Do you wonder how the preview bubble looks in the Widget you are building? You don’t need to have a real phone running Yahoo! Go 3.0. Now you can run Blueprint applications from a desktop Web browser using the Yahoo! Go emulator.

The Yahoo! Go 3.0 emulator is a great way to see how your widget looks and behaves in Yahoo! Go: You can scroll through the carousel, see the preview information, see the different shortcuts (also specified in the config.xml), and try the unique look & feel of the maps component.

First, you need to upload your Widget through the standard test submission process: http://mobile.yahoo.com/developers/test

Then go the the emulator page: http://mobile.yahoo.com/go/tryit

From the emulator, sign in to Yahoo! with the same user ID you used to submit your Widget. Then look for your Widget on the simulated phone. You can see what your Widget looks like in the Yahoo! Go carousel and check the appearance of the visual controls, including maps and location-chooser, in the Go environment.

You can also still test your Widget in an HTML environment, from phone or desktop (we recommended Firefox), by signing in to the Yahoo! mobile beta site: http://beta.m.yahoo.com.

Some small limitations apply for the emulator: Obviously, GPS and cell-ID location won’t work from a desktop browser. And if your application has external links, they won’t work on the emulator (since they are supposed to open in the phone’s native browser).

Trapster, a service that alerts you about police speed traps, has recently updated their Blueprint Widget to use the location-chooser and map controls. With the new version, users can easily find their location by typing it in and getting Yahoo! geo-location results, or by pressing one button to retrieve GPS or Cell ID information (on supported devices).

Once the location has been set or automatically retrieved, the map control displays speed traps around the users location as POIs. By selecting different POIs, the user can get details about the trap, such as the presence of red-light cameras or the number of reports about a particular trap.

The map control provides a full-featured map service including zoom, pan, traffic information, and satellite or hybrid view.

Trapster shows a very good use of two new controls introduced with Blueprint 1.0. The coding required a change in the blueprint.php library that has been published with todays SDK update. Please use the new SDK version if you want to implement the location-chooser using the blueprint.php helper classes. An additional documentation in the SDK provides you with more detailed information on how to use the location chooser control.

Especially if you are using Yahoo! Go 3.0 on a GPS-enabled devices you definitely should try this service. The widget is live in the Widget Gallery.

Thanks to Trapster for building such a great Blueprint Widget!

We just launched an update of the Blueprint SDK. The new sdk.zip contains:

• an updated Blueprint Developers Guide
• an updated blueprint.php helper class with a bug fix related to the location-chooser
• a Quick Start guide for developers who are new to Blueprint
• a guide to the location-chooser control
• an article (adapted from this blog) that provides *guidelines for designing Widget icons

The new documentation will help you to understand the complex location-chooser control. The Quick Start will give you an overview of Blueprint and help you with the Twitter example that comes with the SDK.

Especially if you are working on projects that use location-based services, we encourage you to download the updated SDK from: http://mobile.yahoo.com/developers/download

Our friends from the Yahoo! Developer Network (YDN) published a great article that guides you through the first steps of Blueprint development. The example that is described in the article is a widget that displays RSS content from the YDN blog. It is a great example of how to code a Blueprint widget using PHP/XSLT and pulling data from an existing RSS feed.

You can find the article here: A quick Blueprint how-to - your first widget.