方法不叫

我得到的下一個問題，我有3次（一個UITableView，AND2視圖控制器）我提出的下一個2層的協議：AddViewControllerDelegate和ViewAlarmControllerDelegate： AddViewController.h：方法不叫

@protocol AddViewControllerDelegate <NSObject> 

- (void)addAlarm:(AlarmObject *)alarm; 

@end 

@interface AddViewController : UIViewController 
{ 
    id <AddViewControllerDelegate> delegate; 
} 
@property (retain) id delegate;

ViewAlarmController.h：

@protocol ViewAlarmControllerDelegate <NSObject> 

- (void)changeAlarm:(AlarmObject *)alarm atIndex:(int) alarmID; 
- (void)deleteAlarmAtIndex:(int) alarmID; 

@end 

@interface ViewAlarmController : UIViewController 
{ 
    id <ViewAlarmControllerDelegate> delegate; 
} 

@property (retain) id delegate;

然後在HomeViewController.h我進口休耕：

#import "AddViewController.h" 
#import "ViewAlarmController.h" 
#import "AlarmObject.h" 
@interface HomeViewController : UITableViewController <AddViewControllerDelegate, ViewAlarmControllerDelegate>

我有方法的下一個聲明爲HomeViewController.m

- (void)addAlarm:(AlarmObject *)alarm{ 
    [self.items addObject:alarm]; 
    [self.tableView reloadData]; 
    NSLog (@"added"); 
} 

- (void)deleteAlarmAtIndex:(int)alarmID{ 
    NSLog(@"alarmID: %d", alarmID); 
    [self.items removeObjectAtIndex:alarmID]; 
    NSLog(@"items: %@", items); 
    [self.tableView reloadData]; 
} 

- (void)changeAlarm:(AlarmObject *)alarm atIndex:(int)alarmID{ 
    NSLog(@"change"); 
}

ViewAlarmController.m協議的方法的代碼塊的調用：

- (IBAction)save:(id)sender { 
    AlarmObject* alarmObj = [[AlarmObject alloc]init]; 
    if(![self.alarmNameField.text isEqual: @""]){ 
     [alarmObj setValue:self.alarmNameField.text forKey:@"alarmName"]; 
     NSLog (@"change alarm id = %d", alarmID); 
     [self.delegate changeAlarm:alarmObj atIndex:alarmID]; 
    } 
    [self dismissViewControllerAnimated:YES completion:nil]; 
} 

- (IBAction)reverse:(id)sender { 
    alarmNameField.text = [alarm valueForKey:@"alarmName"]; 
} 

- (IBAction)deleteAlarm:(id)sender { 
    NSLog (@"delete alarm id: %d",alarmID); 
    [self.delegate deleteAlarmAtIndex:alarmID]; 
    [self dismissViewControllerAnimated:YES completion:nil]; 
}

的問題是，addAlarm作品，但是當我去到ViewAlarm中，我按下按鈕來刪除或保存更改，但不會調用deleteAlarmAtIndex和changeAlarm方法。

的問題是在未來的方法：

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{ 
    if ([segue.identifier isEqualToString:@"addAlarmSegue"]){ 
     AddViewController *avc = segue.destinationViewController; 
     avc.delegate = self; 
    }else if ([segue.identifier isEqualToString:@"viewAlarmSegue"]){ 
     NSIndexPath *selectedRowIndex = [self.tableView indexPathForSelectedRow]; 
     ViewAlarmController *vac = segue.destinationViewController; 
     [vac getObject:[self.items objectAtIndex:selectedRowIndex.row] withId:selectedRowIndex.row]; 

     vac.delegate = self; 
    } 
}

我沒有寫vac.delegate = self;

來源

2013-02-20 user1792771

什麼是重要的是你在哪裏設置委託，以及當你對這些功能進行調用時是否爲零。你可能想發佈，因爲它可能是你的問題。 – rooster117 2013-02-20 17:30:45

我同意，'delegate'最有可能是'nil'。 – Kevin 2013-02-20 17:37:35

我編輯了帖子並添加了調用代碼塊。以同樣的方式，我從它的協議調用addViewController方法，併爲它工作。 – user1792771 2013-02-20 17:37:43

確保對象應該符合你的協議不是nil

My1Object *a = [My1Object new]; 
My2Object <Myprotocol> *b = [My2Object new]; 

a.delegate = b; 

@interface My1Object <MyProtocol> 

@property (nonatomic, weak /* or 'unsafe_unretained' for iOS less than 5.0*/) id <MyProtocol> delegate; 

@end 

@implementation My1Object 

... 



- (void)somethingHappened { 
    // just for check as I said: 
    NSLog(@"self.delegate = %@", self.delegate); // make sure this is not nil! 
    if ([self.delegate respondsToSelector:@selector(myProtocolMethod:)]) { 
     [self.delegate myProtocolMethod:self]; 
    } 
} 

... 

@end

記住你不應該保留（強）你的代表！

來源

2013-02-20 17:52:17 iiFreeman

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