xaif

Run your MIT App Inventor projects on (nearly) any operating system!

This tool is in an early development phase, see the disclaimer below.

Prerequisites

You will need to have Flutter installed (https://docs.flutter.dev/get-started/install).

Flutter is an open-source cross-platform app development framework. This tool is built with Flutter, but more importantly this tool will transpile your app into an (intermediate) Flutter app, that can then be compiled for different operating systems.

Important: you will not need to actually write any Flutter code yourself, you just need to have Flutter installed so this tool can use it under the hood.

Also important: you only need to install Flutter (and possibly other dependencies) on your development machine. Any executables you built can be installed/run on other devices without installing any dependencies. (Just like you can distribute your apk)

Please follow Flutter's installation guide (depending on your computer's operating system). You will need to complete the "Get the Flutter SDK" step.

Flutter's setup guides will include additional setup steps (e.g. "Android setup", "Web setup"). You only need to complete these steps if you want to later compile your app for the respective platforms. (I.e., if you want to compile your app into a web app, you need to complete the "Web setup" step).
You will always need to complete the setup step for your operating system. For e.g. if you want to run xaif on Windows, you need to also complete Flutter's "Windows setup" step (because xaif itself is also a Flutter app).
(In the future, a command-line tool could be made available, which wouldn't require this last setup step).

Make sure that Flutter is correctly set up by running flutter doctor in a shell.

Available platforms

Depending on your computer's operating system, the choice of platforms will vary. E.g. if you are on a Windows computer, you won't be able to compile your app for iOS.

Download

Please note that xaif has only undergone (limited) testing on Windows and Linux (Ubuntu). It should in theory also work on macOS, but this hasn't been tested, yet.

To get xaif, you can either clone this repository with git, or download it as a zip-file from Github (green button titled "Code") and unzip it to any location. Then open a shell in the location where you cloned/unzipped the repository and run flutter run. (This will require you to have followed the setup steps for your operating system in the Flutter installation guide. E.g. if you want to run this tool on Windows with this approach, you need to follow the "Windows setup" step in the Flutter installation guide)

Alternatively, you may be able to use prebuilt binaries of xaif from the CI. They are available from the releases page (as Assets) or from any successful CI Workflow run (as artifacts). Use them at your own responsibility! You may be able to use these prebuilt executables to run xaif without completing the "Windows setup" or "Linux setup" step in the Flutter setup, but you still have to complete the basic Flutter setup!

Usage Guide

Export your project from App Inventor as an AIA file.

After starting xaif, select an AIA-file (exported project).
xaif will now create a new project folder in your system's temporary files directory.
Then it transpiles the code (and assets) from the AIA-file to Flutter code and writes that to the new project directory.
Afterwards you are presented with multiple different options to review the generated Flutter code, run your app on different devices or build executables for different platforms (operating systems).

The run options are a good choice to quickly test your app on different "devices" (somewhat similar to App Inventor's Companion), while building your app results in an executable file (or directory of multiple files), like an APK for Android.

While your app is running, you can also update the project by selecting a new AIA file (new version of your app). Any running instances of your app should update nearly instantly (for web apps, you'll need to reload the page).

After you have built an executable you can also launch it (or manually copy it from the project directory to store it).

(Under the hood, this uses Flutter's functionality for compiling and running apps.)

Please note that your operating system may at any time delete temporary files, including the project directories created by xaif. If you want to back up the project directory, simple copy it to another location (you can see the location of the project directory in the tool).

Please also note that every time you launch xaif, a new project directory is created. If you want to use xaif for different projects, it is recommended to close and reopen xaif to actually create a new project directory (otherwise the files from the old project are overwritten).

xaif does not delete its project directory, unless you explicitly tell it to. If you want to save storage space you should delete project directories that you don't need any longer.

Compiling an *.exe for windows

If you want to build your app for windows (build an exe-file) you may need to

a) Turn on developer mode on your Windows machine (recommended by the Flutter team)

b) OR go to the project directory once (path is displayed in the tool), open an admin command prompt and run flutter build windows

The reason is that this tool uses Flutter plugins for many components, and Flutter cannot (at this time) build windows executables with plugins if developer mode is not turned on (or the build has not been run as admin).

It is (as always) your responsibility to review the code generated by this tool and decide if you are comfortable building it in an admin shell!

Status

• Only single-screen apps supported
• Some special Screen1-properties not supported
  • e.g. only Material Theme is supported

Builtin blocks

• Control: complete, except blocks related to dictionaries and multi-screen
• Logic: (mostly) complete
• Math: (mostly) complete
• Text: (mostly) complete
• Lists: complete, except lists_to_csv_table,lists_from_csv_table, lists_lookup_in_pairs
• Dictionaries: (mostly) complete, except advanced methods
• Color: (mostly) complete
• Variables: complete
• Procedures: complete

Components (including their methods)

• UI: complete except ListPicker, WebViewer & possibly some attributes on some components.
• Layout: complete (Change: TableArrangement is scrollable)
• Media: only Camera, Camcorder, ImagePicker
• Drawing/Animation: none
• Maps: none
• Sensors: only Clock (limited)
• Social: Sharing, Texting and PhoneCall (but no direct messages/calls; no intercepting of messages/calls)
• Storage: complete, except CloudDB
  • File does not have functionality for Delete, Append, LegacyMode
  • NB TinyWebDB may not work correctly in web browsers, if the used web service does not run on https (like the default one)
• Connectivity: none
• Mindstorms: none (will not implement due to lack of Mindstorms equipment)
• Experimental: none
• Extensions: not yet supported

Plugins / Licenses

Depending on which components your app uses, (the code generated by) xaif may use different Flutter plugins. You should make sure that you obey all licenses of these plugins and of Flutter. To help with that, this tool will add an "About" entry to the AppBar's overflow menu ("three dot menu"), that opens an about dialog. That dialog contains information about this tool, about your app and the option to open a licenses page with some information about all plugins and their licenses (generated automatically by Flutter).

Disclaimer

This tool is in an early development phase and not very well tested.

It is your responsibility to check the code generated by this tool and use this tool with caution.

Please check the LICENSE file, and especially note the following parts of the LICENSE:

15. Disclaimer of Warranty.

THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

16. Limitation of Liability.

IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

Security

(Where possible) it is always advisable to review code you are running, which includes code generated by this tool.

In addition to all the above, you should only use this tool with AIA-files that you trust. I cannot exclude with certainty that it may in some cases be possible for an attacker to insert malicious Dart code into the generated Dart code, if you use a malicious AIA-file from an attacker.

Acknowledgements

A huge thank you to the team at MIT App Inventor, for creating, maintaining and continously improving the App Inventor, which I consider one of the greatest tools to teach programming and app development!

And similarly thank you to the Flutter team for creating their great cross-platform app development framework!