如何使用 uinavigationcontroller 将数据和响应从第二个视图控制器发送回第一个视图控制器

Question

我的问题是如何使用 uinavigationcontroller 将数据从第二个视图控制器发送回第一个视图控制器。 我在导航控制器上有 2 个按钮来发送数据或取消，如 2ndviewcontroller.h 包含 //------------------------------------------------ ------

@class DetailsViewController;
@protocol DetailsViewControllerDelegate <NSObject>
- (void)detailsViewControllerDidCancel:(DetailsViewController *)controller;
- (void)detailsViewControllerDidSave:(DetailsViewController *)controller;
@end



@interface DetailsViewController : UIViewController
{


    UITextField *nameTextField;
    UITextField *versionTextField;
    UITextField *companyTextField;
}



@property (nonatomic, weak) id <DetailsViewControllerDelegate> delegate;

- (void)cancel:(id)sender;
- (void)save:(id)sender;
//-------------------------------------------------------------

2ndviewcontroller.m contains
- (void)cancel:(id)sender
{ 
    [self.delegate detailsViewControllerDidCancel:self];   
}


- (void)save:(id)sender
{
    [self.delegate detailsViewControllerDidSave:self];
}

虽然我的 1stviewcontroller 将 2ndviewcontroller 的委托实现为， //------------------------------------------------ ----

- (void)detailsViewControllerDidCancel:(DetailsViewController *)controller
{
    [detailedViewController dismissViewControllerAnimated:YES completion:nil];
}

- (void)detailsViewControllerDidSave:(DetailsViewController *)controller
{
    detailedViewController = [self.navigationController viewControllers][0];

    [self dismissViewControllerAnimated:YES completion:nil];

}

//--------------------------------------------- ---------

有什么想法吗？ 我正在以编程方式完成所有事情，而不是使用任何故事板。

Answer 1

您需要了解作为参数从 detail-view-controller 传递到 parent-view-controller 的数据。在委托中提及值字符串或数据数组任何内容，然后在父项中您将得到它。

首先，当您从 Detail-View-Controller 调用委托时。我添加了对选择器的响应，以避免当委托是可选的且未在父类中声明时崩溃。

- (void)save:(id)sender
{
    if (self.delegate && [self.delegate respondsToSelector:@selector(detailsViewControllerDidSave:version:company:)]) {
        [self.delegate detailsViewControllerDidSave:nameTextField.text version:versionTextfield.text company:companyTextfield.text];
    }
}


- (void)cancel:(id)sender
{
    if (self.delegate && [self.delegate respondsToSelector:@selector(detailsViewControllerDidCancel)]) {
        [self.delegate detailsViewControllerDidCancel];
    }
}

Parent-View-Controller 中的第二个，不需要传递整个 UIViewController 本身。仅传递必要的值，在您的情况下，我假设名称、版本和公司。

- (void)detailsViewControllerDidCancel
{
    // No data required/// and just dissmisses the screen
    [self dismissViewControllerAnimated:YES completion:nil];
}

- (void)detailsViewControllerDidSave:(NSString *)name version:(NSString*)version company:(NSString*)company
{

    // you can use the values as parameter.. name, version, company
    // ......

    [self dismissViewControllerAnimated:YES completion:nil];

}

示例代码：

1. How do I set up a simple delegate to communicate between two view controllers?

如果您想以数组形式发送，请执行以下操作，

父视图控制器 - (void)detailsViewControllerDidSave:(NSMutableArray*)listOfValues {

    // you can use the list of values 
    // ......

    [self dismissViewControllerAnimated:YES completion:nil];

}

细节视图控制器

- (void)save:(id)sender
{
    if (self.delegate && [self.delegate respondsToSelector:@selector(detailsViewControllerDidSave:)]) {
        [self.delegate detailsViewControllerDidSave:[NSMutableArray arrayWithObjects:nameTextfield.text, versionTextfield.text, companyTextfield.text, nil]];
    }
}

更改协议的声明，

@protocol DetailsViewControllerDelegate <NSObject>
- (void)detailsViewControllerDidCancel;
- (void)detailsViewControllerDidSave:(NSMutableArray *)listOfValues;
@end