CollectionView Pull-to-Refresh Crashes

Question

I have the following code for my pull-to-refresh "feature" (refreshing a CollectionView

UIRefreshControl *refreshControl = UIRefreshControl.alloc.init;
[refreshControl addTarget:self action:@selector(startRefresh:)
         forControlEvents:UIControlEventValueChanged];
[self.collectionView addSubview:refreshControl];

However, this will crash my app with the following error message:

[CollectionViewController startRefresh:]: unrecognized selector sent to instance 0x7543610
2013-03-24 12:20:10.049 

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[CollectionViewController startRefresh:]: unrecognized selector sent to instance 0x7543610'

What am I missing here? Thanks!

did you have a `startRefresh` method implemented?, if so, did this method takes an argument? — tkanzakic, Mar 24 '13 at 13:23
- (void) startRefresh:(UICollectionView *)startRefresh { [self.collectionView reloadData]; } — schnabler, Mar 24 '13 at 14:22
this "works" (as in "does not crash the app"), however, the indiciator will spin forever and it seems like no changes are made to the collection view. — schnabler, Mar 24 '13 at 14:23
you have to call `[refreshControl endRefreshing];` to stop the animation — tkanzakic, Mar 24 '13 at 14:25

Fran Sevillano · Answer 1 · 2013-03-24T13:37:49.073

1

Make sure your startRefresh: method takes an argument, that's what the colon in @selector(startRefresh:) means. The error that you are getting means that it cannot find the method and execute it.

To know what a selector is and the correct way to implement the target-action pattern, I recommend you to take a look at the docs, here and here.

edited Mar 24 '13 at 13:37

answered Mar 24 '13 at 11:47

Fran Sevillano

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thanks for your answer, but I still wouldn't know how to fix it. i'm not too familiar with @selectors. can you elaborate some more? thank you. – schnabler Mar 24 '13 at 12:15
thanks. i think this helped, but now i'm running into more problems. (as you can see above). quite sure, this is somewhat more tricky than an ios rookie like me can handle ;) – schnabler Mar 24 '13 at 14:26

CollectionView Pull-to-Refresh Crashes

1 Answers1