I frequently get emails about this question, even though it’s covered in the FAQ. I’ll try to give a more detailed explanation than the FAQ provides. From the FAQ:
Q: The GPS doesn’t turn on or off, even though I have those options enabled in the settings.
A: The GPS on/off function is considered experimental, and is not guaranteed to work on all devices. Android normally doesn’t allow apps to turn the GPS on/off, but UWW uses a hack that works on some devices. If you have a device running Android 2.3 or above, it’s likely that this function won’t work for you. However, it may work if you’re running a custom ROM like CyanogenMod.
In Android 1.0, apps were able to turn the GPS on or off. In Android 1.6, Google decided that apps shouldn’t be able to do this anymore. Why they decided to do this is beyond me. Apps can turn WiFi and Bluetooth on and off – why not GPS? Apparently Google thinks that the GPS poses some privacy risk to the user. OK, perhaps a malicious app could turn on the GPS and then track the user’s location. That would be bad, but to keep things in perspective, if you have a malicious app on your phone, it could do far worse things than track your location. Google provides an API for completely erasing all the data on the phone. Surely this is a bigger risk than toggling the GPS. Come on, Google, why not let users decide for themselves if they want to allow an app to toggle the GPS? OK, that’s the end of my little rant.
If Google disabled GPS toggling in Android 1.6, how does Unlock With WiFi toggle the GPS? Well, there is a bug in Android 1.6 to 2.2 that allows apps to toggle the GPS via manipulation of the Power Control widget that comes with Android. It’s a well known bug, and many Android apps use it to toggle the GPS. Such apps include automation apps like Locale and Tasker, and third party power control widgets as well.
In Android 2.3, Google fixed this bug. Does that mean that Unlock With WiFi can’t toggle the GPS in Android 2.3 and above? The answer is maybe. In a stock 2.3 ROM, UWW probably can’t toggle the GPS. However, many custom ROMs, like CyanogenMod, still include the old, buggy version of the Power Control widget. This is deliberately done to enable apps to toggle the GPS. So UWW might be able to toggle the GPS in Android 2.3+, if you have a custom ROM. If you’re on stock Android 2.3+, then I’m sorry, there’s nothing I can do.