I am soon going on a field trip and would like to give my friends the ability to use the flash light from the phone without giving them the pattern to unlock the phone. Is that possible to add the flashlight/torch to the locked screen just like the camera?
I have a Galaxy S5 with Android 4.4.2
Make sure your camera shortcut is on in the lockscreen. Open the camera from the lockscreen, drag your flash setting to the top from the camera settings and make sure it is on. Now all you have to do is open the camera shortcut and click video and your light will stay on. It will also record video while it's on but this is the only way to turn on your flashlight from the lockscreen.
Not without a different ROM but you may be able to add one to the notification area. Try this, I don't know how well (if at all) it works on the S5 but it's worth a shot.
On the last models of Samsung was easy! Just press the volume key and the flashlight is turning on! (of course you should first to approve this in settings:) When you want to stop it just press the volume down! I have Xcover 1 and 2, I used it a lot, it is easy and good option but sometimes the flashlight was turned on in my pocket of my carhartt jeans and the battery finished very quick. So in settings you can make the flashlight to work only 1-2min. and to stop automatically. I bought S5 Active few days ago and I am very angry that the phone has no same option!!! I see one decision but. To upload a Torch APP and then to switch on this APP with functional extra key, which is over the volume key.
The S5 Lollipop update now has the flashlight available as a notification sort cut, you can add it to the list of 'quick settings' and just use it that way now. Tested as of today 25.02.2015.0
You can try CM Locker by Cheetah Mobile. This is an iOS based Locker. Give CM Locker a try!
Turn on the flashlight by holding both volume keys with Torchie - Volume Button Torch app.
Or shake your phone to turn on the flashlight with Shake Flashlight app.
Source: 5 Quick Ways to Turn on the Flashlight on Your Android Device