Google's Inbox uses open source tools to reuse 70% of code across Android, iOS, web

jeremy · 11-24-2014, 09:55 AM

Quote:

Launching a new app in the mobile age is hard. If you want to reach a wide audience, you usually have to make your client three times at minimum: once for Android, once for iOS, and once more for the Web. Building an app on three different platforms means three times the work, with three times as many bugs to squish. To make matters more complicated, these clients all use different programming languages: Objective-C and/or Swift for iOS, Java for Android, and JavaScript/CSS/HTML5 for the Web.

It's a problem Google decided to tackle when it was developing the recently launched reimagining of Gmail, called Google Inbox. With Inbox, Google adopted a set of tools that allowed it to tame the three-headed platform hydra. The app shares roughly two-thirds of its code across Android, iOS, and the Web.

These three platforms share most of the back-end logic that powers the app, while the unique parts are mostly the user interfaces for each app. That gives Inbox a native feel and OS integration on each platform. Google has built itself a good enough arsenal of cross compilers that it can write an app's logic once for Android—in Java—and can then cross-compile to Objective-C for iOS and JavaScript for browsers. Java-to-JavaScript is handled by the Google Web Toolkit SDK, which has been around for some time. The real enabler for Inbox is called J2ObjC, which, as the name implies, converts Java code meant for Android into iOS-ready Objective-C code.

J2ObjC is a open source project which Google went public with last year. The project was previously used in Google Sheets (the spreadsheet part of Google Docs), but Inbox is Google's biggest use of the project to date.

More at Ars...

--jeremy