Google have updated their Google Search app which brings with it new voice search features from any screen.
As you will already know, the “OK Google” hotword detection in Android will currently work from the home screen, but not if you are in an application already. The new update, Google Search 3.5.14 which will be rolling out soon, changes this by adding options to turn on “Ok Google” from any screen.
New toggles in the app’s settings will allow you to use hotword detection from the lock screen and even when using other applications. Other updates include a new Audio History feature which is basically a search history based on your spoken commands so that future searches can be made more accurately.
Google Search 3.5.14 hasn’t been officially released yet, but download links to the apk have already been posted on Phandroid.