Gesture Search from Google Labs now has an API, that you can use to easily integrate Gesture Search into your Android apps, so your users can gesture to write text and search for application-specific data.
"It allows you to quickly find a contact, a bookmark, an application, or a music track from hundreds or thousands of items, all in one place. For e.g., a mobile ordering application for a restaurant might have a long list of menu items; with Gesture Search, users can draw letters to narrow their search, explained Google.
Another way to use Gesture Search is to enable users to select options using gestures that correspond to specific app functions, like a touch screen version of keyboard shortcuts, rather than forcing hierarchical menu navigation.
To use the Gesture Search API, you must be sure Gesture Search is installed. To test this condition, catch ActivityNotFoundException as shown in the below code snippet and display a MessageBox asking the user to install Gesture Search.
Gesture Search currently recognizes the English alphabet and numbers. It requires Android 1.6 or above.