didSelectItemAtIndexPath / didDeselectItemAtIndexPath in PSTCollectionView in iOS - ios

Question

I'm working with UICollectionView using PSTCollectionView
Library. I've to create a grid where user can select and deselect
images by tapping on UICollectionViewCell. I've to show checkBox like
image if cell is selected. And uncheckedBox image if cell is
deselected. I am able to select cell and display checkBox image.And
also can deselect. But when I select next cell, the previous deselected
cell also get selected and shows checkBox image. This is the method I declared in UICollectionViewCell subClass
-(void)applySelection{
if(_isSelected){
_isSelected=FALSE;
self.contentView.backgroundColor=[UIColor whiteColor];
self.selectImage.image=[UIImage imageNamed:#"unchecked_edit_image.png"];
}else{
_isSelected=TRUE;
self.contentView.backgroundColor=[UIColor whiteColor];
self.selectImage.image=[UIImage imageNamed:#"checked_edit_image.png"];
}
}
And here is my code for didSelectItemAtIndexPath and
didDeselectItemAtIndexPath
- (void)collectionView:(PSTCollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"didSelect method called");
FriendImageCell *cell = (FriendImageCell*)[imageGrid cellForItemAtIndexPath:indexPath];
[selectedImages addObject:[[list objectAtIndex:indexPath.item] objectForKey:#"thumbnail_path_150_150"]];
[cell applySelection];
}
- (void)collectionView:(PSTCollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"did deselect called");
FriendImageCell *cell = (FriendImageCell*)[imageGrid cellForItemAtIndexPath:indexPath];
[selectedImages removeObjectAtIndex:indexPath.item];
[cell setSelected:NO];
[cell applySelection];
}
Can anyone please make me understand whats wrong with my code ? Make
me correct if I'm doing anything wrong. Tried many answers on
stack-overflow but nothing worked. Any help would be appreciated.
Thanks in advance.

Answer 1

After days of back and forth discussion. I think I finally understand what your problem really is. You must have forgotten to set the allowsMultipleSelection to YES. So whenever a new cell is selected, your previous cells got deselected.
allowsMultipleSelection
This property controls whether multiple items can be selected simultaneously. The default value of this property is NO.
And in my previous answer, I also suggested you to make your own boolean array to keep track of the selected items. However, I just realized that you don't have to. indexPathsForSelectedItems gives you an array of selected index paths.
indexPathsForSelectedItems
An array of NSIndexPath objects, each of which corresponds to a single selected item. If there are no selected items, this method returns an empty array.
As a matter of fact, you don't even have to implement the didSelectItemAtIndexPath, and didDeselectItemAtIndexPath. By default, these two delegate methods will call setSelected: for you. Therefore, a more appropriate way to do is move your applySelection code in to setSelected.
Overwrite the setSelected: method in your custom UICollectionViewCell.
- (void)setSelected:(BOOL)selected
{
[super setSelected:selected];
// Change your UI
if(_isSelected){
self.contentView.backgroundColor=[UIColor whiteColor];
self.selectImage.image=[UIImage imageNamed:#"unchecked_edit_image.png"];
}else{
self.contentView.backgroundColor=[UIColor whiteColor];
self.selectImage.image=[UIImage imageNamed:#"checked_edit_image.png"];
}
}