of what needs to be done for elicit the error.
It might take a while for us to look at this, but we'll try.

How do I align a TextBox with a Button?

For example, I'm trying to create a game scoring app and I've used HorizontalArrangements in every row and put the respective textboxes and buttons where they should belong. However, for some reason the text boxes don't align with the buttons properly. I've tried everything from adjusting the heights of both items but they still refuse to align (I think it is the buttons fault because after I replaced it with a label, everything was aligned like it should be). Also, I was wondering if there was any way to get rid of the cursor and yellow outline around the last textbox after anything is inputted inside of it. There doesn't seem to be an option for this so I was just wondering if there was a answer. I have attached a picture of the problems. Thank you for your time, I appreciate it!

On the last one, no... that's the focus box and it's part of the Android operating system... wherver your cursor is, is where the focus box will be.

On the first one, the alignment... it looks to me that the top of text of the components are all aligned. Have you tried a table arrangement?

Thanks for the response Enis. You're right, the text is aligned. Do you know what could be causing this though? I'll use the table arrangement as a last resort (it gets messy once there are a lot items in it).

Companion Connection Error:

Hello, I just cannot get the companion (ver 2.23) to run on my phone. (moto g android 4.4.4) Keep getting connection error. have read everything I can find.

The pc and phone are on the same wi-fi network.

I can ping the phone from the pc and can access rendezvous from pc and phone.

Update: I have my companion working. The fix was updating Java and uninstalling 2 outdated versions.

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Glad you got it resolved...

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Image select in site dont work.

Hello, today i make my first app to connect my site. All works fine, but when i click on button in my site to select one image for post, nothing happens, the dialog box to choose a image don't appears.

When i use my Desktop browser it's work fine..

the webviewer is no full browser, therefore this will not work

you can try to use the activity starter instead

Cannot connect Samsung tab to windows 7 laptop

I have Samsung Tablet model# GT-P6210, Android4.0.4 and windows 7 laptop. I tried with both firefox and chrome browsers on my laptop. Same error. I tried both Wifi and USB connection modes, neither works.

I pretty much tried everything I could possibly try. I spent whole day on this. Please help me more forward. Here are the steps I tried.

0. I launch the MIT App Inventor 2 app and scan the code and click it to "connect with code" button. It says "Failed to Connect to the MIT AI2 Companion, try again." in the browser in laptop. It does not say anything on the tablet app for long time. If I press the button again , throws 1103 error.

1. I did setup WIFI hotspot from my laptop and made tablet connect to that. I could ping and also telnet to 8001 port. I could not telnet to port 9987.

2. USB dirver seems to be up to date. Windows keeps saying it is best available driver. I also downloaded USB driver zip file from the below android developer site and tried to install these, but windows device manager keep saying there is no valid driver file in this. I unzipped this zip file and selected 64bit and 32bit both the files, but none seem to match. Please do let me know if I need to get developer USB drivers from a particular website and file names etc details.

http://developer.android.com/sdk/win-usb.html

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Did you load MIT Companion from Google Play on your Samsung? You need it for both WIFI and USB development.

Regarding the USB drivers, try Samsung: http://www.android.gs/download-samsung-usb-drivers-for-android/

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Yes, I did download MIT Companion on tablet. I tried both version one and version two companions. I tried version 2 for the most part, just tried version one just to check if it works... but it didn't work either. I will try Samsung USB driver and let you know how it goes.

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I just installed Samsung USB driver and updated the USB driver in device manager in laptop. Still the same issue.

I forgot to mention, yesterday I also installed "Samsung Kies". It installed several drivers etc. It took lot of time to install on laptop. I am thinking this Samsung USB drivers were tested yesterday also. I am just wondering if anyone else is able to connect Samsung tablet to Windows7.

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I have a GTP3113 Samsung tablet...it works fine with Windows. I wonder what is not working for you. WIFI works immediately without installing anything other than Companion on your Tablet. Did you follow ALL the instructions here: Setting Up App Inventor ?

In WIFI, are you connecting to the same WIFI as on your PC.... stated another way, the PC and Android need to be connected to the same network ...could you possibly have the Android on a 'guest' router position?

Also, here are are lot of things that could cause connection errors. 9. 12. or 13 could be YOUR issue. Also, do you have a Project loaded in the AI2 browser?

One of the following possibly applies to your code (all may not apply to your code):

1) You have coding errors in your blocks. In the Blocks editor, look in the lower

left corner of the window for the yellow and red triangle icons. If the red icon has a value larger than 0,

you have a serious coding error. Find the block in your code that has a red triangle and

fix it. Red triangles always inhibit creating an apk or running a project in the

emulator or possibly creating an aia file. Yellow triangles are more forgiving,

however, sometimes, these need to be fixed because they trip an internal warning and not billing puzzle piece sockets are left un-filled.

2) Your source file (the aia file) is larger than the 5Mb limit allowed in AI2 (the aia can not be larger than 5Mb). You may have put images or other resources in your Media (resources) that you do not use in the app.

All the images and sounds in resources count toward the 5Mb limit along with the source code. You can program

apps larger than 5Mb in the browser, but the apps will not compile and might not run in the

emulator or the project may not save as an aia. If this is the case you need to reduce

the size of your image and/or sound files. Most image files can be made quite small

by resizing them using a photo manipulation program on your PC to less than 50Kb each.

3) You might have more than 10 Screens in your app. AI2 becomes unstable when more

than ten screens are used. Projects CAN be built with slightly more screen but then you should expect your app to occasionally behave erratically.

4) You might have set a Screen icon in the Designer Properties for your project that is too large. Use an image

sizeof 48x48 px or 96x96px instead and only use jpg or png images. *.ico files are not

supported. The 'icon' (actually an image) can be as large as 520x520 (I think that is the size GooglePlay apps require). The smaller 'icons' work fine otherwise.

5) You did not code the entire project using App Inventor 2. If you used one of the

third-party AI2 clones,you might not be able to load a Project into the AI2 compiler or

create an apk with the standard AI2.

6) If you incorrectly modified the project's Manifest files using a third-party tool, you may have issues.

7) Sometimes, if you have LOTS of Layouts on a single screen, the apk might not

compile. How many is a lot? I do not know, keep adding layouts and buttons, compile and try again...when the server crashes, you got a lot.

8) The network you are using may be overloaded (possibly a school network), or you have other applications running in the background on your computer, or your virus checker is doing a scan. Sometimes, just trying to access the MIT server a few minutes later will give you a more favorable response.

9) If you have BlueStacks on your home PC (BlueStacks is a special emulator that allows Android apps to run on a PC). The Google emulator on AI2 cannot run unless BlueStacks is disabled and all of the BlueStacks processes are shut down. On a Windows PC, you use the Task Manager to 'kill' running processes.

10) Are you using Sensor controls (except for the clock)? Most Sensor controls or controls related to sms or the phone do not work in the emulators. They need to be tested on a device.

11) If this is an issue about the Project loading slowly on your device or on the emulator: Be aware, the more images, layouts, components you have on a screen, the longer it takes for the emulator and Companion to render the graphical screen. How fast the emulator renders is partially a function of your hardware...how much ram you have, your cpu clock speed etc. Sometimes, with lots of graphics, the emulator will just give up. Can you develop live using WIFI or using USB? These options almost always render faster than the emulator but will not be at lightning speed if you have lots of graphics. Be patient.

12) This happens too: We have seen instances where it is probable the Google Cloud messed up; other instances where an older PC has had memory issues and caused file corruption of the Project and instances where a user is using a very slow Internet connection (like dial-up) and it is just too slow.

13) Do you have an AVG, Eset or AVAST virus checker. Some versions of these products have been reported inhibit running the emulator unless (in the case of AVG) the Advanced Link settings on the software are set to allow AI2 communication.

I am almost about to give up on MIT appinventor app. Thanks for your response. Can we talk? You could call me at 650-353-1183. Or let me know a phone number to reach you.

Yes, both tablet and laptop are in the same WiFi. I installed "MypublicWifi" application yesterday on my laptop and made sure both tablet and PC can connect. I am able to ping tablet ip address from laptop. I can also telnet to 8001 port on tablet. I can NOT telnet to 9987 port though. I am not sure if that is a problem or not.

I just have one simple app. That is simple radio. My app just has one button, "play", that is it.

Try this simple app. Your radio app might be the problem. Create a new Project. Place a button on the Designer screen. Do nothing else. Now,

Connect > AI Companion or Connect > AI Emulator and what you should see is a screen with a button that has as text "Text for Button1"

This could be your problem: "Yes, both tablet and laptop are in the same WiFi. I installed "MypublicWifi" application yesterday on my laptop and made sure both tablet and PC can connect. I am able to ping tablet ip address from laptop. I can also telnet to 8001 port on tablet. I can NOT telnet to 9987 port though. I am not sure if that is a problem or not. " You should NOT have to telnet to 8001 and why you would want to telnet to 9987 I have no idea.

Setting up AI2 to use with WIFI is very simple, provided you do not have unusual hardware or Internet connections.

MypublicWifi might be your issue.

My home wifi is very simple and default setting with password protected. My laptop and tablet could connect without any issues to home wifi. I tried to ping and telnet to phone as per the instructions given in appinventor site link below.

http://appinventor.mit.edu/explore/support/explain-wifi-connection.html

Since I could not ping phone from laptop when using my home wifi, I hosted a hotspot on my laptop itself to made my tablet also connect to that.

Get size of image

In order to send a file to godaddy with POST, I need to include the Content-Length header, so I need to find the size of the file that it is sending (using a picture). Is it possible to get the properties of a picture and find its size in it?

unfortunately not possible

but there are other web hoster which are not as restrictive, see also https://puravidaapps.com/postfile.php

Lookup in Pairs . csv file (I need a tip)

I need a tip.

I make a "lookup in pairs" program that works, the thing is that I need create many "pairs" that i have in an excel sheet.

Is possible, using a csv file, to create the list pairs automatically?

Example

I have this table in an excel (I have approx 400 rows)

N° Name

456 John

986 Peter

435 Sofia

How can I make this by creating the list from a csv file, without having to make it one by one?.

This is not working but I've been trying in several ways and I just can't figure out how.

yes, just use the list from csv table block to convert the csv file into a list of lists

try this but is wrong...

well, this is completely wrong

in your File.GotText event you have to put the following block

set global name to list from csv table get text

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Hi Taifun Thanks alot for your advices, I appreciate that.

I did this but I get this error

csv means comma separated value and not semicolon separated value

use comma as delimiter in your file and try again

Thanks a lot for your help.

I create a cvs with comma separated but iit don't work.

I will continue trying and will give you feedback.

It would really help if you provided a screenshot of your relevant blocks, so we can see what you are trying to do, and where the problem may be.

This is it:

create the list from a cvs file and not one by one.

attached is my cvs file format and structure.

I can share the aia file if it's needed.

db2.csv

did you try this?

in your File.GotText event you have to put the following block
set global name to list from csv table get text

how does your File.GotText event now look like?

Yes I did it but I get the errors posted before.
The comma error and the errror list format.

You might want to provide a screenshot of your error message then?
Also it helps to use Do it to debug your blocks...

gabriel.aia

Thanks Taifun you are AWESOME!!!

I been trying to solve it but it was hard for me. I'm learning and this was a great learning experience.

Now I will start working in others features! Thanks

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Copy screens

I'm writting here to solve a problem with app inventor. I have an app with one screen full of blocks and I need the same screen (the style and the blocks) but only changing 2 o 3 values. Then I dont want to rewrite all agaiiiiiiiiiiiiinn! I'm looking for how copy a screen on the Internet and I found out a video of a boy doing it (Hossein) but it doesnt work.

Somebody knows how to do it? If it's not possible, PLEASE APP INVENTOR try to include this options PLEASE! I think it's important for creating apps quickly.

you should avoid redundancy, to copy blocks to another screen which does almost the same is considered bad programming style

please read the following document to find out, how to avoid this

Building apps with many screens

It depends of the app you want to create. See my example:

I have an iron piece and in the app you can change the dimensions and the force to which it's subjected. If the force is >x the pice has ones conditions and if the force is <x has anothers. Then, i need 2 screens with these differents conditions and the mathematics equations are really similars...

Even so, although I need to improve my knowlege about programming (im a civil engineer), the solution is not say: DONT DO THAT. I wanna do it and i wanna learn how to do it, not like you that give me this solution;)

As Taifun said, you want to avoid redundancy. For example... You do NOT need two screens in App Inventor to do what you want to do. You could have both situations in two separate arrangments, one visible and the other, invisible. Let's say the arrangement that's visible is the iron piece with >x applied, and you want to show the <x applied, you simply make the > arrangement invisible and the < arrangement visible.

Don't try to overbuild... as a civil engineer, you know exactly what that means...

Okey, I accept your phylosophy and I practise it: "If you dont know how to do something, look for others ways". But it's important discover how to do things that you dont know, in order to increase your mental capacity. If Einsten had thought like you, never we heard about the gravity. Dont talk like a goods progammers if you arent, and if someone write a post in the forums, dont try to put him down. Keep calm please!:)

If perhaps you REALLY need that many screens, Screen1 is always the first screen, but you can rearrange them or copy information from one screen to another using this method:

How to copy screens by Scott and a video by Hossein . (you have seen the video, the advice is easier to understand; try it).

You are correct Trufa, sometimes additional screens are a very good solution. You have to figure out how YOU want to design your app. Frequently reusing objects on a single screen works well, however designing on a single screen, in many ways is more complicated. Designing on a single screen avoids passing variables, multiple copies of TinyDB etc. But if you do not need those, the use more screens; be aware 10 Screens is the practical limit with AI2. Use more than 10 and AI2 starts to become unstable.

Please keep in mind that you have two basic limitations in App Inventor... no more than 10 screens, and your AIA file cannot exceed 5MB unless you're using a personal local server.

Nobody here is trying to "put you down," and we're all VERY good programmers. What we're doing is giving you sound advice.

Thank you SteveJG!:)

This is the veido i've said that I've watched. I'll do the same and App Inventor reports me a bug:( I dont know what is the problem. Thi evening I pass this video to a

informatic friend and later i'm going to write his opinion here (if it's correct and if not the solution if he finds it).

Thanks!^^

Thanks for the advises! (but i've never had more than 3/4 screens xD).

SOMEONE HELP ASAP!?

I take computer science as a GCSE at school, and I am making the first three screens of my app on app inventor 2. Two of the screens require a list, one is the challenge a friend function, it requires me to provide a list of contacts of the user, so that the user can select one and send a default text to them to let them know they have been challenged to complete a puzzle. I don't need to know any of the blocks or coding for this, I just literally need to know how to use ListPicker, Listview, and the Contact picker, please help.

Here are the doc pages for what you're looking for:

Listpicker:
http://ai2.appinventor.mit.edu/reference/components/userinterface.html#ListPicker

ListView:
http://ai2.appinventor.mit.edu/reference/components/userinterface.html#ListView

Contact Picker:
http://ai2.appinventor.mit.edu/reference/components/social.html#ContactPicker

For the first two... You set the elements of the list picker in Before.Picking, and the action for what you want to do in AfterPicking. If the ListPicker is NOT visible, the button won't show and you have to display the list programatically. If it's set to visible (showing), a button will show on your design and runtime screen, which, when clicked, will show the ListPicker.

How to Query a Fusion Table?

We are having success with AppInventor but we are now stuck. We built the pizza app and are able to populate a fusion table. In a separate app we are able to view the data in the table. What I am asking students to do next is to query that database and return the result to the tablet.

A simple query is what I want them accomplish. For example:

If pizza = 'pepperoni' than return that row.

Data (Pizza Type) is to be selected from a list, which we can view, the query submitted - via a button - to the table and the values returned to the screen.

Problem is we do not know where to start. I have researched the forums, asked the Internet, etc. and am stumped/confused. Just need a place to the students to begin.

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you need a SELECT query

SELECT * FROM <tableid> WHERE Pizza = <Listpicker.Selection>

How to INSERT, DELETE and SELECT a Fusiontable by Viktor

Here are the docs for the Fusion Table control...http://ai2.appinventor.mit.edu/reference/components/storage.html#FusionTablesControl

You will have to use the GetRowsWithConditions block to query the table and extract specific rows that match the conditions...

We are having success with AppInventor but we are now stuck. We built the pizza app and are able to populate

Student getting "YAIL compiler - DX execution failed."

A student of mine said she had her app working using AI Companion, but then a connection error occurred and would not reconnect, despite trying on different computers and different tablets. When attempting to build the app, it stops at 95% complete during the Building APK phase and gives this error:

App Inventor is unable to compile this project.
The compiler error output was
________Preparing application icon
________Creating animation xml
________Determining permissions
________Generating manifest file
________Attaching native libraries
________Copying native libraries
________Attaching component assets
________Compiling source files
(compiling appinventor/ai_stephcougar2021/Battleshipworks/Screen1.yail to appinventor.ai_stephcougar2021.Battleshipworks.Screen1)
Kawa compile time: 10.597 seconds
________Invoking DX
YAIL compiler - DX execution failed.

Any ideas on how to solve this?

Below are some general guidelines to following regarding apk compile issues, emulator issues ..generally, they are all related.

I suspect the student made some changes to the project just before compiling. The most probable causes are #s 1, 2, 3, and 4. This could be something else too. You may be aware of the Google Cloud issues some users are experiencing (see the red warning on the AI2 Start screen). I do not think the Cloud Issue is the problem so consider the following: