Is it possible to switch between WiFi networks in an iPhone App programmatically? At time of app execution if one network goes down but that is still connected and I want to switch to another wi-fi network. Is this possible?
There is no iOS API for this, but there can be some possible solutions, like make it available on Cydia for jailbroken devices. AirServer just did this.
Your iPhone app shouldn't manage wifi networks. If it does, it won't get approved by Apple to be put in the App Store. The iPhone itself manages wifi connections, not a third-party app.
If you are developing for a jailbroken iphone, you can develop a MobileSubstrate extension/ Tweak with Theos and hook into the SpringBoard Application. The SBWiFiManager interface is part of SpringBoard app and has a lot of useful methods that should help you with controlling WiFi.
来源：https://stackoverflow.com/questions/8776241/how-to-switch-between-wi-fi-networks-at-runtime-programmatically-in-iphone-app