On iOS 7.0 and below, SBFrontmostApplicationDisplayIdentifier from the Springboard framework specified the app running in the foreground, but that capability has been blocked (considered as a vulnerability, see the Common Vulnerabilities and Exposures page dedicated to it here) in iOS 8.
Does anyone have an iOS 8 alternative for this?
It is not possible to do it on iOS 8 since a vulnerability was discovered. More info here: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-4361
来源：https://stackoverflow.com/questions/26161001/ios-8-how-to-determine-the-foreground-app-as-well-as-get-list-of-running-apps