为什么有时会首先调用viewDidLoad，有时它被称为后者？

Question

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

在一个UIViewController中，这里是序列

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

因为在viewDidLoad中调用了通知设置，所以我需要在`

之前先调用viewDidLoad
1. -(void) tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController

`

我怎么能实现这个目标？

[[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（）

中