如何手动调用viewDidLoad？

Question

I'm having a slight problem with iOS. I am passing data back and forth between two view controllers using protocols and manually switching views. My problem is that when I dismiss the top view, viewDidLoad for the bottom view isn't called again. Since I'm sending information from my second view to my first view, I need viewDidLoad to be called so I can handle the information I'm passing. If you have any ideas on how to do this, any help is appreciated. Thank you.

Answer 1

- (void)viewDidLoad {
    [super viewDidLoad];
}

Is called exactly once, when the view controller is first loaded into memory. This is where you want to instantiate any instance variables and build any views that live for the entire lifecycle of this view controller.

- (void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];
}

Is called when the view is actually visible, and can be called multiple times during the lifecycle of a View Controller (example when a Modal View Controller is dismissed and the view becomes visible again)

Answer 2

使用-(void)viewDidAppear:(BOOL)animated而不是viewDidLoad

Answer 3

I am passing data back and forth between two view controllers using protocols and manually switching views. My problem is that when I dismiss the top view, viewDidLoad for the bottom view isn't called again. Since I'm sending information from my second view to my first view, I need viewDidLoad to be called

No you don't, and the fact that you think you do makes me think something else may be going wrong here.

Consider this: if you are truly passing data back from the second view controller from the first, then the first view controller has the data and can update itself now . It exists, and it has a view. So it should update itself on the spot, as you hand it the data. Then, when you dismiss the second view controller, the first view controller's view will appear - already updated. In effect, dismissing the second view controller merely reveals the first view controller's view, which was there all along, and was updated even though it wasn't showing.