how to fix NSCollectionViewItem overlap problem? - macos

Question

i use NSCollectionView to display a horizontal list. but all of the cells overlap in the first cell position, like this.
i don't have enough reputation to post images. [cell1,cell2,cell3], they all overlap in the first cell position. so it look like just a cell, but actually it has 3 cells.
my main code:
ViewController.h
- (void)viewDidLoad {
[super viewDidLoad];
self.flowLayout.scrollDirection = NSCollectionViewScrollDirectionHorizontal;
self.collectionView.dataSource = self;
self.collectionView.delegate = self;
self.collectionView.selectable = YES;
self.collectionView.allowsMultipleSelection = YES;
[self.collectionView registerNib:[[NSNib alloc] initWithNibNamed:#"ScreenShotCellView" bundle:nil] forItemWithIdentifier:NSStringFromClass([ScreenShotCellView class])];
}
#pragma mark - NSCollectionViewDataSource
- (NSInteger)numberOfSectionsInCollectionView:(NSCollectionView *)collectionView {
[self.collectionView.collectionViewLayout invalidateLayout];
return 1;
}
- (NSInteger)collectionView:(NSCollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
return self.screenshotItems.count;
}
- (NSCollectionViewItem *)collectionView:(NSCollectionView *)collectionView itemForRepresentedObjectAtIndexPath:(NSIndexPath *)indexPath {
NSCollectionViewItem *itemCell = [self.collectionView makeItemWithIdentifier:NSStringFromClass([ScreenShotCellView class]) forIndexPath:indexPath];
if ([itemCell isKindOfClass:[ScreenShotCellView class]]) {
ScreenShotCellView *cellView = (ScreenShotCellView *)itemCell;
ScreenshotItem *itemData = [self.screenshotItems objectAtIndex:indexPath.item];
cellView.item = itemData;
}
return itemCell;
}
#pragma mark - NSCollectionViewDelegateFlowLayout
- (NSSize)collectionView:(NSCollectionView *)collectionView layout:(NSCollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
return CGSizeMake(100, self.collectionView.frame.size.height - 20);
}
- (CGFloat)collectionView:(NSCollectionView *)collectionView layout:(NSCollectionViewLayout *)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section {
return 10;
}
- (CGFloat)collectionView:(NSCollectionView *)collectionView layout:(NSCollectionViewLayout *)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section {
return 10;
}
How can i do something to fix it?

Answer 1

I have found the reason.
The problem is in my custom cell.
#interface ScreenShotCellView ()
#property (weak) IBOutlet NSView *containerView;
#end
#implementation ScreenShotCellView
- (void)loadView {
self.view = self.containerView;
}
#end
in the loadView method. self.view = self.containerView; make always display in the first cell.
after changed like this, it becomes normal.
- (void)loadView {
self.view = [[NSView alloc] init];
[self.view addSubview:self.containerView];
}