某些代码未在从另一个ViewController调用的方法中执行 [英] Some code not executing in a method called from another ViewController

问题描述

我的问题
我有一个标准的UIViewController.按下按钮，它将加载表单模态视图控制器.按下UIBarButtonItem键消除此模式视图时，我通过执行以下操作来调用方法:

My problem
I have a standard UIViewController. With the press of a button, it loads a form sheet modal view controller. When dismissing this modal view with the press of a UIBarButtonItem I call a method by doing:

ViewController *main = [[ViewController alloc] initWithNibName:nil bundle:nil];
[main updateLabel];

在主ViewController中的方法-(void)updateLabel中，我设置了标签文本，但标签不会更改.但是我知道该函数会被调用，因为如果我执行NSLog(@"Method call test);而不是label.text = @"Test"，则可以在控制台中看到该消息.

In the method -(void)updateLabel in the main ViewController I'm setting the text of a label, but the label won't change. But I know the function gets called, because if I do a NSLog(@"Method call test); instead of label.text = @"Test" I can see the message in console.

我做错了什么?这一定是我在主ViewController中调用方法的方式，因为我可以轻松地在其他任何地方更改标签.

What am I doing wrong? It must be the way I'm calling the method in the main ViewController, because I can easily change the label anywhere else.

我要做什么:
在关闭模式视图控制器时，我希望在主视图控制器中调用一个方法，在这种情况下，请更改标签的文本.

What I want to do:
When dismissing a modal view controller, I want a method to be called in the main view controller, and in this case change the text of a label.

感谢您的帮助！

推荐答案

您正在使用该代码创建ViewController的新实例，而没有获得指向您现有实例的指针.

You're creating a new instance of ViewController with that code, not getting a pointer to the one you already have.

如果ViewController是呈现模态视图的控制器，那么您可以使用指向它的指针，

If ViewController is the controller that presented the modal view, then you can get a pointer to it with,

ViewController *main = self.presentingViewController;

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