Objective c 通过viewcontroller将代理传递给viewcontroller

我的故事板中有三个viewController，每个都有三个viewController类。在我的主viewController中，我以“模态”类型segue打开导航viewController，这是一种多步骤形式，其中有两个视图。当用户在最后一个（第二个）视图中点击“Finish”时，模式被取消，用户返回主屏幕

我正在与代表们一起这样做。finish按钮的代码也在代理中，并放置在主viewController的实现文件中。为了实现这一点，我将委托从主视图传递到导航的第一个视图，然后在单击“下一步”时从第一个视图传递到第二个（最后一个）视图（具有“完成”按钮）

将委托从main传递到navigation的第一页如下所示：

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"CreateCast"])
    {
        UINavigationController *navigationController = segue.destinationViewController;
        CreateCastStepOneVC *createCastStepOneVC = [[navigationController viewControllers] objectAtIndex:0];
        createCastStepOneVC.delegate = self;
    }
}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"ToCastStepTwo"])
    {
        CreateCastStepTwoVC *createCastStepTwoVC = 
        segue.destinationViewController;
        createCastStepTwoVC.delegate = delegate;
    }
}

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

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

@property (nonatomic, __unsafe_unretained) id<MyProtocol> delegate;

代理从导航的第一个视图传递到第二个视图如下：

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"CreateCast"])
    {
        UINavigationController *navigationController = segue.destinationViewController;
        CreateCastStepOneVC *createCastStepOneVC = [[navigationController viewControllers] objectAtIndex:0];
        createCastStepOneVC.delegate = self;
    }
}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"ToCastStepTwo"])
    {
        CreateCastStepTwoVC *createCastStepTwoVC = 
        segue.destinationViewController;
        createCastStepTwoVC.delegate = delegate;
    }
}

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

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

@property (nonatomic, __unsafe_unretained) id<MyProtocol> delegate;

事情做得很好，代表正在按要求完成其工作。但一个令人担忧的警告突然出现：

正在将“\u弱id”传递给的参数 不兼容的类型“id”

第一个导航视图中的属性声明如下所示：

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"CreateCast"])
    {
        UINavigationController *navigationController = segue.destinationViewController;
        CreateCastStepOneVC *createCastStepOneVC = [[navigationController viewControllers] objectAtIndex:0];
        createCastStepOneVC.delegate = self;
    }
}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"ToCastStepTwo"])
    {
        CreateCastStepTwoVC *createCastStepTwoVC = 
        segue.destinationViewController;
        createCastStepTwoVC.delegate = delegate;
    }
}

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

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

@property (nonatomic, __unsafe_unretained) id<MyProtocol> delegate;

@属性（非原子，弱）id委托；

属性声明是第二个导航视图，如下所示：

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"CreateCast"])
    {
        UINavigationController *navigationController = segue.destinationViewController;
        CreateCastStepOneVC *createCastStepOneVC = [[navigationController viewControllers] objectAtIndex:0];
        createCastStepOneVC.delegate = self;
    }
}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"ToCastStepTwo"])
    {
        CreateCastStepTwoVC *createCastStepTwoVC = 
        segue.destinationViewController;
        createCastStepTwoVC.delegate = delegate;
    }
}

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

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

@property (nonatomic, __unsafe_unretained) id<MyProtocol> delegate;

@属性（非原子，弱）id委托；

您是如何在

CreateCastStepTwoVC

上声明委托属性的？也， 您的代表是否符合您定义的协议

委托属性的典型声明如下所示：

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"CreateCast"])
    {
        UINavigationController *navigationController = segue.destinationViewController;
        CreateCastStepOneVC *createCastStepOneVC = [[navigationController viewControllers] objectAtIndex:0];
        createCastStepOneVC.delegate = self;
    }
}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"ToCastStepTwo"])
    {
        CreateCastStepTwoVC *createCastStepTwoVC = 
        segue.destinationViewController;
        createCastStepTwoVC.delegate = delegate;
    }
}

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

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

@property (nonatomic, __unsafe_unretained) id<MyProtocol> delegate;

编辑：

---

看到属性声明后，您需要根据以下问题将

weak

更改为

\u unsafe\u unrepaired

，

您是如何在

CreateCastStepTwoVC

上声明委托属性的？也， 您的代表是否符合您定义的协议

委托属性的典型声明如下所示：

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"CreateCast"])
    {
        UINavigationController *navigationController = segue.destinationViewController;
        CreateCastStepOneVC *createCastStepOneVC = [[navigationController viewControllers] objectAtIndex:0];
        createCastStepOneVC.delegate = self;
    }
}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"ToCastStepTwo"])
    {
        CreateCastStepTwoVC *createCastStepTwoVC = 
        segue.destinationViewController;
        createCastStepTwoVC.delegate = delegate;
    }
}

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

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

@property (nonatomic, __unsafe_unretained) id<MyProtocol> delegate;

编辑：

---

看到属性声明后，您需要根据以下问题将

weak

更改为

\u unsafe\u unrepaired

，

您可以子类

UINavigationController

，并在子类中添加自定义协议。使用此方法，您将能够从导航控制器中的所有视图控制器调用您的代理。例如，我过去就是这样做的：

@class CustomNavigationController;

@protocol CustomNavControllerDelegate <NSObject>

- (void)editImageController:(CustomNavControllerDelegate *)controller
didFinishPickingMediaWithInfo:(NSDictionary *)info;
- (void)editImageControllerDidCancel:(CustomNavControllerDelegate *)controller;

@end

@interface CustomNavigationController : UINavigationController

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

@end

@class CustomNavigationController；
@协议CustomNavControllerDelegate
-（无效）editImageController:（CustomNavControllerDelegate*）控制器
didFinishPickingMediaWithInfo:（NSDictionary*）信息；
-（void）editImageControllerDidCancel:（CustomNavControllerDelegate*）控制器；
@结束
@接口CustomNavigationController:UINavigationController
@属性（非原子，弱）id委托；
@结束

---

在本例中，我实现了与

UIImagePickerController

类似的功能。事实上，如果您查看选择器的声明文件，这就是它的实现方式。

您可以子类

UINavigationController

并在子类中添加自定义协议。使用此方法，您将能够从导航控制器中的所有视图控制器调用您的代理。例如，我过去就是这样做的：

@class CustomNavigationController;

@protocol CustomNavControllerDelegate <NSObject>

- (void)editImageController:(CustomNavControllerDelegate *)controller
didFinishPickingMediaWithInfo:(NSDictionary *)info;
- (void)editImageControllerDidCancel:(CustomNavControllerDelegate *)controller;

@end

@interface CustomNavigationController : UINavigationController

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

@end

@class CustomNavigationController；
@协议CustomNavControllerDelegate
-（无效）editImageController:（CustomNavControllerDelegate*）控制器
didFinishPickingMediaWithInfo:（NSDictionary*）信息；
-（void）editImageControllerDidCancel:（CustomNavControllerDelegate*）控制器；
@结束
@接口CustomNavigationController:UINavigationController
@属性（非原子，弱）id委托；
@结束

---

在本例中，我实现了与

UIImagePickerController

类似的功能。事实上，如果查看选择器的声明文件，这就是它的实现方式。

这是通过视图控制器传递委托的推荐方式吗？或者还有其他更好的方法吗？我认为没有理由不使用代理来完成这项工作。顺便说一句，我对segues的故事板没有太多的了解，所以我对那里的最佳实践并不完全熟悉。这种通过视图控制器传递代理的方法是推荐的吗？或者还有其他更好的方法吗？我认为没有理由不使用代理来完成这项工作。那就是说，我对segues的故事板工作不多，所以我对那里的最佳实践并不完全熟悉。