Coding: Best Practices

It is important when writing software, in any language, that attention should be paid not only to the correct functioning of the code, but also to how the code is written and organised. Well written code is easier to understand, debug, maintain, enhance, and test. This can make or break a team software development project, and great emphasis is placed on adherence to coding standards and best practices in software design. It is equally important for solo developers who share their code with an Open Source community, or even when returning to one’s own code written some time in the past.

This document contains some guidelines which may be useful when programming with App Inventor, and which represent practical implementations of widely accepted programming principles.

Web Quiz App

A new app has been added to the UniTY section of the App Library. WebQuiz is a picture quiz similar to the quizzes in the APPlied and Smart Skills sections of the library, but using the Web Connectivity component of App Inventor to dynamically retrieve the images and answers from a web server. Only the minimum functionality to retrieve files from a web server is implemented: error handling and cache control have been omitted in the interest of clarity, but would be necessary for a production app. The sample files were uploaded to the web server via FTP, though creation of a web application to create and administer quizzes would be an interesting project in its own right.

ARC Welder Problems

If you are using ARC Welder to test apps, the latest update (24th March) appears to have caused problems for some users. In some cases, when downloading and installing ARC Welder, the first part completes (download of ARC Runtime) but the second part (download of ARC Welder itself) fails with a "Manifest Invalid" message. In some cases, the download and installation completes normally, but when an APK is loaded into ARC Welder, it crashes with the 'broken plugin' black screen. At this point we have not been able to confirm if these are widespread experiences, or whether a new release is planned to address them.

The workaround that we are using is to install Chrome Portable and use it instead of the normal Chrome browser. Chrome Portable runs the current version of Google Chrome from a self-contained folder, rather than integrating with the OS in the way that a normal installation does. There is no need to uninstall Google Chrome in order to install Chrome Portable. Download it from the green Sourceforge link on this page: http://portableapps.com/apps/internet/google_chrome_portable and run the executable to install. Tick the checkbox to run Chrome Portable after the installation completes. No shortcuts are created. Once this is installed, quit the standard Chrome browser, and continue as normal within Chrome Portable.

Amazon Fire tablet safety notice

Amazon have issued a recall for the power adapters supplied with Fire 7" tablets, and are asking customers to stop using the adapters. They are offering a free replacement service. Please follow the link below for more information.

https://www.amazon.co.uk/b?node=9730244031

Video Branding

All of the Smart Skills videos have had a UniTY splash screen added at the beginning, and the thumbnail for all videos now also displays the UniTY logo. The video content is otherwise unchanged, and the playlist URLs are also unchanged, although individual videos have new URLs.

MIT App Inventor Update

An update to MIT App Inventor was pushed out on 18 February, and users will see a pop-up screen alerting them to this on their first sign-in after that date. None of the updates described in the release notes should have an impact on existing Smart Skills apps, and the changes to the appearance and functionality of App Inventor are minor enough to go unnoticed by most users.

If you have installed the AI2 Companion App on an Android device in order to use the WiFi or USB 'live debug' methods, it will need to be updated to use the new features in this App Inventor release. If you installed the Companion App from the Google Play store, it will update automatically; if you installed it directly to your device, you will need to manually update to version 2.36 at appinv.us/companion.

Hello Again, World!

This blog, formerly the UniTY Smart Skills Development Diary, is being extended to cover developments across the full range of UniTY courses: Multimedia, Smart Skills, Employability Skills, and Student Empowerment. Each article will be tagged with the course(s) to which it applies.

The blog has a new title and new domain, http://blog.unitydcu.ie, but is still hosted on Blogger as that is the most convenient platform for students and teachers to use for their own blogs, being integrated with Gmail and Google+. Links from the old domain are automatically redirected, so there is no need to update existing bookmarks.

As before, access to the blog is by invitation only and is restricted to teachers and guidance counsellors who have engaged with the UniTY programme. With this in mind, we encourage you to comment freely on any articles posted on the blog, and to use it to share experiences and start conversations with your peers in other schools.