objective-c - 为什么有时先调用 viewDidLoad 有时调用后者？

Question

-(void) tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
{
    [[NSNotificationCenter defaultCenter] postNotificationName:ListOrMapAddReloadButton object:self]; //Add nearby buttons
}

其中一个UIViewController是顺序

1. viewDidload被叫
2. [[NSNotificationCenter defaultCenter] postNotificationName:ListOrMapAddReloadButton object:self];

而且因为通知设置是在 viewDidLoad 调用的，所以我需要先调用 viewDidLoad `

1. -(void) tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController

`

我怎么能做到这一点？

[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(addReloadButton) name:ListOrMapAddReloadButton object:nil];
[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(addNearbyButton) name:ListOrMapAddNearbyButton object:nil];

Answer 1

将您的通知放在 ViewWillAppear ()