AI2 Power Users Frequently Asked Questions (FAQ) Part 1 (A-M)

[Abraham Getzler]

This thread is obsolete.

Please see

https://groups.google.com/d/msg/mitappinventortest/2cd6Uz__xA0/cPQSiZpcDAAJ

ABG 8/14/19

Welcome to the App Inventor 2 Power Users FAQ Part 1 (A-M)

Frequently Asked Questions about programming in MIT App Inventor 2, and answers to those questions or links to sites that answer those questions.

Purpose of this FAQ

This is a supplement to the official discussion group for AI2 . When adding content, please add links to the original content in the discussion group, to avoid duplication. Gathering links here under headings is meant to aid people who don't know how to search yet.

How To Ask Questions The Smart Way  - Eric Steven Raymond

How to post your code - Chris Ward

Activity Starter

• How to find the Activity for an app - Pavitra

• How to download and install another app using the Activity Starter - Taifun

• How to update/run/delete another app using the activity starter - Taifun, Horst Schulze

• View a YouTube video full screen

• How to view a pdf document

• Instagram starter - Shahrooz

• AndExplorer File Picker example

• How to set up Activity Starter using Logcat

• Activity Starter Catalog Sample App

• Use activity starter to launch OpenStreetMap so that it allows you to import and display a GPX file

• MapsMe Activity Starter parameters

Ads (See Monetization)

Advice

• Tips & Tricks - Chris Ward
• How to post images or aia files to this Forum and how to get advice - SteveJG
  
• BACK UP YOUR WORK WITH AN AIA FILE!!!
  
• Use different screens wisely
  
• use images whose size matches the size you want them to appear on your screen
  
• Don't Repeat Yourself
• SteveJG's Monster List of Tips and Techniques
• How to overcome the App Inventor project limit of 10 MB
  
• How to load lots of text without crashing AI2

Android 5 (Lollipop)

• App Inventor Classic apps don't run on lollipop

APK tools

• Extension: Install app. Notify to user of a new version has come out - Juan Antonio
  
• Change apk name - SteveJG
  
• Common apk modification tools - Boban
  

App Inventor Accounts

• New Gmail address replaced all my MIT APP Inventor Projects - Patton
• Not logging in...
  

App Inventor Forums

• (see Forums, below)

App Inventor Issues

• release notes

• nb178 lost from Blocks Palette: Break, bitwise (but can Typeblock them)

• nb178 Cannot read property 'pb' of undefined error 

• nb178 procedures lose their parameters - SteveJG

• nb178 Speech Recognizer After Getting Text error

• nb178 Blocks Palette errors

• nb178 WebViewer Appearance

• nb176 Build -> QR Code does not  transfer to the device. It just pops us an internet browser..

• nb176 Why App Inventor is mixing three different languages in the blocks interface?

• nb176 interface component: Switch => App Crash
  

• Chrome Won't Download Exported .aia Files

• December 2018 changes - MIT

• ai2.appinventor.mit.edu build problems 9/21/2018 - E Patton @ MIT

• BackPack poisoned by references to removed extension

• Build Error 500  8/7/2018

• Accelerometer/Orientation Sensor/Pedometer crash
  

• apk crashes immediately, after nb165 Themes build
  

• Google Voice stopped working

• http://code.appinventor.mit.edu/ - avoids some AI2 app Engine size limits - J Schiller

• Huawei P9 Lite with Android 6.0 Companion Connection Problems when installed on SD Card

• App Inventor Other Versions - Taifun

• Server Is temporarily Unavailable - Akshay

• Chrome cleanup tool

• Can't delete components

• AI1 Conversion Tool and Shutdown Notice

• AI2 Issues List

• Excessively long text in text blocks breaks project build

• Null Characters in text blocks break projects

App Inventor Versions

• Google Sheet with all the components of App Inventor, AppyBuilder, Makeroid and Thunkable - Peter
  

• code.appinventor.mit.edu for large sizes

• App Inventor Other Versions - Taifun

• AI2Offline - ramiro-pa

• (see Forums section for more)

Arduino

• Arduino serial input basics

• Arduino serial commands reference

Arduino and Wifi

• ESP8266 Controlled with Android App (MIT App Inventor) - Randomnerdtutorials.com

Battery

• Battery Manager Extension - Taifun ($)

BlockChain

• https://docs.thunkable.com/blockchain
• http://appinventor.ethereum.org/
  

Blocks Editor

• Sharing Blocks Though github.com - ABG

• Searching in the Blocks Editor - Ghica

• Blocks Editor needs Browser Popups for Typeblocking and Downloaded Blocks Images

• Finding hidden error or warning icons using Chrome Web Browser Inspector - TFO
  

Bluetooth

App Inventor 2 supports two versions of Bluetooth: the older, < version 4, and the newer Bluetooth low energy, usually called BLE.

For the older Bluetooth protocol there exist two components, BluetoothClient and BluetootServer. In practice you will always use the Bluetooth client to communicate with an Arduino board or similar.

Documentation for the BluetootClient component (for BT<4) can be found here: http://ai2.appinventor.mit.edu/reference/components/connectivity.html#BluetoothClient

MIT provides an extension to use the Bluetooth Low Energy (BLE). Since June 19, 2017 the support for BLE has been greatly expanded and improved. A starting point for finding documentation, tutorials and more is the: App Inventor IOT site

Many examples for BLE are still using the old extension, which has restrictions and bugs, so watch out for these!

• Which Bluetooth protocols are supported? (discussion)

• Bluetooth error codes

Bluetooth < version 4 (using the BluetoothClient component)

•  How to Enable Bluetooth

•  A simple Bluetooth Chat

• Reconnecting Bluetooth across screens

• Reprogrammable SNES Ltd. Control - Kon

Bluetooth < version 4 (using the BluetoothClient component) and Arduino

• DHT22 Temperature or Humidity, no Clock - kio4.com
  

• Delimiter usage for receiving one message per ReadText

• Sending Slider Data to Arduino - Neil Kenyon

• How to type special characters:  CR = \r, TAB = \t, NewLine = \n

• How to send CR the hard way

• Martyn Currey:

• Turning a LED on and off with an Arduino, a HC-06 and Android

• Turning a LED on and off with an Arduino, Bluetooth and Android. Part II: 2 way control

• Turning a LED on and off with an Arduino, Bluetooth and Android. Part III 3 LEDs and 3 Switches

• http://www.martyncurrey.com/android-mit-app-inventor-auto-connect-to-bluetooth/

•  Instructables YouTube course on Arduino/AI2 - Magesh Jayakumar

•  http://mitappsinventor.blogspot.com/  Magesh Jayakumar

• Arduino via USB

• Arduino USB - Pavitra and Thunkable

• Martyn Arduino Bluetooth sketch

• Arduino HC-06 tutorials

Bluetooth < version 4 and OBDII

ELM327 and OBDII AI2 programming

Bluetooth/BLE for App Inventor NB158 (June 19, 2017) and later

• BLE extension Build 20181124

• BLE version numbers

• BLE Extension docs

• BLE extension: http://iot.appinventor.mit.edu/assets/resources/edu.mit.appinventor.ble.aix

• BLE app freezes then crashes - registered too many times - Patton

• BLE heart rate/thermometer work flow - Gerrikoio

• BLE connection on Alcatel requires Google Location turned on - Tim Baudermann

Bluetooth/BLE and Arduino 101

• Arduino 101 Intro - MIT

• BLE LED Controller | Feather 32u4 Bluefruit LE + MIT App Inventor - gerrikoio

Bluetooth/BLE and HM-10

• http://www.martyncurrey.com/arduino-hm-10-and-app-inventor-2/

Bluetooth Starter Guides

• Links to bluetooth guides on communication, numeric data and arduino
  

• How to get Device Information

Bluetooth/BLE and micro:bit

• Micro:bit extension. This extension expands the generic BLE extension

• http://iot.appinventor.mit.edu/assets/resources/com.bbc.microbit.profile.aix

• If you want to just try it out instead of building an app from scratch, here are pointers to sample projects for the LED matrix and temperature sensors:

1. LED overview: http://iot.appinventor.mit.edu/#/microbit/microbitled, project: http://iot.appinventor.mit.edu/assets/samples/MicrobitLED.aia

2. Temperature overview: http://iot.appinventor.mit.edu/#/microbit/microbittemperature, project: http://iot.appinventor.mit.edu/assets/samples/MicrobitTemperature.aia

·       

Bluetooth/BLE Obsolete stuff

• ·         BLE extension .aix download link (Obsolete)

• ·         BLE built app permission error (Obsolete)

• ·         BBC MicroBit example (Obsolete) - Neil Kenyon

• ·         How to send Beewi multibyte hex strings to BLE (Obsolete) - George Loungos

• ·         article about a heart rate monitor and App Inventor working with Arduino/genuino 101 (Obsolete) - Nunez

Books, Tips, Tutorials on App Inventor 2

• Education, Course Materials - MIT

• Android App Inventor DIY Book PDF - Teddy Brask-Andersen
  

• Educational App Development Toolkit for Teachers and Learners - Abeywardena, Ishan S
  

• SFUSD Online App Inventor curriculum

• Quizly - Ralph Morelli Trinity College live exercises

• Taifun's Top Tips for Learning App Inventor

• Create your own Android Apps - Wolber, Abelson, Spertus, Looney (Online book)

• Structure and Interpretation of Computer Programs - Abelson and Sussman

• App Inventor 2 tutorials at MIT

• Thunkable Starter YouTube Tutorials Series

• App Inventor Help board

• NFC Tutorial

• SMS Texting tutorial

• YouTube AI2 video tutorials

• How Do You - Wolber

• Ferguson archive (inactive)

• Ferguson archive Google drive

• Truston Teaches Tech - Android development with AI2

Build Errors

• Reserved words that will break your build - SteveJG

Calendar

• Alarm Extension - Taifun

• Add an Android Calendar Event extension - pepemont

Canvas, Sprites, Balls, Animation

• (See Images section for Images)
  

• Pixelation - Italo

• Flood Fill - Scott Ferguson

• Color extraction - Scott Ferguson

• Canvas larger than screen - Scott Ferguson

• Multi Touch

• Sprite Cannibalism

• Why don't my sprites collide?

• Gradients sample  - Italo

Charts and Graphs

• Plotly JS file to display real time data - Giriraj Pawar
  

• ChartMaker Extension - Kager & Manning

• ChartMaker extension decoded - TimAI2

• Scrolling Graph of potentiometer via BlueTooth - kio4.com

• Scrolling graph - Martyn_HK

• Donut/Pie/Radar graphs - Alejo Arué Ocampo

• Plotting sin, cos, tan - Scott Ferguson

• Line Graphs using Blocks - Ryan Cheung

• Chart..js examples / Spanish / Juan Antonio

• How to generate an animated Pie Chart using the Chart.js library

• Gauge Charts

• Torus charts using Draw Arc block - TimAI2

Chat

• Local subnet chat - kio4 Juan Antonio

• Pubnub interface chat example - Taifun

Chromebooks

• Chromebook AI2 on ArcWelder - TimAI2 Feb 2017
• Class with Chromebooks - Patton, jis

Clock

• How to keep app running after screen goes off - Taifun

• Multi-day timer display - Ergin

• Countdown timers

• datetime formats

• How to get UTC with datetime format Z

CloudDB

• CloudDB Blocks Help
• CloudDB Pizza Party remix - TimAI2
• Redislabs account config in AI2 - TimAI2
• HOWTO: Setup a Local Redis Server for CloudDB - TimAI2
  

Companion and Emulator

• Companion Versions 2.53 vs 2.53u usage and improvements
  

• Improved emulator setup - Troy Kozee

• Companion 2.48 bugs

• URI is not absolute trying to read a Media //filename

• Companion changes December 2018 - MIT

• Emergency Companion 2.47 download link

• Where to get the Emulator - Windows

• Connecting to App Inventor Emulator and Updating Companion - YouTube

• Switching to Landscape in the Emulator Ctrl-F11- Juan Antonio

• Screen switching limitations in the Companion and Emulator

• Debugging issues in running the App Inventor Setup Tools and the emulator on Windows (HAL)

• Android Studio emulator with AI2

• AI2 Silent Install Flags

• Companion .apk link to MIT

• Emulator locked with passcode

• Emulator get stuck

• How to run apk on Chrome with ARCWelder - Obsolete, Chrome dropped Apps.

• GenyMotion compatible non-ARM Companion link

• How to use Genymotion with AI2

• More on GenyMotion install

• Microsoft's free Visual Studio Android emulator

• How to use Logcat

• Ubuntu 10.04 instructions - SteveJG

• WiFi emulator connections

• YouTube video on Emulator Fix from Task Manager

• Galaxy S7 USB connection needs RNDIS (USB-Ethernet) (not MTP) developer settings - TFO

Compilation Problems

• Can't complete compile to .apk

• http://code.appinventor.mit.edu/ - avoids some AI2 app Engine size limits - J Schiller

• How to overcome the App Inventor project limit of 5 MB - Taifun

Components

• http://community.appybuilder.com/t/extension-dynamiccomponent-extension/859

Contribute

• http://crowdfund.mit.edu/appinventor
  

Crashes

• Startup crash - images too big - Chris Ward

• Startup crash - player volume > 100

Debugging

• Testing techniques, including DoIt - MIT

• 'Do It' to view procedure results, event arguments and local variables

• How to use Do It in a loop

• How to run Logcat

• Screen1.ErrorOccured message numbers

• SteveJG monster list of things you should not do

eMail

• IFTTT Email - Taifun

• How to send mail

• How to send an email attachment - Taifun extension

Extensions

• How to create an Extension - HAL

• AI2 Extensions forum

• AppyBuilder Extensions

• Extension Directory - Thunkable

• https://puravidaapps.com/extensions.php

• AppyBuilder online extensions builder IDE - Amerkashi

• Kodular online extension builder IDE

• Thunkable extensions announcement

• Microsoft Emotion Recognizer

• Microsoft Image Recognizer- Thunkable

• Notification Extension - Qiang Wei

• SMB Manager - Jörg Hüneburg

• How to create an extension - WEI QIANG

• How to create an Extension - Sander Jochems

Files

• How to test if Image File Exists without using an extension - TimAI2

• Load files at runtime - Taifun

• Asynchronous File Mover/Copier Extension - Taifun

• File to Base64 String Extension - Juan Antonio

• Directory Explorer Extension - Juan Antonio

• WebViewer Extension File Downloader - Sivagiri Visakan & ILoveThunkable

• How to tell if File exists

• Web Viewer File Paths for Development and Production using TaifunTools

• AndExplorer File Picker Sample

• Create folder and files on first launch (avoiding error 2101)

• File Naming

• How to Load Google Drive Files into your App

• Read a File from SD Card

• Save and load a CSV Table

• Error 701 - Space in Directory Name - Taifun

• How to create a PDF file - Taifun

FireBase

• FireBase component help

• FireBase Pending Failure Warning - JIS

• Firebase status dashboard - Google

• Limit your free plan usage - droidim

• Firebase Chat sample - Amerikashi

• FireBase Image Storage and retrieval (extension) - Yaniv

• Firebase Spanish tutorial - lio4

• Firebase bus route tutorial - Romin Irani

• Firebase WhatsAppInventorMIT chat project - Montes

• Uploading Files to FireBase - Thunkable forum

• Brief Intro to Cloud Data and the FireBase Component - HAL

• Using your Own Firebase Account with MIT App Inventor - jis

Focus, Focus ...

• How to automatically jump focus to the next input text box - Thunkable forum via jimdo

• How  to force loss of focus on a text box - nagyd63

Fonts

• Extension to control TTF Fonts in an Arrangement - KIO4.com

• Custom fonts video - PixiiBomb

• Custom fonts and how to Swipe in App Inventor WebView - Bo Kalvslund

For Hire (sites offering paid help (YMMV))

• http://appybuilder.com/

• http://puravidaapps.com/contact.php (currently not available for projects)

• http://nmd-apps.jimdo.com/contact/

Forums

• App Inventor questions, help, hints, support (this forum)

• App Inventor release announcements

• App Inventor Extensions

• App Inventor Open Source (for bug fixing AI2 itself)

• AI2Offline - ramiro-pa

• AI2U - Krupong

• AppToMarket

• AppyBuilder

• Thunkable

• App Inventor Instructors

• App Inventor en Español

• AI2 Internet Of Things Forum

• Kodular (formerly Makeroid)

• Programming with App Inventor (dead since 2014)

• App Inventor Coffee Shop (dead since 2014)

• This forum is spamming me

• (What did I miss? - ABG)

Fusion Tables

• Notice: Google Fusion Tables Turndown

• Fusion Tables Alternatives - SteveJG

• Fusion Table Control AI2 Help

• Pizza Party tutorial

• A complete simple login example using Fusion Tables - Taifun

• Batch Multiple INSERTS per Query - ABG

• Web Viewer doesn't show current Fusion Table Data

• Fusion Tables Row and Query SQL Reference

• Fusion Tables Quotas

• Common Fusion Table Errors

• ROWID not accepted in UPDATE

• What goes under "under the hood" in Fusion Tables?

• Computer scheduling problem

• Google doc with Service Account creation details

• Fusion Tables Service Account Method - Taifun

• Short version of Service Account Method

Generic Events

The notAlreadyHandled parameter

Google Play Store

• APK not optimized problem
  
• Can I make Instant Apps? - TimAI2
• How to Upload to Google Play - MIT
• Upcoming Jan 9 2019 Phone Call and SMS restrictions - SteveJG
• Making an App auto-updating - Taifun
  
• Lost my keystore - SteveJG
• API Level requirements - SteveJG

Google Sheets

Google Sheets compendium - SteveJG

(Also see Web Services section of FAQ https://groups.google.com/forum/#!msg/mitappinventortest/2F51UhB4z0A/IcuCSPpOAgAJ) 

GPS and GeoFences

• Can I turn on GPS? - SteveJG

• Setting up GeoFences

 Icons

• Icon size, Icon generator - SteveJG, oaltair
• romannurik icon generator - BodyMindPower, TimAI2

Images

• Component to Image Extension - Jerin Jacob

• Images in Google Drive - TimAI2

• Image to/from Text Base64 Converters - Sivagiri Visakan, Juan Antonio

• Image Picker Extension 1000 images - Juan Antonio

• Image Picker based on Activity Starter and wild card - Taifun

• Image Cropping extension - ILoveThunkable

• Image manipulation extension - Mika

• Pedroza Thumbnail extension

Installation

• Using MIT App Inventor in school networking environments - current

• An older wide ranging thread on School Networks

Internationalization

• Chinese App Inventor site

• Video Tutorial: How to Support Multi language in App Inventor - Eduardo nuno hernandez

• Contact the Translators of AI2

• Build your own Byte Order Marker (BOM)

iOS

• AI2 IOS support timetable forecast - Farzeen
• http://crowdfund.mit.edu/appinventor
  

Java

• App Inventor to Java

JavaScript Stunts

• Create Buttons in WebViewer By Code - Juan Antonio

• How to fill out a form of a webpage and click a button using some JavaScript - Taifun

• Python and Skulpt thru JavaScript - Taifun

• Sound Generator using JavaScript (Spanish) - Juan Antonio

• ListViewer Selection in a WebViewer Table - Taifun

• JavaScript Date Picker (Spanish) - Juan Antonio

• Dynamic Expression evaluation - Akshay

• OCR using JavaScript Tesseract - Jörg Hüneburg

• Sort a list using the WebViewer - Taifun

• Multiple Input to Pythagorean Triangle Formula - Juan Antonio

• (also see Web Viewer section)

JSON

• JSONTools extension - Luke Gackle

• Blocks based JSON Filter and Lookup - ABG
  

• Blocks based JSON Browser - ABG

• Web Component – JSON Response On App Inventor - Sajal Dutta

• Extracting data from JSON text

Limits

• Graphics File Size Limits

List View (see ListView)

Lists

• MIT Lists Help

• Lookup in list of Ranges - Amerkashi

• Pairs Library - Scott F

• High Score List - ABG
  

• How to create a nested List Picker

• How to work with Lists

• How to shuffle lists

• How to sort lists - Italo

• How to Sort Lists - Taifun - WebViewer

• Sort lists by extension ($) - Jimdo.com

• Object Manager extension ($) - Jimdo.com

• Sort Lists in blocks - Sajal

• CSV Table to File and Back

• How to pick a random item from a list without picking duplicates?

ListView

• Customizable ListView Filter Bar - Italo

• How to reset a ListView Selection - Supermango

• Listview with dynamic images and text - Bo Kalvslund

• ColinTree Custom ListView image/text Extension

Login

• Login with TinyDB, single user - ABG

• Login with Google Oauth - Diego Barreiro

• A complete login example using a Fusion Table as simple as possible - Taifun

• A Login Template by eixerits

Maps

• OpenStreetMap without a Map Component - SteveJG

• How to Build a Circular GeoFence - SteveJG

• Map component tutorial - MIT

• Maps component starter sample - SteveJG

• Offline Flat Map Coordinate conversion - SteveJG

• Breadcrumbs on Google Maps - CoderDojo

• How to save and show waypoints on a map - SteveJG

• Google Earth from Activity Starter

• MIT Google Maps Tutorial

• Google Maps Route from Activity Starter - SteveJG

• Images on Maps Markers - Borgonovo, SteveJG, TimAI2

Math

• Math blocks help (scroll down to see animated pulldowns)

• Generate different random numbers in a range - extension - Juan Antonio

• Generate different random number in blocks

• ASCII Conversion - Italo

• ASCII Table Binary Conversions Video - Pixii Bomb

• Commas as decimal separators?

• How do I subtract an integer from a variable?

• The Log() block returns wrong answers

• How do I get log10() ?

• Displaying Math Formulas with jqMath - Juan Antonio

• Math expressions extension$ - Taifun

Memory Usage

• Reduce the memory usage of your images - Italo

• Using Images with App Inventor - MIT

Mistakes

• Looking for Numbers in .NumbersOnly
• The Impatient '='
  

Monetization

• Admob - Thunkable

• Billing Extension - Taifun

• Monetize your apps - Patton

• Monetization - Makeroid, AppyBuilder

Part 2 (N-Z)