viewDidLoad何时被调用？ [英] When is viewDidLoad called?

问题描述

是否可以安全地假设 chatViewController 的属性，即 fetchedResultsController ，是一个子类的实例 UITableViewController ，当 viewDidLoad 被调用时，总是 nil ，假设它在 viewDidUnload 中设置为 nil ？ Phew！

Is it safe to assume that an attribute, namely fetchedResultsController, of chatViewController, an instance of a subclass of UITableViewController, is always nil when viewDidLoad is called, assuming that it's set to nil in viewDidUnload? Phew!

如果是这种情况，那么我认为没有必要像Xcode示例应用程序CoreDataBooks那样重新定义访问器函数。我宁愿把所有代码放在 viewDidLoad 而不是单独的函数中，因为这是我唯一使用它的地方。

If that's the case, then I see no immediate need to redefine the accessor function like in the Xcode example application CoreDataBooks. I'd rather just put all that code in viewDidLoad instead of in a separate function because that's the only place I'll use it.

推荐答案

加载视图后调用viewDidLoad。 fetchedResultsController是否为n取决于viewController的初始化方式。例如，在创建 detailViewController 时，可以在 viewDidLoad fetchedViewController c $ c>被调用：

viewDidLoad is called after your view is loaded. Whether or not fetchedResultsController is nil or not depends on how the viewController is initialized. For example, when creating the detailViewController, you could set its fetchedViewController before viewDidLoad is called:

RecipeDetailViewController *detailViewController = [[RecipeDetailViewController alloc] initWithStyle:UITableViewStyleGrouped];
detailViewController.fetchedResultsController = fetchedResultsController;

[self.navigationController pushViewController:detailViewController animated:animated];
[detailViewController release];

那就是说，然后在viewDidUnload中nil'ing fetchedResultsController将确保它为零。

That said, then nil'ing fetchedResultsController in viewDidUnload would ensure that it's nil.

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