AI2 Inventor Forum News: 12/29/16

2016년 12월 29일 목요일

Extra option

Scroll able option is not available while we are working in design . PLEASE WORK ON THAT ???????

Maybe you could ask a bit more politely.

Anyway, you can work around this problem by making items at the top of your screen temporarily invisible.

what about setting the scrollable property of the screen to true?

I really like the concept of the app inventor, but I made a mistake on the designer, and now I can't delete anything. Old projects can't be ridden, the mistake will remain there forever. Anyone had the same thing happen to them, and if so, do you know the solution?

The post here should help you understand why you cannot delete components: https://groups.google.com/forum/#!category-topic/mitappinventortest/k48uyPMyaRw The post explains what you probably did. You need to reset the Chrome settings so it can allow the Chrome browser to delete components while using App Inventor ..the post explains how.

Simplified: the cure, with Chrome is to type chrome://settings/ in the browser's URL box and get this screen and press reset settings.

It does not look like you have used the forums yet, as a search using the search box above would have returned several threads about this topic.

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.

See also the Top 5 Tips: How to learn App Inventor

Push Up Notifications (Help/Ayuda)

Good to all, I wanted to know if they can help me to send notifications from the computer, and to reach all those who have my App in the form of Push up (As with whatsapp chats or emails,)

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Buenas a todos, quería saber si pueden ayudarme a mandar notificaciones desde el ordenador, y que lleguen a todos los que tengan mi App en forma de Push up (Como con los chats de whatsapp o los emailes,)

This is not possible, for two reasons: An AI2 app cannot run in the background and second, how would you know who has installed your app? Are you requiring some kind of registration?

My english is very bad, sorry about that.

Look, I wanted this, but only works in 'local', I need to do the same, but sending the notifications from my PC to all persons who have my app, this is only a test,

At the moment, only my and my boss have the app.

ScreenRecord_2016-04-27-12-52-44.mp4

One solution might be to store a message in a shared text file on the web which also contains a date stamp.

Upon startup, the user app will check the contents of that file and compare it to the last date stamp stored on the user device.

If they match, then the message has already been read by the user app.

If they don't match, then the user app will display the text of the message and update the stored date stamp on the device.

Of course, the user app will need internet access.

ayuda (help)

The page does not let me log out to start again from another account, how do I do it?

This forum is in English. Follow this link to go to the App Inventor en Español forum: https://groups.google.com/forum/#!forum/app-inventor-en-espanol

Be patient. Development is looking at the problem.

Cheers, Ghica.

This is the way I do it.

Does that not work on a school network for some reason?

Yes, that is the way to do it, but there was a bug that Jeff has maybe fixed in the meantime.

There were at least 5 persons complaining about it.

Compatibility issue with my published app?

It's been a long time since I visited this community. I had published my first app on Google Play 4 months ago, thanks to all help I received here back then. It is with a possible compatibility issue in that app,I am back here.

Recently I got an email from one of the users of the app, Mapboard lite, that he is unable to run it on his device (which he has reported as Yurekha yu, Android 5.1) .

His complaint is : the app initializes, goes to the second screen; but after that when he presses the button that is supposed to open a zoomed map with drawing tools icons, nothing happens; and that if he presses the button twice the button 'vanishes'. Can it be a compatibility issue? If it is, how can I resolve it? (I have never experienced that issue in my devices. But I don't own a Android 5.1 )

If it is alright, would you please try it on your devices and let me know if there indeed is an issue? Here is the Google Play link : Mapboard lite

I have Android 5.1.1 and I do not seem to have a problem, but I do know that there have been problems with 5.1 in the past. Maybe you could build your appagain with the newest version of AI2 and ask that person to try it for you before submitting a new version to the Play Store?

Thanks. It is nice to hear that the app performs alright in your Android 5.1.1.

For building it again, ought I build it from scratch? Or do you think packaging a new .apk file with the same .aia would be enough?

Yes, the old .aia will automatically be converted if needed if you load it and then build an apk from it.

Just worth a try.

How get an answer and add one point?

Hi!! Im working on a project about counting syllables, the thing is I show you the word and you must write in a text box how many syllables the word has.

In the interface I add a text box to write the answer, a button to get the next word and a Label that the function is like score, so I´d like when the person write the correct answer get one point and the text box is empty again to write the next answer, and if the answer is no correct just get the next word but doesnt add points.

I dont know how I can comparate the answer to get the point. I add the screenshot about what I made. Thank you so much!! Any help would be really appreciated.

Captura de pantalla 2016-04-27 11.49.41.png 표시 중

I think it would help you if you add a button to your screen that says "Check answer" or similar. The gotFocus is not so reliable and moreover, you want to check when the textbox loses focus. There is no event for that. Try this, and report back.

About the gotFocus you are right, but I did not know how start it, maybe I can try just with button1, it would be the button1 to get the next word and add the point if the answer is correct. if I add a button "check button" in blocks how can I make it? although I need get the final score in a date base. My problem is how to compare the answer written in the text box with the right syllables in the list made and consequently add one point. Perhaps instead write the number like "math" of syllabes in the list like the right answers I can put the right number like "text".

Captura de pantalla 2016-04-27 13.21.42.png 표시 중

It seems that you are missing some basic knowledge, therefore I should start with this:

Taifun's top 5 tips to learn AI2

http://puravidaapps.com/learn.php

Then: Rename button1 to something more clear (in the design screen), for example btnCheck. The blocks will automagically change too.

Your logic is rather redundant:

if Textbox1 (rename this one too!) = the list selection then ... else...

In your else you are checking the same thing again, but you could just use the else.

The else you have there can never be reached, because either the first then was true, or in your blocks the next then is true.

Further, the when Button1.Click block requires that Button1 is enabled (you cannot click on it otherwise), so this statement is useless.

Also useless is set LabelScore Text to LabelScore text. Here you are setting a field to a value it alsready has.

But... you are making progress!

Thank you so much!! Im gonna try it! i saw a lot of tutorials but I did not see the advanced tutorials that there are in the link you say!

Point of sales

hello, from app inventor beta (Ai1), and now AI2, I created this program, I think I'm done, I hope you like it. It has 39 screens, a lot of code and use 90% of the components of AI2. This is the link:

https://play.google.com/store/apps/details?id=appinventor.ai_jaumetortosavalles.TPVSimpleBarFree

Regards, and thank for equip of appinventor (MIT).

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That is quite an accomplishment for AI2 !

Your is the first app I have seen to get printing from AppInventor working.

If you could donate screen prints of your printing blocks to an online post here,

I would be honored to add them to the FAQ

Yes, I send you two screenshots:

- The first, you can see the number of screens of my app (38 screens).

- The second screenshot, you can see all functions and methods that I've used in the main screen of my app. How you can see, there are a lot of code.

Yes, I send you two screenshots:

- The first, you can see the number of screens of my app (38 screens).

- The second screenshot, you can see all functions and methods that I've used in the main screen of my app. How you can see, there are a lot of code.

Make a list (with join)

Could someone please give me a hand?

I am trying to do a list (name2) as shown below. How else it can be done? Depend of a random pick the outcome of name2 list should be:

1red.png, 2red.png, 3red.png

1black.png, 2black.png, 3black.png

1blue.png, 2blue.png, 3blue.png.

Why you have a component and also a global named nazwy?

Anyway, put that INITIALIZE GLOBAL name2 block that has errors showing, inside the Screen.Initialize block.

Sorry, I mean, put a ADD ITEMS TO LIST block inside the Screen.Initialize block and there you can use that configuration that is not working right now.

It is working now -. I had to also add 'create empty list' so images won't mix.

Anyway thanks a lot for guidance.

Error grave When the application and placed no google play (Serious error When the application and placed in google play)

Good morning, I'm sorry, I is the first time I post on the forum do not know if I'm doing something wrong, I'm from Brazil and my English is not good I'm using google translator, I am coordinator of a team Technovation and my students have made an application for this competition in the test via qrcode the application functioned normally, but put it available on google play, but when you do dowload phones that have the application installed was the phone being in a black screen with the "interface application has stopped working" and the phone to return to work after doing a hard reset, so even after formatted no earlier versions through qrcode though it was the dowload it stopped working again as much of a solution much appreciate your attention porfavor let me know if you get an answer

Did you first install the apk file manually on a device and test it before uploading it to Google Play? Did this work?

Edit text file with MIT App inventor 2?

I'm noob with MIT App inventor 2, i need to download and edit a text file, so i found how to download a file but now i need to edit this file, remove some text and add some text (many and many text it's a big file).

So you can help me to do this ?

Simplest way would be to completely overwrite the file with new content.

Also, consider using other storage components such as TinyDB.

I tried to do something with TinyDB but i don't find how i can do this.

i already created my app for windows, i use Autohotkey to make my app, i use function "String replace" to replace some texts and now i want to create a android version of my app.

So i think i need to use something like "String replace" to replace some texts in my file, we can find something like this in MIT App inventor ?

My windows app works like this :

-> Download the file from internet

-> Save the file in my HDD (named file1.txt)

-> Read file1.txt

-> Replace some texts

-> Save the new file with the new texts in my HDD (named file2.txt)

So i need to do same thing with MIT App inventor.

You can help me please ?

use the file component to read the file and the text blocks to manipulate the text

see the documentation http://ai2.appinventor.mit.edu/reference/components/storage.html#File

and http://appinventor.mit.edu/explore/ai2/support/blocks/text.html

A very good way to learn App Inventor is to read the free Inventor's Manual here in the AI2 free online eBook http://www.appinventor.org/book2 ... the links are at the bottom of the Web page. The book 'teaches' users how to program with AI2 blocks.

There is a free programming course here http://www.appinventor.org/content/CourseInABox/Intro and the aia files for the projects in the book are here: http://www.appinventor.org/bookFiles

How to do a lot of basic things with App Inventor are described here: http://www.appinventor.org/content/howDoYou/eventHandling.

Also do the tutorials http://appinventor.mit.edu/explore/ai2/tutorials.html to learn the basics of AppInventor, then try something and follow the

Top 5 Tips: How to learn App Inventor

You will not find a tutorial, which does exactly what you are looking for. But doing the tutorials (not only reading a little bit) help you to understand, how things are working. This is important and this is the first step to do.

Projects swapped

Hello, I was working on a project and had saved with another name as back-up. Now, when I opened it, I am in shock that the entire project has been replaced by an unrelated one. This is sad, as my 3 months work is lost. Plz help..

I never heard of something like this

usually the recommendation is to backup your work and save aia files on your computer, see also http://twodogapps.com/?page_id=686#BackupWork

it seems to be, you are learning it the hard way why you should backup frequently...

Thanks for the quick reply Taifun. Yeah, learning it the hard way...

But, let me elaborate what happened-

1. I have projects named A, B, C...

2. I saved duplicated of A named Copy1

3. I made some modifications in A (Which ofcourse cannot be Undone)

4. I deleted A in haste (My mistake)

5. Then, I opened Copy1, though the date of creation of Copy1 is today, Copy1 is replaced by B.

Then I logged in and out multiple times and rechecked even using mobile phone, nothing changed.

Anything possible now?

well, most probably you never saved a copy of A, but a copy of B instead

it seems to be, you will have to restart from scratch concerning project A

next time follow the recommendation to download aia files as backup frequently

Getting Memory on my device using android.app.ActivityManager.MemoryInfo

I am trying to pull memory usage into my app. I am trying to use the android.app.ActivityManager.MemoryInfo getMemoryInfo(ActivityManager.MemoryInfo).

Any suggestions on how this method can be called into my App Inventor 2?

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you could write your own extension and create a block yourself following this snippet http://stackoverflow.com/a/3192348

more information about how to create an extension see here https://groups.google.com/d/msg/mitappinventortest/Ip2AX036d0U/5NJlAEbFCgAJ

however that will be more advanced and will require some Java skills...

I can't import aia files anymore!

I just can't import project (aia) from my computer. A window comes and says "I can't have any spaces or disallowed characters". The thing is I use to be able to import projects til one day I must have changed the file type used to open the file, which doesn't make sense cause all the files that I am trying to import all end in .aia.

just rename the file before importing it... use simple names without spaces or special characters, for example mark.aia

Thanks so much! That was it :) I don't understand why it wouldn't work with spaces but that was the problem, whenever the computer makes a copy of a file it adds (1), (2).... This problem should be told to other developers just getting started.

Unzipping .apk & changing AndroidManifest.xml & SDK Level for Higher Resolution.

I've never posted here before, and I wanted to extend my understanding of MIT App Inventor (AI) and I was wondering if anyone here could help...

I understand there is an AppToMarket tool that can help me accomplish this, but I would like to know how to do this without those tools so I can use this understanding to create and modify programs in the future using other Android development tools such as Eclipse / PhoneGap (Cordova)...

The major roadblock that I'm running into involves the resolution restrictions built in to AI, making my projects look pixelated and fuzzy. The same is true with the recommended 48x48 pixel icon. I wanted to create a drawable folder in my .apk so my icons can support more resolutions... I already know how to create the folder structure and the appropriate icons (and will do a writeup in the future about it, if there's any requests)...

Here's what I tried: Unzipped my project .apk with 7zip, and the AndroidManifest.xml file is corrupted. I'm guessing it's either caused by the .apk being zipaligned or the signing of the .apk in AI. Some other issues I have is once I do make the appropriate changes, then I'll need to resign and rezip my project... I'm totally unsure if I'll have to change my SDK when I do make these changes.

So here's what I'm asking:

#1 - How to properly unzip an .apk made by AI

#2 - Do I need to resign the app and how? (do I use the keystore one made from AI to resign?)

#3 - How to zipalign when done? (which I'm guessing is zipalign -c -v 4 example.apk ... -c to confirm the zipalignment, -v is for verbose output, 4 is for 32-bit alignment)

#4 - Does changing my app to use large, xlarge, or fullscreen of the android device - does that change the SDK level of the App?

#5 - If it does change the SDK level, which levels would I choose?

If anyone can give me hints or point me into the right direction, I'll make a nice writeup for people using AI so they can get the most out of this MIT project and post it wherever this group needs it to go (Websites, PDF, whatever).

Thank you for reading, I tried searching for these issues on this Google group, but I found nothing. If there's reposts to any of these issues, I'll be more than willing to look at links. Again, I'd like to learn how to do this manually...

You can't simply unzip the. Apk
The manifest is not corrupted. It's just compiled version that you see.

When compiled and being repackaged, it has to be reSigned with same key.

How to make internal changes to your App Inventor Project

Q: Why would you want to do this?

A: Major reasons would be the following: If you want support for making minor changes to the AndroidManifest.xml file and add higher resolution icons to your project to support higher resolution screens. Supporting higher resolutions allows AI users to create a more professional "Production" application that is more usable by the public. Another reason would be to not use the insecure android.keystore. There are even more advanced things you can do, but it's really outside the scope of this document...

Q: android.keystore? What's that?

A: A keystore is a encryption key that follows the X.509 standard and it uses encryption to make a type of public/private key combination. The keystore is a way to sign your application to show ownership of the application. This is as legal binding as signing a document, and if you use the default android.keystore, it has more potential of being unlocked. (storepass & keypassword are known variables) Google will NOT allow an application to be submitted to the Google Play store without your application being signed and zipaligned. android.keystore is the file that you can import and export within MIT App Inventor 2 under the Projects Menu on the top of the screen.

Q: Why not use the original android.keystore?

a: AI's keystore is insecure because the storepassword, keypassword and alias is the same for ALL AI users. (alias = androidkey; keystore password = android; key password = android) Your keystore is the way you sign your application, saying that you are the developer for that application. If you have already submitted an app you have developed into production with AI2, you unfortunately have to use the same android.keystore. If that is the case, Google Play will force that app to use that same keystore given in AI. Fortunately, you can secure your keystore somewhat by changing the storepassword and keypassword to something new.

Please Note: AppToMarket is a much easier method to create and maintain keystores and is recommended by me for newcomers to Android Development.

Tools needed:

APKTool - for all platforms (Install Instructions) - Needed to decompile & recompile your .apk file

Java SDK or OpenJDK (I used version 7) - Needed to run APKTool, keytool & jarsigner

Android Build Tools from Google - needed for zipalign

Need to do before starting (Windows / very similar steps are probably required in Linux):

⦁ All the commands mentioned above should have their directories linked to the PATH environmental variable, so you can work on your APKs in whatever directories you wish to develop in. (Instructions for most Windows flavors)
⦁ Choose a development folder/directory and copy your AI2 completed folder into it.
⦁ If you haven't already, open your command prompt (either by typing cmd on the search bar or Start -> All Programs -> Accessories -> Command Prompt)
⦁ Move through your directory tree until you get to your development directory. In this case, your tab button is your friend, hitting tab will help you auto complete the names of directories and placing quotes around directories that have spaces. Simple Commands to know: CD (Change Directory: CD .. to go back a directory and CD . for current directory), COPY (COPY file), DEL (DELete file). (Wikipedia Article for DOS commands)

Decompile .APK:

(From this point on, we will call the apk that your working with example.apk... The words in bold with the greater than symbols are the commands your running at your command prompt; don't type in the greater than symbols ;) )

> apktool d -s example.apk

This decompiles your example.apk into a folder named example. (the folder name is always the name of your file minus the extension) the d command is to tell apk tool to decompile your apk, I believe that the -s has to do with the permissions of your app, but to be honest, I'm unsure, I just know I've made good installs using this technique.

AndroidManifest.xml and Icon Changes:

Here's the changes I've made in my own AI2 application to improve the production level of my work, if you have other suggestions to improve AndroidManifest.xml or other files, please share...

Icons: Here's an example of the folder structure if the program that you uncompiled was called example.apk:

example\res\drawable (deleted)
example\res\drawable-ldpi\ya.png (Transparent PNG - 36x36px)
example\res\drawable-mdpi\ya.png (Transparent PNG - 48x48px)
example\res\drawable-hdpi\ya.png (Transparent PNG - 72x72px)
example\res\drawable-xhdpi\ya.png (Transparent PNG - 96x96px)
example\res\drawable-xxhdpi\ya.png (Transparent PNG - 144x144px)

I named all of the files ya.png because that is the default name in AndroidManifest.xml and the name of the PNG didn't really matter to me. Pick icon images that scale well when designing this.

AndroidManifest.xml: This thread posted by Gareth Haylings was exactly the changes I wanted to make to my application. In short, this is what Gareth wrote (with a small addition by me)...

Between the application Tag and the last uses-permission Tag (my decompile didn't have a uses-sdk tag), I added:

<supports-screens android:resizeable="false" android:smallScreens="true" android:normalScreens="true" android:largeScreens="true" android:xlargeScreens="true" android:anyDensity="false" />

android:resizeable is set to false, as android:resizable="true"
has depreciated... I added the support to xlarge screens in this listing...

And in the same thread above, Gareth tells us the technique to remove the title bar, by adding this to your application tag...

android:theme="@android:style/Theme.NoTitleBar"

I used Notepad++ for the changes made. Now that you've made these changes, you'll most likely have to make changes to your program to improve the layout for tablets and high resolution smartphones. The way in which you do this depends entirely on your design philosophy.

Build (Recompile) .APK

Here's if your folder was named example...

> apktool b example example-output.apk

APKTool is experimental and there is no promise that this will work... In fact, this is the point where your program breaks 90% of the time. If you have errors and warnings, it's because of the changes you made in your AndroidManifest.xml or your version of aapt is outdated. (I think sometimes this also can be caused by the framework, each decompile will make a 1.apk on your computer... At the time of this writing, I didn't have a chance to confirm this fact... If you think this is giving you bad builds, delete 1.apk, decompile, make changes, build) Keep in mind, we are making changes to the apk file in ways which were never intended by the MIT team. The only words I can give you is good luck and read the errors very carefully that your program produces. It will be near impossible for people in this forum to help you. I used Notepad++ because the notation of your AndroidManifest.xml file will be colored and you'll see the line numbers of your AndroidManifest.xml files, in case you run into a build error.

Now we are going in two directions, the first is if you already posted your App Inventor 2 app on the Play Store or if you haven't...

If you have already posted your App Inventor 2 app on the Google Play Store:

If that is the case, then you'll should change your keystore password and key password for added protection. You'll also need to Import your android.keystore... (Remember: default keystore password = android, default key password = android, CN=MIT App Inventor email address, O=AppInventor for Android, C=<country that you live in>)

To change your keystore password:

> keytool -storepasswd -keystore android.keystore

To change your key password:

> keytool -alias androidkey -keypasswd -keystore android.keystore

(Note: Pick passwords that are secure, and you only need to do these commands once... You don't need to do this again after this time... keep your keystore password and your key password somewhere secure and your android.keystore secure when done. This is your DIGITAL SIGNATURE!)

If you have HAVE NOT posted your App Inventor 2 app on the Google Play Store:

This is to make a unique keystore for appinventor and also for any other development, like Windows. If you do make other applications, you'll want to have your keystore signed by a CA.

Here is some recommendations to you...

⦁ Your private key should be generated on a SECURE PRIVATE computer!
⦁ Use a keysize of at least 2048 bits (I use 4096 bits).
⦁ Must have a lifespan of at least October 22, 2033, calculating the number of days from April 18th to that day came out to 7128 days.
⦁ Only first 8 characters are used in the alias.
⦁ Use RSA.

Here's Google's recommendations: Signing Your Application

To make a self-signed keystore (named example.keystore with an alias named examplealias, using RSA, 4096 bits, and valid for 7200 days):

> keytool -genkey -keystore example.keystore -alias examplealias -keyalg RSA -keysize 4096 -validity 7200

It will ask for your keystore password, your key password (never use the same!!!), your CN (email address of company), your OU (Department or leave blank), your O (Company Name or leave blank), your L (Town of Company or leave blank), your S (State of Company or leave blank), your L (City of Company or leave blank), your C (Country of your Origin)

More information about keytool by Oracle. You only need to make a keystore once for your application. YOU SHOULD NOT EVER LOOSE YOUR KEYSTORE or FORGET YOUR PASSWORDS, same as above, you've been warned...

---

Signing your Application

Now, use the appropriate keystore to sign your app... In this example, we are using android.keystore, but if you haven't already published your AI2 App, I'd recommend a new keystore....

> jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore android.keystore example-output.apk aliasname

(android.keystore = rename with whatever your keystore file is (it might be the same), and aliasname is whatever your keys alias is...) It's going to complain about time stamping when executing, but that's not important for creating an Android App for Google Play.

Verify your signature:

> jarsigner -verify - verbose example-output.apk

ZipAlign your App

> zipalign -v 4 example-output.apk finished.apk

This makes your file easy to access on the android platform.

Test your APK and Upload to Google Play Store when done!

Resources: Links above + wikiHow + Stefan Diener

Please share your experiences and things that you've learned by decompiling and building your APKs on App Inventor 2, I wouldn't mind learning something new!

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key password and store password

Hi! I need the key password and the store password, to change app to external software. What have idea? .

are you talking about the keystore?

see here Unzipping .apk & changing AndroidManifest.xml & SDK Level for Higher Resolution.

Ping or Rcon

Is there a way to ping servers with in app inventor and get some sort of sign that they are online and would it be possible to rcon into game servers through an application built in app inventor?

you could write your own extension and create a block yourself, see for example this snippet http://stackoverflow.com/a/16458623/1545993...

more information about how to create an extension see here Announcing App Inventor Extension Components

however that will be more advanced and will require some Java skills...

TextBox Background colour

I'm very new at this..so Ill maybe ask lots of stupid questions.
Firstly when in designer I can set the background colour of a textbox to 'none'. In blocks I am changing the background of the textbox to grey when the textbox has GotFocus.. is there a way set it back to 'none' once it has .LostFocus ?

--

Thanks for the reply, you mean use the make a colour and make a list blocks with 16, 777 & 215 ?

no, just use a number block and put that number inside

alternatively use Enis' solution, which you can find after doing a search like this https://groups.google.com/forum/#!searchin/mitappinventortest/color$20none in the first thread here https://groups.google.com/forum/#!searchin/mitappinventortest/color$20none/mitappinventortest/sYC77xotIPA/gM51i3qHFmQJ

Ok cool... sorted now .. just hadn't found the number box before.

2016년 12월 29일 목요일

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