从未调用过的委托方法

Question

first of all here is my code:

@protocol SearchTableViewControllerDelegate

@required
- (void)didSelectFileCardsContent:(FileCardsContent*)content;

@end


@interface SearchTableViewController : UITableViewController <UISearchBarDelegate, UISearchDisplayDelegate>{

    id <SearchTableViewControllerDelegate> delegate;
...
}

@property (nonatomic, assign) id <SearchTableViewControllerDelegate> delegate;
...
@end
---------------------------------------------------

@implementation SearchTableViewController

@synthesize ... delegate;
...
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    FileCardsContent *fileCardToShow = [self.tableData objectAtIndex:indexPath.row];
    [self.delegate didSelectFileCardsContent:fileCardToShow];

}
...
@end
---------------------------------------------------

@interface FileCardsViewCotroller : UIViewController <SearchTableViewControllerDelegate>{
...
@end
---------------------------------------------------

@implementation FileCardsViewCotroller
...
- (void)didSelectFileCardsContent:(FileCardsContent*)content{
    [managedFileCards insertSingleContent:content];
    self.currentFileCardsContent = content;
    questionView1.text = currentFileCardsContent.question;

}
@end

My problem is - (void)didSelectFileCardsContent:(FileCardsContent*)content in FileCardsViewCotroller is never called. There are no compiler warnings or errors. I`m not familiar with protocols and delegates so is suggest there is a conceptually problem. Anny ideas?

Answer 1

first it's good practice to check whether the method exists/is implemented by the delegate

if ([delegate respondsToSelector:@selector(didSelectFileCardsContent:)])
    [delegate didSelectFileCardsContent:fileCardToShow];

don't use self.property when you're calling it in its own class. it executes unnecessary commands when you can just call it directly.

make sure you implemented the protocol in the delegate and implemented the method. make sure you set the delegate to self.

Answer 2

您只是没有将您的委托分配给任何东西，因此消息被发送到nil。