
We saw glimpses of this at Google I/O, and developers can now make their apps searchable through Google Voice Search. It only takes a few lines of code. Once added, apps can receive the SEARCH_ACTION intent containing the SearchManager.QUERYextra with the search expression.
Examples of such searches might be “Ok Google, search pizza on Eat24” or “Ok Google, search for hotels in Maui on TripAdvisor.” Imagine the possibilities.
Also, users now have the ability to enable OK Google hot-word detection from any screen, which gives them access to apps even quicker.
Android devices must be on the English local, running Jelly Bean or higher, and have the Google app version 3.5 or higher.
And now for the code…..
<activity android:name=”.SearchableActivity”>
<intent-filter>
<action android:name=”com.google.android.gms.actions.SEARCH_ACTION”/>
<category android:name=”android.intent.category.DEFAULT”/>
</intent-filter>
</activity>
source: Android Developers