Reusing cell causes unwanted behaviour when updating cell view - ios

Question

I want ot set a border to a selected cell, i save a cell property that represents the selected one and manipulate it:
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{
NSArray *eyeArray = [self eyesArrayConfigure][indexPath.row];
if (indexPath.row==5) {
int r = arc4random() % 6;
eyeArray = [self eyesArrayConfigure][r];
}
[borderedCell.contentView.layer setBorderWidth:0.0f] ;
UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
borderedCell = cell;
[borderedCell.contentView.layer setBorderColor:self.view.tintColor.CGColor];
[borderedCell.contentView.layer setBorderWidth:3.0f];
}
and the cellForView: (Im usinng 2 types of cell identifiers because one cell contains a label - "Random cell":
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
if (indexPath.row ==5) {
UICollectionViewCell *randomCell =[collectionView
dequeueReusableCellWithReuseIdentifier:#"randomCell"
forIndexPath:indexPath];
randomCell.backgroundColor = [UIColor purpleColor];
borderedCell = randomCell;
[borderedCell.contentView.layer setBorderColor:self.view.tintColor.CGColor];
[borderedCell.contentView.layer setBorderWidth:3.0f];
return randomCell;
}
UICollectionViewCell *myCell = [collectionView dequeueReusableCellWithReuseIdentifier:#"cell" forIndexPath:indexPath];
NSArray *eyeArray = [self eyesArrayConfigure][indexPath.row];
myCell.backgroundView = [[UIImageView alloc] initWithImage:eyeArray[1]];
return myCell;
}
What i get is if a click one cell it will be fine till i scroll and then i get weird behaviour when couple of cells might be with the border.
Thanks for the help.

Answer 1

The solution is to use a view model. You are already doing this for your cells' background views. Apply the same concept for the border.
#interface MyCollectionView ()
#property (nonatomic) NSInteger selectedRow;
#end
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
//update self.selectedRow and either reload entire collection view or just the currently selected and previously selected.
self.selectedRow = indexPath.row;
[collectionView reloadData];
}
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell *myCell = [collectionView dequeueReusableCellWithReuseIdentifier:#"cell" forIndexPath:indexPath];
CGFloat borderWidth = (indexPath.row == self.selectedRow) ? 3.0 : 0.0;
[myCell.contentView.layer setBorderWidth:borderWidth];
return myCell;
}