Uicollectionview - Diddeselectitematindexpath Not Called If Cell Is Selected

UICollectionView - didDeselectItemAtIndexPath not called if cell is selected

The issue is, that the cell is selected, but the UICollectionView does not know anything about it. An extra call for the UICollectionView solves the problem:

[collectionView selectItemAtIndexPath:indexPath animated:NO scrollPosition:UICollectionViewScrollPositionNone]; 

Full code:

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"Cell" forIndexPath:indexPath];
    cell.selected = YES;
    [collectionView selectItemAtIndexPath:indexPath animated:NO scrollPosition:UICollectionViewScrollPositionNone];
    return cell;
}

I keep the question to help someone who may face the same problem.

UICollectionView DidDeselectItemAtIndexPath method not called in Swift

If the parent Class doesn't implement a delegate method, any Subclass won't be able to do it either.

Please make sure the Class you are Subclassing implements it.

didDeselectItemAtIndexPath is not working when reloadData is called

func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath){

    var cell : CollectionViewCell = collectionView.cellForItemAtIndexPath(indexPath) as! CollectionViewCell
    cell.backgroundColor = UIColor.magentaColor()
    self.mediaModels[indexPath.row].isSelected  = true
    cell.selected = true
    cell.imageTicked.hidden = false
}
func collectionView(collectionView: UICollectionView, didDeselectItemAtIndexPath indexPath: NSIndexPath){

    var cell : CollectionViewCell = collectionView.cellForItemAtIndexPath(indexPath) as! CollectionViewCell
    cell.backgroundColor = UIColor.whiteColor()
    self.mediaModels[indexPath.row].isSelected  = false
    cell.selected = false
    cell.imageTicked.hidden = true
}

I get it to work without reloading the data. Just set the imageTicked hidden in the didSelectItemAtIndexPath and didDeselectItemAtIndexPath method. Thanks.

Swift 2 - Fatal Error when `didDeselectItemAtIndexPath` is called

Crash happened because the cell that you selected and scrolled out of the visible region of the screen had been reused for other cells in the collection view. Now, when you try to fetch that selected cell in didDeselectItemAtIndexPath using cellForItemAtIndexPath, it resulted in a crash.

To avoid crash, as mentioned by @Michael Dautermann, use optional binding to validate if the cell is nil and then set the alpha

func collectionView(collectionView: UICollectionView, didDeselectItemAtIndexPath indexPath: NSIndexPath) {
    if let cell = collectionView.cellForItemAtIndexPath(indexPath) {
        cell.alpha = 1.0
    }
}

In order to persist your selection state during scrolling, check the cell's selection state and set your alpha value accordingly when you dequeue your cell in cellForItemAtIndexPath method

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath)

    if cell.selected {
        cell.alpha = 0.4
    }
    else {
        cell.alpha = 1.0
    }

    return cell
}

UICollectionView issue with Select/Deselect cell

As I understand, you want your collectionView can only select 1 cell at a time and if selected cell is clicked again, it will be deselected. If I'm misunderstanding anything, please tell me.

First

• You shouldn't change textColor of day in didSelectItemAtIndexPath and didDeselectItemAtIndexPath methods. Because when you scroll collectionView, cells will be reused and color of day will be wrong for some cells.

• To resolve it, using property selected of UICollectionViewCell.

  SmartCalendarDayCell.m

  - (void)setSelected:(BOOL)selected {
    [super setSelected:selected];
  
    if (selected) {
      self.day.textColor = [UIColor colorWithHexString:@"#D97E66" setAlpha:1];
    } else {
      self.day.textColor = [UIColor lightGrayColor];
    }
  }
  

Second

• To deselect selected cell, you should check and do it on collectionView:shouldSelectItemAtIndexPath: method.

  - (BOOL)collectionView:(UICollectionView *)collectionView shouldSelectItemAtIndexPath:(NSIndexPath *)indexPath {
    if ([collectionView.indexPathsForSelectedItems containsObject:indexPath]) {
      [collectionView deselectItemAtIndexPath:indexPath animated:NO];
      return NO;
    }
  
    return YES;
  }
  

For more detail, you can check my demo repo here.

UICollectionView's didSelectItemAtIndexPath only called when selecting cell with two fingers

The solution: The collection view was added on top of a view containing a single-tap gesture recogniser. This some how caused this behaviour. I removed the recogniser from the collection views parent view and it works.

Feel free to explain why this is expected behaviour. I would have argued that the top most view (CollectionView) handles the touches before they are passed to the view behind.

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