我可以在viewDidLoad之外的故事板中初始化iPhone应用程序中的内容吗？

Question

I have an iPhone application which consists of two View Controllers; a main one, and one with the help screen. Each one has a button that performs the segue from one to the other.

The problem I have is, when I segue back from the help screen to the main screen, the main view controller's viewDidLoad method gets called, so all of the initialization I did when the app was first started is repeated. Is there another method in the view controller that gets called just once, where I can do the initialization?

My first thought was, "Have a boolean variable that is initially set to false, then have viewDidLoad test it, and if it is false, do the initialization, then set it to true" - but how do I initialize it to false in the first place?

Answer 1

My guess is that you're doing a "Push" segue (which is the most standard kind of segue one can do in an iOS app), and if you are using a "Push" segue that means you have a navigation controller in your app.

The best thing to do here is not to push another "Main" view controller onto the stack of other view controllers (which is why you are seeing " viewDidLoad " called each time you push the main view), but instead when you click a "go to main" button in your help screen, pop the help screen off and return to the previous one. The call that would do this is UINavigationController's popViewControllerAnimated method.

Doing that means " viewDidLoad " on that view controller only gets called once, as the main view gets loaded once.

Answer 2

on the .m class file create a bool on @implementaition :

@implementation yourClass{

    bool initialize = 0;
}

and then test it on view did load:

-(void)viewDidLoad{

    if(initialize == 0){

    //do everything you need to do

    initialize = 1;

    }
}

I think it will work...