Xamarin, with an upgrade to its Mono for Android SDK on Monday, is adding a drag-and-drop, graphical designer for building Android application interfaces within either Microsoft's Visual Studio or Xamarin's own MonoDevelop IDE.

Xamarin Designer for Android is featured in Mono for Android 4.2. Developers can edit properties for native Android widgets and interface controls from within a visual designer and produce standard Android XML layout files. "It produces layouts in the standard Android format - XML format," said Joseph Hill, chief operating officer at Xamarin.

The designer follows conventions of Visual Studio and supports Android API levels going back to level 4 of the Android platform. Also supported are the "Froyo," "Gingerbread," "Honeycomb," and "Ice Cream Sandwich" releases of Android. Developers have  control over form widgets, text fields, layouts, images, and media. Support also is featured for dock-specific layout configurations, including car, desk, and television. Users can view and edit layouts by language, region, country, and telephone carrier.

The SDK, which starts in price at $399, includes the Mono runtime for running .Net applications on non-Microsoft platforms. Also featured in Mono for Android 4.2 are capabilities for integrating Java libraries and the ability to take advantage of recent Android features on older phones. Developers get x86 support, as well, to boost emulation.