UICollectionViewCell shadow color

问题:

In the new UICollectionView I do not see how to add a shadow to a UICollectionViewCell. How would I go about this. Would I add another view?

    [self.collectionView cellForItemAtIndexPath:[self.collectionView indexPathForItemAtPoint:[recognizer locationInView:[self view]]]].layer.shadowPath = [UIBezierPath bezierPathWithRect:rect].CGPath;
    [self.collectionView cellForItemAtIndexPath:[self.collectionView indexPathForItemAtPoint:[recognizer locationInView:[self view]]]].layer.shadowColor = [UIColor yellowColor].CGColor;
    [self.collectionView cellForItemAtIndexPath:[self.collectionView indexPathForItemAtPoint:[recognizer locationInView:[self view]]]].layer.shadowRadius = .5;
    [self.collectionView cellForItemAtIndexPath:[self.collectionView indexPathForItemAtPoint:[recognizer locationInView:[self view]]]].layer.shadowOpacity = .1;

回答1:

You're forgetting to set masksToBounds on UIView to NO. This should work:

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    PhotoCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"PhotoCell" forIndexPath:indexPath];

    cell.layer.masksToBounds = NO;
    cell.layer.borderColor = [UIColor whiteColor].CGColor;
    cell.layer.borderWidth = 7.0f;
    cell.layer.contentsScale = [UIScreen mainScreen].scale;
    cell.layer.shadowOpacity = 0.75f;
    cell.layer.shadowRadius = 5.0f;
    cell.layer.shadowOffset = CGSizeZero;
    cell.layer.shadowPath = [UIBezierPath bezierPathWithRect:cell.bounds].CGPath;
    cell.layer.shouldRasterize = YES;

    return cell;
}

回答2:

[self.collectionView cellForItemAtIndexPath:[self.collectionView indexPathForItemAtPoint:[recognizer locationInView:[self view]]]].layer.masksToBounds = NO;

回答3:

most likely your problem is best solved with the existing answer to How do I draw a shadow under a UIView?

to be specific to your circumstance, you would probably have code that would do what the following code does (depending upon where you get your collectionView and someIndexPath in order to point to the cell you're interested in):

    UICollectionViewCell* collectionViewCell
      = [collectionView dequeueReusableCellWithReuseIdentifier:DEFINED_IDENTIFIER forIndexPath:someIndexPath];
    collectionViewCell.layer.shadowPath = [UIBezierPath bezierPathWithRect:collectionViewCell.bounds].CGPath;

there are obviously other ways to get the cell. the important thing is the 2nd line, to set the shadowPath.

回答4:

You are not setting the shadowOffset property on the layer.

myCell.layer.shadowOffset = CGSizeMake(10,10);

回答5:

Go to the CustomCollectionviewCell.m and try to add this:

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        //////// make shadow  of total view
        self.clipsToBounds = NO;
        self.layer.masksToBounds = NO;
        self.layer.shadowRadius = 5;
        self.layer.shadowOpacity = 0.5;
        self.layer.shadowColor = [UIColor blackColor].CGColor;
        self.layer.shadowOffset = CGSizeMake(0, 1);
        self.layer.shadowPath = [UIBezierPath bezierPathWithRect:self.bounds].CGPath;

        // make radius of the cell
        self.layer.cornerRadius = 5;

    }
    return self;
}