模拟按Home键退出应用的简单方法(分享)

实例如下：

func exitApplication() {
   let app = UIApplication.sharedApplication().delegate as! AppDelegate
   let window = app.window
   dispatch_async(dispatch_get_main_queue(), {
     UIView.animateWithDuration(0.5, animations: {
       window!.alpha = 0
       window?.frame = CGRectMake((window?.bounds.size.width)!/2.0, (window?.bounds.size.height)!/2.0, 0, 0)
     }) { (finish) in
       exit(0)
     }
   })
 }