title: Application event when screen becomes active
body: <p>I have a NSTimer that I create when entering method <code>- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions</code>.</p>
  
  <p>When entering method <code>- (void)applicationDidEnterBackground:(UIApplication *)application</code> I say <code>[timer invalidate]; timer = nil;</code></p>
  
  <p>When entering method <code>- (void)applicationWillEnterForeground:(UIApplication *)application</code> I create the timer again. This works when the user has pressed the home button and then runs the application again.
  However if my screen gets inactive because of user inactivity when inside the app, then becomes active and then automatically enters the application again, the timer will not work.
  Therefore I am wondering what method is accessed when the application re-enters from an inactive screen.</p>
  
  <p>Thank you</p>