如何使app 直接關掉,不在進入後臺

UIApplicationExitsOnSuspend (Boolean - iOS) specifies that the application should be terminated rather than moved to the background when it is quit. Applications linked against iPhone SDK 4.0 or later can include this key and set its value to YES to prevent being automatically opted-in to background execution and application suspension. When the value of this key is YES, the application is terminated and purged from memory instead of moved to the background. If this key is not present, or is set to NO, the application moves to the background as usual.