从一个类调用委托的方法，而不是从具有相同结构的另一个类调用

Question

我有三门课。 AlertDetailsVC、UtilizationDetailsVC 和 SelectIOVC。

UtilizationDetailsVC 本质上是AlertDetailsVC 的一个副本，只是做了一些小的修改。

当用户为我的AlertDetailsVC 打开Scene 时，他可以按下Table 中名为Applies To 的按钮。当他按下这个Applies To按钮时，程序然后Segues到一个新的Scene，它使用SelectIOVC；然后它将该场景的Delegate 设置为等于AlertDetailsVC 中定义的Delegate。

然后当用户在Navigation Bar上点击DoneSelectIOIOVCScene;然后SelectIOVC 类将用户选择的一些数据和信息返回给AlertDetailsVC。

此流程类似地复制到UtilizationDetailsVC。

我在应该被调用的方法中添加了几行 NSLog(@"%s",__PRETTY_FUNCTION__);。

现在；当我在我的AlertDetailsVC 中点击Done 时，方法被正确调用，程序Segues 从SelectIOVC 返回到我的AlertDetailsVC 并更新用户输入的该页面上的信息。

但是我的问题是；当我在UtilizationDetailsVC 页面上做同样的事情时；并按下它的Done 按钮；程序不Segue返回。

我不确定；我的日志显示在AlertDetailsVC 的情况下调用了第一个SelectIOVCDidSave；但它从未被UtilizationDetailsVC 调用过。

相关代码：

利用：

`UtilizationDetailsVC.h`:

@class UtilizationDetailVC;

@protocol UtilizationDetailsVCDelegate <NSObject>

- (void)utilizationDetailsVCDidCancel: (UtilizationDetailVC *)controller;
- (void)utilizationDetailsVCDidDelete: (UtilizationDetailVC *)controller;
- (void)utilizationDetailsVCDidSave: (UtilizationDetailVC *)controller;

@end

@interface UtilizationDetailVC : UITableViewController <UITextFieldDelegate, UIActionSheetDelegate, SelectTimeVCDelegate, SelectDaysVCDelegate, SelectIOVCDelegate, SelectIODetailsVCDelegate, SelectTimeLengthVCDelegate, MessageVCDelegate, UtilizationContactsVCDelegate, SelectDateVCDelegate>

@property (weak, nonatomic) IBOutlet UIBarButtonItem *doneButton;
@property (strong, nonatomic) NCUtilization *utilization;
@property (weak, nonatomic) id <UtilizationDetailsVCDelegate> delegate;
@property (strong, nonatomic) NSString *identifier;
@property (strong, nonatomic) NSIndexPath *indexPath;

@property (strong, nonatomic) IBOutlet UITableViewCell *cellEnabled;
@property (strong, nonatomic) IBOutlet UITextField *titleField;
@property (strong, nonatomic) IBOutlet UITextField *descriptionField;
@property (strong, nonatomic) IBOutlet UILabel *startTimeField;
@property (strong, nonatomic) IBOutlet UILabel *endTimeField;
@property (strong, nonatomic) IBOutlet UISwitch *allDayField;
@property (strong, nonatomic) IBOutlet UILabel *daysField;
@property (strong, nonatomic) NSArray *days;
@property (strong, nonatomic) IBOutlet UILabel *appliesToField;
@property (strong, nonatomic) IBOutlet UILabel *notifyWhenField;
@property (strong, nonatomic) IBOutlet UILabel *changeExistsForField;
@property (strong, nonatomic) IBOutlet UILabel *contactsField;
@property (strong, nonatomic) NSArray *contactUUIDs;
@property (strong, nonatomic) IBOutlet UILabel *messageField;
@property (strong, nonatomic) IBOutlet UILabel *startDateField;
@property (strong, nonatomic) NSDate *startDate;
@property (strong, nonatomic) IBOutlet UILabel *endDateField;
@property (strong, nonatomic) NSDate *endDate;


- (IBAction)cancel:(id)sender;
- (IBAction)done:(id)sender;

@end

UtilizationDetailsVC.m相关方法：

- (void)selectIOVCDidCancel:(SelectIOVC *)controller
{
     NSLog(@"%s",__PRETTY_FUNCTION__);
    [self.navigationController popViewControllerAnimated:YES];
}

- (void)selectIOVCDidSave:(SelectIOVC *)controller
{
     NSLog(@"%s",__PRETTY_FUNCTION__);
    // Update input/output information with user selection on UI.
    self.appliesToField.text = controller.ioDescription;
    self.notifyWhenField.text = @"";
    [self.navigationController popViewControllerAnimated:YES];
}

警报：

AlertDetailsVC.h：

#import <UIKit/UIKit.h>
#import "NCAlert.h"
#import "SelectTimeVC.h"
#import "SelectDaysVC.h"
#import "SelectIOVC.h"
#import "SelectIODetailsVC.h"
#import "SelectTimeLengthVC.h"
#import "MessageVC.h"
#import "AlertContactsVC.h"

@class AlertDetailsVC;

@protocol AlertDetailsVCDelegate <NSObject>

- (void)alertDetailsVCDidCancel: (AlertDetailsVC *)controller;
- (void)alertDetailsVCDidDelete: (AlertDetailsVC *)controller;
- (void)alertDetailsVCDidSave: (AlertDetailsVC *)controller;

@end

@interface AlertDetailsVC : UITableViewController <UITextFieldDelegate, UIActionSheetDelegate, SelectTimeVCDelegate, SelectDaysVCDelegate, SelectIOVCDelegate, SelectIODetailsVCDelegate, SelectTimeLengthVCDelegate, MessageVCDelegate, AlertContactsVCDelegate>

@property (weak, nonatomic) IBOutlet UIBarButtonItem *doneButton;
@property (strong, nonatomic) NCAlert *alert;
@property (weak, nonatomic) id <AlertDetailsVCDelegate> delegate;
@property (strong, nonatomic) NSString *identifier;
@property (strong, nonatomic) NSIndexPath *indexPath;

@property (strong, nonatomic) IBOutlet UITableViewCell *cellEnabled;
@property (strong, nonatomic) IBOutlet UITextField *titleField;
@property (strong, nonatomic) IBOutlet UITextField *descriptionField;
@property (strong, nonatomic) IBOutlet UILabel *startTimeField;
@property (strong, nonatomic) IBOutlet UILabel *endTimeField;
@property (strong, nonatomic) IBOutlet UISwitch *allDayField;
@property (strong, nonatomic) IBOutlet UILabel *daysField;
@property (strong, nonatomic) NSArray *days;
@property (strong, nonatomic) IBOutlet UILabel *appliesToField;
@property (strong, nonatomic) IBOutlet UILabel *notifyWhenField;
@property (strong, nonatomic) IBOutlet UILabel *changeExistsForField;
@property (strong, nonatomic) IBOutlet UISwitch *localAlertField;
@property (strong, nonatomic) IBOutlet UISwitch *localAlertAudioField;
@property (strong, nonatomic) IBOutlet UILabel *contactsField;
@property (strong, nonatomic) NSArray *contactUUIDs;
@property (strong, nonatomic) IBOutlet UILabel *messageField;

- (IBAction)cancel:(id)sender;
- (IBAction)done:(id)sender;

@end

AlertDetailsVC.m 相关方法：

    - (void)selectIOVCDidCancel:(SelectIOVC *)controller
{
     NSLog(@"%s",__PRETTY_FUNCTION__);
    [self.navigationController popViewControllerAnimated:YES];
}

- (void)selectIOVCDidSave:(SelectIOVC *)controller
{
     NSLog(@"%s",__PRETTY_FUNCTION__);
    // Update input/output information with user selection on UI.
    self.appliesToField.text = controller.ioDescription;
    self.notifyWhenField.text = @"";
    [self.navigationController popViewControllerAnimated:YES];
}

选择IOVC：

选择IOVC.h

#import <UIKit/UIKit.h>

@class SelectIOVC;

@protocol SelectIOVCDelegate <NSObject>

- (void)selectIOVCDidCancel: (SelectIOVC *)controller;
- (void)selectIOVCDidSave: (SelectIOVC *)controller;

@end

@interface SelectIOVC : UITableViewController <UIPickerViewDelegate, UIPickerViewDataSource> {
    NSArray *selectIOType;
    NSArray *selectIO;
}

@property (weak, nonatomic) IBOutlet UIBarButtonItem *doneButton;

@property (weak, nonatomic) id <SelectIOVCDelegate> delegate;
@property (weak, nonatomic) NSString *identifier;
@property (strong, nonatomic) IBOutlet UIPickerView *picker;
@property (assign, nonatomic) NSUInteger type;
@property (assign, nonatomic) NSUInteger io;
@property (assign, nonatomic) NSUInteger number;
@property (strong, nonatomic) NSString *ioDescription;

- (IBAction)cancel:(id)sender;
- (IBAction)done:(id)sender;

@end

SelectIOVC.m相关方法：

- (IBAction)cancel:(id)sender
{

    [self.delegate selectIOVCDidCancel:self];
     NSLog(@"%s",__PRETTY_FUNCTION__);
}

- (IBAction)done:(id)sender
{
     NSLog(@"%s",__PRETTY_FUNCTION__);

    NSString *typeDescription = [selectIOType objectAtIndex:self.type];
    NSString *ioDescription = [selectIO objectAtIndex:self.io];
    self.ioDescription = [NSString stringWithFormat:@"%@ %@ %01d", typeDescription, ioDescription, self.number];
    [self.delegate selectIOVCDidSave:self];
}

- (void)viewDidUnload {
    [self setDoneButton:nil];
    [super viewDidUnload];
}

Answer 1

我解决了这个问题；我在UtilizationDetailsVC 和AlertDetailsVC 中都使用了一种名为- (BOOL)shouldPerformSegueWithIdentifier:(NSString *)identifier sender:(id)sender 的方法。

但是；我的错误是我从未在UtilizationDetailsVC 的Scene 和SelectIOVC Scene 之间为Segue 设置Segue Identifier。

根据我正在检查的Identifier 将值设置为我解决了我的问题。