ios - 需要有关在 UINavigationcontroller 中将数据从 child 传递给 parent 的帮助

Question

在 UINavigationController 中这是子 Controller

.h

@protocol childProtocol <NSObject>

-(void)childMethod:(NSArray*)params;

@end

@property (strong, nonatomic) id<childProtocol>childDelegate;

@property (weak, nonatomic) parentVC *pVC;

---

.m 

if([self.childDelegate respondsToSelector:@selector(childMethod:)]) {

    [self.childDelegate performSelector:@selector(childMethod:) withObject:self.arry];    

}

这是我的父 Controller

.m

-(void)childMethod:(NSArray *)params {
    // some work 
}

...

 childVC *cVC = [[childVC alloc]init];
    cVC.pVC = self;

但是 childMethod: 没有被调用所以我在互联网上搜索并得到了这篇文章 UINavigationControllers: How to pass value to higher (parent?) controller in stack?

我试图创建一个弱引用，但不知道如何使用它来让委托(delegate)将数据从子对象传递到父对象？

Answer 1

试试这个。检查附件中的示例项目

ParentViewController.h

#import <UIKit/UIKit.h>

@interface ParentViewController : UIViewController

- (void)passData:(NSString *)strText;

@end

ParentViewController.m

- (IBAction)btnGoToSecondView:(id)sender {
    ChildViewController *secondVC = [[ChildViewController alloc] initWithNibName:@"ChildViewController" bundle:nil];
    secondVC.delegate = self;
    [self presentViewController:secondVC animated:YES completion:nil];

}

- (void)passData:(NSString *)strText {
    NSLog(@"Data Passed = %@",strText);
}

ChildViewController.h

#import <UIKit/UIKit.h>
#import "ParentViewController.h"

@class ParentViewController;

@interface ChildViewController : UIViewController

@property(nonatomic, assign) ParentViewController *delegate;

@end

ChildViewController.m

- (IBAction)btnPassDataBack:(id)sender {
    if([self.delegate respondsToSelector:@selector(passData:)]) {
        [self.delegate passData:@"Hello"];
    }
    [self dismissViewControllerAnimated:YES completion:nil];
}

Sample Project