IOS - UICollectionView

Question

I have the following code which works out which section/data index to pass to a destination controller based on the clicked cell.

- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {


    self.selectedItIndex = indexPath.row; // define NSInteger selectedItemIndex property in your interface
    self.selectedSection = indexPath.section;



}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
    if ([segue.identifier isEqualToString:@"sightSeg"]) {

    NSString *s = self.sectionData[_selectedSection];
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"siteSection like %@", s];
    NSArray *filteredArr = [self.sightsArray filteredArrayUsingPredicate:pred];
    NSLog(@"Value of hello = %@", filteredArr);
    sightsObject *rightS = filteredArr[_selectedItIndex];
    _finNo = _selectedItIndex +=1;
    NSLog(@"balls = %@",rightS );
     SightViewController *destController = (SightViewController *)segue.destinationViewController;
    destController.viewTit = rightS.siteTitle;
}

}

The code works fine first try (as in the correct data is passed relevant to the cell/section clicked) - the issue I have is that if you return to the parent controller and select another cell - the same information is passed again - if you repeat the process selecting a 3rd cell - the data for the second cell clicked is passed - so its as though its a step out of sync!?

Can anyone offer any advice? - Is there a way to only run the sgue code once the values have been set in the didselectpath method?

Answer 1

The sender parameter in prepareForSegue will be the collection view cell you've tapped. Use the following code to derive your index at the point of sending:

NSIndexPath *selectedIndexPath = [self.collectionView indexPathForCell:sender];

You don't need the code in didSelectItem...

Answer 2

尝试在prepareForSegue:内调用[collectionView indexPathsForSelectedItems]以获取索引路径，而不是将其保存在collectionView:didSelectItemAtIndexPath: