viewDidLoad is called only the first time

问题

Maybe someone could tell me why when launch my app in the second time (after pressing the home button) the method viewDidLoad: is not being called?

回答1:

On iOS 4 apps are no longer exited when pressing the home button. They are moved out of RAM, paused and then continued when you re-enter them, not launched again.

回答2:

In iOS4 there is:

• (void)applicationDidBecomeActive:(UIApplication *)application { }

Which is called when the application becomes active (out of background) you could call things from here that need to happen when you open the app.

Thanks James

回答3:

The second time you "launch" your application, in fact you are not launching but only re-activating (your application was in background). Your views are not reloaded.

As said in the previous answers :

• You can detect it via (void)applicationDidBecomeActive:(UIApplication *)application and execute some code here (refresh HMI, refetch datas, etc...),
• Or move your code to viewWillAppear

来源：https://stackoverflow.com/questions/3586416/viewdidload-is-called-only-the-first-time