Wi-Fi Auto Toggle is an Android application that turns Wi-Fi on when you enter a location in which you have used Wi-Fi and turns it off when you leave.
All you have to do is turn on Wi-Fi and connect to the network with Wi-Fi Auto Toggle running.
In order to save battery Wi-Fi Auto Toggle doesn't turn on Wi-Fi to find out the phone location. Instead it solely relies on cellular network.
Use of wireless networks must be enabled in Home -> Menu -> Settings -> Location & security -> Use wireless networks.
Unless GPS is used, which drains battery, the accuracy of location provided by cellular network is very coarse.
Wi-Fi Auto Toggle works at its best when the Wi-Fi locations are relatively far apart.
In some rare cases the location provided by cellular network was quite different than location provided by Wi-Fi.
Wi-Fi Auto Toggle would not work for such locations.
When the screen goes to sleep, the phone checks it's location every four minutes, so Wi-Fi may not be turned on/off instantly.
When no application needs current location, GPS is not tuned on, even when it is enabled.
Since Wi-Fi Auto Toggle needs current location, the operating system will use GPS, when it is enabled, even when the phone is asleep.
In order to conserve battery GPS should be disabled when Wi-Fi Auto Toggle is used.