You won’t find too many Google Nexus One smart phones floating around, but the flood of Android-based phones like HTC’s Desire from other vendors continues to overwhelm the competition (Fig. 1). Android is rapidly moving into the tablet and embedded space as well.
Support for Android platforms is available from major embedded tool vendors such as Wind River, Mentor Graphics, and MontaVista. If you’re planning on putting Android on your hardware, then these are the companies to see.
Most developers are likely to be taking advantage of someone else’s hardware, though. In this case, it’s an application development chore that programmers are familiar with. Part of that chore is understanding the underlying interfaces and using the associated development tools, of which there tends to be a wide range of solutions.
For the Android, developers typically have three choices: write a native application using something like Java or C++, write a Web-based application, or utilize a rapid prototype system.
The first option is for heavy-duty applications or for developers who are already well versed in Android, its interface, and its tools. The learning curve is relatively steep for a developer new to Android.
Web-based applications are suitable if connectivity isn’t an issue. This is typically true for the kinds of solutions we are talking about here where Ethernet, Wi-Fi, or Bluetooth are likely to be the network of choice. The embedded device to be controlled would be running the Web server.
Web servers tend to be included in network support for most operating systems. The trick is designing the Web pages for the target device. This is possible but not always as easy as a novice developer might think. HTML 5 will help for some applications needing video.
The Web approach has the advantage of placing few requirements on the control device, other than needing a Web browser. It also means all the application code is kept on the embedded device.
The third alternative is to build a native Android application using a rapid prototyping system. Android has several rapid prototype and design tools available from a number of sources. For example, Adobe’s Fireworks can target various platforms including Android and Apple’s iPhone and iPad.
Another tool from Google Labs, App Inventor, targets developers with little or no programming skills (Fig. 2). Its graphical programming language is based on the Massachusetts Institute of Technology’s Scratch programming environment.
Under the hood, Scratch and App Inventor are written in Scheme, a lexically scoped variant of Lisp. The Lisp code is turned in Java byte codes using the Kawa Scheme framework. Kawa works with a range of Java virtual machines.
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Why Use An Android Front end?
I use a Motorola Droid from Verison Wireless, so this isn’t really a question I ask, but many will. Actually, the question should be more generic: why build your own front end? There are plenty of reasons why you would, from specific hardware requirements to the need for high-speed graphics that might be hard to come by on some Android platforms.
Still, plenty of headless applications could use a graphical front end where Android is more than adequate. These range from TV remote controls to setting the temperature at home. Using Android has the advantage of putting a multifunction device in the user’s hands while not having to supply the device. The downside includes compatibility issues and testing requirements.