Want to quickly turn WiFi, Bluetooth, or the flashlight on or off on your Android phone? You can pull down from the top of the screen to bring up the Quick Settings panel and tap an icon to toggle the feature.
Or if you have a device running Android 5.0 and have the latest version of the Google Search app installed, you can use voice commands to do the same thing without even touching your phone.
Just tap the microphone icon or say “OK Google” if hotword detection is enabled, and then say “turn on WiFi,” “turn off WiFi,” or try Bluetooth or Flashlight.
Each one should enable or disable the appropriate feature on your phone — and give you visual and verbal confirmation by telling you that the feature’s been turned on or off along with showing a Google Now card.
Android Police notes that you can even use voice commands to toggle the flashlight on phones where device makers have removed the toggle from the Quick Settings panel.
Little Flashlight for Android – https://play.google.com/store/apps/details?id=com.pw.megaflashlight
Neat app. Unfortunately, Android 5.0 took away the ability for apps like this, Tasker, Llama, etc. to turn on/off mobile data unless you root your phone (even on Nexus devices). There are two issue trackers for this “bug”. Star them to help raise the issue to Google to provide a sanctioned method to restore the ability and stop removing useful functionality.
https://code.google.com/p/android/issues/detail?id=130608
https://code.google.com/p/android/issues/detail?id=78084