popover segue 中无法识别的选择器

Posted 2023-03-22

【中文标题】popover segue 中无法识别的选择器

【英文标题】：unrecognized selector at popover segue

【发布时间】：2014-05-20 17:22:19

【问题描述】：

我在我的应用程序中使用此代码来传递具有相应序列的数据：

-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender 
if ([segue.identifier isEqualToString:@"readMoreDetail"]) 
    MoreViewController *destinationViewController = segue.destinationViewController;
    destinationViewController.openSubject = [self.detailItem description];
 else if ([segue.identifier isEqualToString:@"notesSegue"]) 
    NSLog(@"segue");
    NotesTableViewController *destinationViewController = segue.destinationViewController;
         destinationViewController.openSubject = [self.detailItem description];
     else 
        // Do nothing
    

我在 NavigationController 中嵌入了一个 UIViewController 并创建了一个从另一个 UIViewController 到 NavigationController 的弹出框 - 但是当我导航时出现此错误：

-[UINavigationController setOpenSubject:]: unrecognized selector sent to instance 0x15e532a0

有什么想法吗？

谢谢！

NotesTableViewController.h

#import <UIKit/UIKit.h>

@interface NotesTableViewController : UITableViewController <UINavigationControllerDelegate>

@property(nonatomic, strong)NSString *openSubject;

@end

NotesTableViewController.m

#import "NotesTableViewController.h"

@interface NotesTableViewController ()

NSMutableArray *_objects;


@end

@implementation NotesTableViewController
@synthesize openSubject;

- (id)initWithStyle:(UITableViewStyle)style

self = [super initWithStyle:style];
if (self) 
    // Custom initialization

return self;


- (void)viewDidLoad

[super viewDidLoad];

if (openSubject.length == 0) 
    // There's currently no subject open, write it in the navigationbar
    // Prompt = open subject
    // Title = notes header
    self.navigationItem.prompt = @"No subject selected";
    self.navigationItem.title = @"My Notes";
 else 
    // Open the subject

    // Prompt = notes header
    // Title = open subject
    self.navigationItem.prompt = openSubject;
    self.navigationItem.title = @"My notes";

    // Load the notes data
    // Create the key
    NSString *partOfKey = @"-notes";
    NSString *notesKey = [NSString stringWithFormat:@"%@%@", openSubject, partOfKey];

    // Load the _objects from NSUserdefaults
    _objects = [[NSUserDefaults standardUserDefaults] objectForKey:notesKey];


// Uncomment the following line to preserve selection between presentations.
// self.clearsSelectionOnViewWillAppear = NO;

// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
self.navigationItem.leftBarButtonItem = self.editButtonItem;

// Register a class or nib file using registerNib:forCellReuseIdentifier
// o registerClass:forCellReuiseIdentifier: method before calling this method
[self.tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:@"Cell"];


- (void)awakeFromNib

self.clearsSelectionOnViewWillAppear = NO;
self.preferredContentSize = CGSizeMake(320.0, 600.0);
[super awakeFromNib];


- (void)didReceiveMemoryWarning

[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.

- (IBAction)addNote:(id)sender 
// Create a new note
if (openSubject.length == 0) 
    // The openSubject is nil, can't add a subject - tell the user
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle: @"No subject" message: @"Please select a subject prior to adding a note" delegate: nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; [alert show];
 else 
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"New note" message:@"Enter a note" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"Add", nil];
    alert.alertViewStyle = UIAlertViewStylePlainTextInput;
    [alert show];



- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
// The user created a new subject, add it
if (buttonIndex == 1) 
    // Get the input text
    NSString *newNote = [[alertView textFieldAtIndex:0] text];

    // Initialize objects
    if (!_objects) 
        _objects = [[NSMutableArray alloc] init];
    
    // Check if the note already exist
    if ([_objects containsObject:newNote]) 
        // Tell the user this note already exists
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle: @"Already exists" message: @"This note already exist, sorry" delegate: nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
     else 
        // The note doesn't exist, add it
        [_objects insertObject:newNote atIndex:0];
        NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
        [self.tableView insertRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];

        // Save the new _objects
        [self saveObjects];
    



-(void)saveObjects 
// Create the key
NSString *partOfKey = @"-notes";

    // Save the new objects
NSString *notesKey = [NSString stringWithFormat:@"%@%@", openSubject, partOfKey];
[[NSUserDefaults standardUserDefaults] setObject:_objects forKey:notesKey];


#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView

#warning Potentially incomplete method implementation.
// Return the number of sections.
return 1;


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section

// Return the number of rows in the section.
return _objects.count;



- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];

NSString *object = _objects[indexPath.row];
cell.textLabel.text = [object description];
return cell;


- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath

if (editingStyle == UITableViewCellEditingStyleDelete) 
    [_objects removeObjectAtIndex:indexPath.row];
    [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];

    // Save the new objects
    [self saveObjects];
 else if (editingStyle == UITableViewCellEditingStyleInsert) 
    // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view.




/*
// Override to support conditional editing of the table view.
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath

// Return NO if you do not want the specified item to be editable.
return YES;

*/

/*
// Override to support rearranging the table view.
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath


*/

/*
// Override to support conditional rearranging of the table view.
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath

// Return NO if you do not want the item to be re-orderable.
return YES;

*/

    /*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before     navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender

// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.

*/

@end

（我相信每个人都不会窃取此代码）

【问题讨论】：

顺便说一句：*** 上的所有用户帖子均在此CC license 下获得许可。所以每个人都可以steal您发布的代码...

基本上，您在某处所称的 NotesTableViewController 不是。如果您查看异常下方的堆栈跟踪，您将被指向错误的行。

【参考方案1】：

如果您触发对UINavigationController 的转场，segue.destinationViewController 将是导航控制器，不是导航控制器中包含的视图控制器。

但是，您可以参考您的 NotesTableViewController:

UINavigationController *navController = segue.destinationViewController;
NotesTableViewController *notesTableVC = (NotesTableViewController *)[navController topViewController];

然后你就可以使用了

notesTableVC.openSubject = [self.detailItem description];

等等。在NotesTableViewController 中设置属性。

【讨论】：

现在试过了，但它说：“UINavigationController”没有可见的@interface声明了“rootViewController”的选择器

好的，该属性似乎不存在。更新了我的答案。请改用topViewController。或者 - 如果导航堆栈中有其他视图控制器 - [[navController viewControllers] objectAtIndex:0].

【参考方案2】：

确保您的 segue 标识符被正确识别为 "notesSegue" 和 "readMoreDetail" ，有时您必须清理项目并再次运行它。

【讨论】：

我已经检查过了——动作确实会触发，因为 NSLog 也会记录，但是这行被指责：destinationViewController.openSubject = [self.detailItem description];

发布您的 NotesTableViewController。你是如何初始化 openSubject 的？ @user3653447

@user3653447 看起来不错。好奇“[self.detailItem description]”是否返回不是字符串的东西，这会导致无法识别的选择器错误。尝试 NSLog "[self.detailItem description]"

NSLog 记录一个字符串，就像它应该做的那样:)

很高兴知道您找到了答案@user3653447