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标题: ios - 无法从呈现的 View Controller 访问委托(delegate)方法 [打印本页]

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作者: 菜鸟教程小白    时间: 2022-12-11 17:10
标题: ios - 无法从呈现的 View Controller 访问委托(delegate)方法

委托(delegate)声明

// FolderListViewController.h
#import <UIKit/UIKit.h>
#import "Folder.h"

@protocol FolderSelectionDelegate <NSObject>

@required
- (void)setFolderFolder *)folder;

@end

@interface FolderListViewController : UITableViewController

@property (nonatomic, assign) id<FolderSelectionDelegate> delegate;

- (IBAction)showDashboardid)sender;

@end

从 didSelectRowAtIndexPath 调用委托(delegate):

// FolderListViewController.m
- (void)tableViewUITableView *)tableView didSelectRowAtIndexPathNSIndexPath *)indexPath {
    [self.delegate setFolder:dataSource[indexPath.row]];
}

应该接收消息的 VC

#import <UIKit/UIKit.h>
#import "FolderListViewController.h"
#import "Folder.h"

@interface ProjectListViewController : UITableViewController <FolderSelectionDelegate, UISplitViewControllerDelegate, UISearchBarDelegate, UINavigationControllerDelegate>

@property (nonatomic,retain)UIActivityIndicatorView *activityIndicatorObject;
@property (nonatomic, copy)Folder *folder;


-(void)loadProjectsFolder*)folder;

@end

呈现 VC 的 Action

- (void)foldersButtonTapped {
    UINavigationController *vc = [[UIStoryboard storyboardWithName"MainStoryboard_iPhone" bundle:nil] instantiateViewControllerWithIdentifier"FolderListNavController"];
    vc.delegate = self;
    [self presentViewController:vc animated:YES completion:nil];
}

委托(delegate)方法实现

- (void)setFolderFolder *)folder {
    _folder = folder;
    [self loadProjects:folder];
}

我已经阅读了这里的多个线程并且没有任何运气。起初，在展示 FolderListVC(即 vc.delegate = self)时，我没有提到 ProjectListVC 设置。不过，这似乎不是问题所在。我正在开发一个为 iPad 构建的应用程序，并将其扩展到所有设备上。此处的实现有效(它设置为 Split View Controller )。任何帮助将不胜感激

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Best Answer-推荐答案

我认为 UINavigationcontroller 正在制造问题，因为它没有设置 FolderListViewController 委托(delegate)。你可以这样试试吗？

 FolderListViewController *vc=[self.storyboard instantiateViewControllerWithIdentifier"FolderListViewController"];

    vc.delegate=self; // protocol listener
    [self.navigationController pushViewController:vc animated:YES];

关于ios - 无法从呈现的 View Controller 访问委托(delegate)方法，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/38769673/

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