App Delegate life Cycle Methods

• application:willFinishLaunchingWithOptions:—This method is your app’s first chance to execute code at launch time.
  
• application:didFinishLaunchingWithOptions:—This method allows you to perform any final initialization before your app is displayed to the user.
  
• applicationDidBecomeActive:—Lets your app know that it is about to become the foreground app. Use this method for any last minute preparation.
  
• applicationWillResignActive:—Lets you know that your app is transitioning away from being the foreground app. Use this method to put your app into a quiescent state.
  
• applicationDidEnterBackground:—Lets you know that your app is now running in the background and may be suspended at any time.
  
• applicationWillEnterForeground:—Lets you know that your app is moving out of the background and back into the foreground, but that it is not yet active.
  
• applicationWillTerminate:—Lets you know that your app is being terminated. This method is not called if your app is suspended.