MonoDroid Bridges .NET with Android

| by Abel Avram Follow 9 Followers on Jan 07, 2011. Estimated reading time: 2 minutes |

MonoDroid brings the whole Mono VM to Android, enabling .NET developers to write applications for Google’s mobile OS. Developers now can write applications targeting iOS, Android, and Windows Phone 7.

MonoDroid is a framework similar to MonoTouch enabling developers to write applications for the Android mobile operating system using the C# language and the Mono VM. The MonoDroid API contains the set of core libraries which are contained by Silverlight, except for the UI interface, and a set of bindings to the native Android Java API which are necessary in order to access device specific functionality such as various sensors, cameras, Bluetooth, etc.

In order to develop for Android on Windows, the Visual Studio Professional or better is needed along with a plug-in and an SDK. The SDK makes reference to the Android SDK which in turn uses the Java SDK. Development on Mac OS X is supported from Preview 10 with MonoDevelop, the cross platform IDE developed by Mono. Linux development is planned to be supported soon also via MonoDevelop.

MonoDroid opens the Android world to .NET developers. Using .NET and Mono, one could develop an application for Windows Phone 7, iPhone OS, and Android in the same time, but things are not as straightforward as developers might like. The UI APIs and specific device functionality is different from platform to platform, so one should not expect to write once and run everywhere the same code. The code needs to be clearly divided in business logic and UI-logic, the last part having to be rewritten for each mobile OS. Nonetheless, this is a step forward for .NET developers who want their applications to reach a market as wide as possible.

The roadmap for MonoDroid does not specify when version one will be available, but Miguel de Icaza mentioned they are “are working as fast and as hard as we can to complete Mono for Android.” MonoDroid 1.0 will use Mono 2.8, and will support C# 3.0, .NET 3.5, garbage collection, multi-threading, and other standard features such as LINQ. OpenGL will also be supported through OpenTK API, an object-oriented wrapper for OpenGL libraries. OpenTK is also included in MonoTouch, so OpenGL code can be shared between Android and iOS.

According to de Icaza, MonoDroid is used by the DeltaEngine, a cross-platform game development engine, to run games on iPhone, Android, Windows Phone 7, and XBox 360. Among other demoes, at CES 2011 NVidia presented a game, Soul Craft, running on LG Optimus 2X, an Android phone based on NVidia’a Tegra 2 dual-core chip. The game ran on MonoDroid.

MonoDroid is going to be a commercial product, the price not being available yet. As a reference point, the price for MonoTouch starts at $99 for the Student edition,  goes to $399 for the Professional, and ends up at $3,999 for a 5-seats enterprise license.

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Interesting but.. by Mark N have have some code that is platform specific and it is not OpenSource or freeware. And with the extra overhead, it would seem, of .NET running, what Android devices will you be able to target? If you have the time and money and you really really only want to use VS.NET and .NET, then I can see buying and using it. But then if you only want to use Microsoft products, why are you targeting non-Microsoft platforms? Otherwise, why not use Java and Eclipse or Python?

That being said, I wonder if this will be even possible in reverse - "Java" running on Windows 7?

Re: Interesting but.. by Abel Avram

I see this as an opportunity for companies with large investments in .NET/C#/VB.NET, especially programming expertise, being able to more easily port their WP 7 apps to Android. Same goes with MonoTouch for iOS. It is easy to buy an IDE or another, but it is not easy to get skilled staff for whatever platform you have.

Re: Interesting but.. by Dan Tines

It's not .NET running, it's Mono. My understanding is that (at least on the IPhone) Mono and the program are Ahead of Time compiled into one big binary, thus getting around IPhone's runtime restrictions.

As far as why. Who knows. People want to program in C# instead of Java or Python. Monotouch might have cross-mobile APIs so that you almost target the IPhone and Android without much fuss.

I'm assuming it would be possible to run "java" on a Win7 mobile, since (unlike the JVM running C#), the CLR should be able to handle Java. Now whether anybody would have the inclination to build something like that is another story.

Since Android is a pretty open platform, I'd be curious to see what the breakdown of development languages/runtimes are for the big apps running on it.

Mono's gaming niche by Dan Tines

It looks like Mono is carving itself out a nice little niche in the gaming industry.

Take a look at and

Re: Interesting but.. by Mark N

Yeah, I know Mono is not .NET. I was using it "generically".

The JVM could run C# just as "easily" as Java on the CLR.

The problem is ... Android is an open platform will Win7 is not. That is why MonoDroid was possible.

Not sure, but I think everything must run in Dalvik. Java and Python are just the syntax [currently] used.

Re: Interesting but.. by Mark N

Re: Interesting but.. by Dan Tines

The JVM can't run C# as easily as Java on the CLR because of things like pointers and value types.

Not everything runs in Dalvik on Android.

Re: Interesting but.. by Dan Tines

The problem is ... Android is an open platform will Win7 is not. That is why MonoDroid was possible.

It's not a problem and not why MonoDroid was possible. The Mono guys targeted the iphone first, which obviously isn't "open".

Re: Interesting but.. by Dave Nicolette

IMHO Abel Avram touches on a common misconception about skills transfer and easing into new technologies.

First, "programming expertise" is not the same thing as familiarity with a particular language or platform. "Programming expertise" is not language-specific or platform-specific.

Second, the approach of using some sort of wrapper or emulator as a way to ease an organization into a new technology has been tried many times before, and the results are usually not what people hope for. Differences between platforms tend to be deeper than a quick glance can reveal. Just look back to the days when VB6 programmers tried to move to .NET by writing VB.NET. The differences turned out to be significant, after all. The key "new" element to learn was the .NET environment; hiding the details behind a familiar source language didn't really help. Those who bit the bullet and learned C# were better off. IMHO if you need to support a "new" platform then just use the tools that are made for that platform.

When it comes to phones, the differences between devices are so significant that it may be foolish to hope for a single development environment for all platforms. The logistics of managing a codebase may well be more complicated if we develop a set of common code alongside several sets of platform-specific code than if we develop functionally-equivalent versions of an application for multiple target devices, using the tools appropriate to each target platform.

Re: Interesting but.. by Abel Avram

Hi Dave,
I would say it is clear from the context of my comment that "programming expertise" refers to ".NET programming expertise", i.e. knowing the platform, the language(s) and the tools, and not general programming skills.
Regarding the second remark you make, it is true that using a "native" tool for a platform is best from a developer's perspective, but a business decision depends on many factors. If one can use the entire business logic of a C# application, and just rewrite parts of the UI to make it work on Android, then a manager may decide that it is a sound decision to port that C# application to Android because it saves time and money.

Re: Interesting but.. by Dave Nicolette

Yes, points taken. I just wanted to point out that there is a difference between "because it saves time and money" and "because the manager believes it will save time and money." Shortcuts often turn out to be...not so short.

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