VC被關閉時如何呼叫代表？

Question

我有兩個VC。 當第二個VC被關閉時，我需要調用委托函數。

在我的第一個VC或主VC中，我在.h文件中給出了以下代碼。

@interface FirstVC : ....<SecondVCDelegate>
-(void)didDismissViewController:(UIViewController*)vc;

但是由於某種原因，未檢測到SecondVCDelegate。

在首先介紹第二VC的同時，我給出了第一VC的.m文件。

SecondVC *optionsVC = [self.storyboard instantiateViewControllerWithIdentifier:@"SecondVC"];
optionsVC.delegate = self;
optionsVC.view.backgroundColor = [UIColor blackColor];
optionsVC.modalPresentationStyle = UIModalPresentationOverFullScreen;
[self presentViewController:optionsVC animated:YES completion:^{}];

在第二個VC .h文件中

@protocol SecondVCDelegate <NSObject>
 - (void)didDismissViewController:(UIViewController*)vc;
@end

@interface SecondVC : ...
 @property (nonatomic) id<SecondVCDelegate> delegate;
@end

在第二個VC .m文件中，我已使用以下代碼關閉了

 [self dismissViewControllerAnimated:YES completion:nil];

您能否指出我做錯了什么可能的解釋。 提前致謝。

Answer 1

這是xcode 9上的工作代碼：

ViewController.m：

#import "ViewController.h"
#import "SecondViewController.h"
@interface ViewController () <SecondVCDelegate>

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (IBAction)action:(id)sender {
    SecondViewController *optionsVC = [self.storyboard instantiateViewControllerWithIdentifier:@"SecondViewController"];
    optionsVC.delegate = self;
    optionsVC.view.backgroundColor = [UIColor blackColor];
    optionsVC.modalPresentationStyle = UIModalPresentationOverFullScreen;
    [self presentViewController:optionsVC animated:YES completion:nil];
}

-(void) didDismissViewController:(UIViewController *)vc{
    NSLog(@"working controller : %@", vc);
}
@end

SecondViewController.h：

#import <UIKit/UIKit.h>

@protocol SecondVCDelegate <NSObject>
- (void)didDismissViewController:(UIViewController*)vc;
@end

@interface SecondViewController : UIViewController
 @property (weak, nonatomic) id<SecondVCDelegate> delegate;
@end

SecondViewController.m：

#import "SecondViewController.h"

@interface SecondViewController ()

@end

@implementation SecondViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (IBAction)didmissAction:(id)sender {
    [self dismissViewControllerAnimated:true completion:^{
        [_delegate didDismissViewController:self];
    }];
}

@end

Answer 2

在您的第二個VC .m上這樣做

下面實現的第一個綜合代表

@synthesize delegate;

之后在viewController上使用它關閉：

[self dismissViewControllerAnimated:YES completion:^{

    [self.delegate didDismissViewController: self];
}];