Ever since we started building the Ubuntu SDK, we’ve been trying to find ways of bringing the vast number of Android apps that exist over to Ubuntu. As with any new platform, there’s a chasm between Android apps and native apps that can only be crossed through the effort of porting.
There are simple solutions, of course, like providing an Android runtime on Ubuntu. On other platforms, those have shown to present Android apps as second-class citizens that can’t benefit from a new platform’s unique features. Worse, they don’t provide a way for apps to gradually become first-class citizens, so chasm between Android and native still exists, which means the vast majority of apps supported this way will never improve.
There are also complicates solutions, like code conversion, that try to translate Android/Java code into the native platform’s language and toolkit, preserving logic and structure along the way. But doing this right becomes such a monumental task that making a tool to do it is virtually impossible, and the amount of cleanup and checking needed to be done by an actual developer quickly rises to the same level of effort as a manual port would have. This approach also fails to take advantage of differences in the platforms, and will re-create the old way of doing things even when it doesn’t make sense on the new platform.
NDR takes a different approach to these, it doesn’t let you run our Android code on Ubuntu, nor does it try to convert your Android code to native code. Instead NDR will re-create the general framework of your Android app as a native Ubuntu app, converting Activities to Pages, for example, to give you a skeleton project on which you can build your port. It won’t get you over the chasm, but it’ll show you the path to take and give you a head start on it. You will just need to fill it in with the logic code to make it behave like your Android app. NDR won’t provide any of logic for you, and chances are you’ll want to do it slightly differently than you did in Android anyway, due to the differences between the two platforms.
To test NDR during development, I chose the Telegram app because it was open source, popular, and largely used Android’s layout definitions and components. NDR will be less useful against apps such as games, that use their own UI components and draw directly to a canvas, but it’s pretty good at converting apps that use Android’s components and UI builder.
After only a couple days of hacking I was able to get NDR to generate enough of an Ubuntu SDK application that, with a little bit of manual cleanup, it was recognizably similar to the Android app’s.
This proves, in my opinion, that bootstrapping an Ubuntu port based on Android source code is not only possible, but is a viable way of supporting Android app developers who want to cross that chasm and target their apps for Ubuntu as well. I hope it will open the door for high-quality, native Ubuntu app ports from the Android ecosystem. There is still much more NDR can do to make this easier, and having people with more Android experience than me (that would be none) would certainly make it a more powerful tool, so I’m making it a public, open source project on Launchpad and am inviting anybody who has an interest in this to help me improve it.