在NSSet objective中插入索引路径-C

Question

是否可以在NSSET中插入索引路径值？基本上，我试图将indexPath插入到我的NSSet中，NSSet是我的CollectionView中所有旋转的GreenCells的集合，但是由于某种原因，它没有工作:\这是我的代码:ViewController.m

编辑:我添加了所有的代码，使它更容易。

#import "ViewController.h"
//#import "CollectionViewTest-Swift.h"
#import "CustomCollectionViewCell.h"
#import "AppDelegate.h"



@interface ViewController ()<UICollectionViewDelegate, UICollectionViewDataSource, ImpressionStalkerDelegate, UIScrollViewDelegate, UICollectionViewDelegateFlowLayout>

@property NSArray *indexPathsOfCellsTurnedGreen_Arr;
@property NSMutableSet *indexPathsOfSeenCells;

@property ImpressionStalker *impressionEventStalker;




@end

@implementation ViewController
{
}



@synthesize Collection_view;




- (void)viewDidLoad {
    [super viewDidLoad];
    self.impressionEventStalker = [[ImpressionStalker alloc] initWithMinimumPercentageOfCell:0.70 collectionView:Collection_view delegate:self];
    
    AppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
    appDelegate.myViewController = self;
    
}


- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    
}

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
    //    [impressionEventStalker stalkCells];
}


- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return 100;
}



// The cell that is returned must be retrieved from a call to -dequeueReusableCellWithReuseIdentifier:forIndexPath:
- (__kindof UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    
    CustomCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"CELL_ID" forIndexPath:indexPath] ;
    
    //    cell.textLabel.text = [NSString stringWithFormat:@"%ld", indexPath.row];
    
    [cell configure:[NSString stringWithFormat:@"%ld", indexPath.row] configure: NO];
    
    //    cell.cellBackground.backgroundColor = [UIColor redColor];
    
    //    if ([_indexPathsOfCellsTurnedGreen_Arr containsObject:indexPath]) {
    //        cell.cellBackground.backgroundColor = [UIColor greenColor];
    //    } else {
    //        cell.cellBackground.backgroundColor = [UIColor redColor];
    //
    //    }
    
    if ([_indexPathsOfSeenCells containsObject:indexPath]) {
        cell.cellBackground.backgroundColor = [UIColor greenColor];
    } else {
        cell.cellBackground.backgroundColor = [UIColor redColor];
        
    }
    
    return cell;
}


- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
    return CGSizeMake( [ [UIScreen mainScreen]bounds ].size.width - 40, 325);
}

- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section{
    return UIEdgeInsetsMake(0, 20, 0, 20);
}


- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return 1;
}



- (void)collectionView:(UICollectionView *)collectionView willDisplayCell:(UICollectionViewCell *)cell forItemAtIndexPath:(NSIndexPath *)indexPath
{
    [(CustomCollectionViewCell*)cell startTimer:^{
        [self.impressionEventStalker stalkCells];
    }];
    
    
}


- (void)collectionView:(UICollectionView *)collectionView didEndDisplayingCell:(UICollectionViewCell *)cell forItemAtIndexPath:(NSIndexPath *)indexPath
{
    [(CustomCollectionViewCell*)cell stopTimer];
}



- (void)sendEventForCellAtIndexPath:(NSIndexPath * _Nonnull)indexPath {
    
    CustomCollectionViewCell *cell = (CustomCollectionViewCell*)[Collection_view cellForItemAtIndexPath:indexPath];
    cell.cellBackground.backgroundColor = [UIColor greenColor];
    
    
    //    [_indexPathsOfCellsTurnedGreen_Arr arrayByAddingObject:indexPath];
    //    [_indexPathsOfSeenCells setByAddingObject:indexPath];
    [_indexPathsOfSeenCells setByAddingObject:indexPath];
    NSLog(@"%lu",(unsigned long)_indexPathsOfSeenCells.count);
}



// A func which sends all the seen cells to the server:.
- (NSSet*)sendStalkDataToServer {
    
    return _indexPathsOfSeenCells;
}




@end

ViewController.h

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController


@property (strong, nonatomic) IBOutlet UICollectionView *Collection_view;

- (NSSet*)sendStalkDataToServer;

@end

Answer 1

null

self.indexPathsOfSeenCells = [self.indexPathsOfSeenCells setByAddingObject:indexPath];

但是，理想情况下应该使用可变集，即 。

使用可变集，您可以简单地:

[self.indexPathsOfSeenCells addObject:indexPath];

还要注意，您的集合从未初始化，因此它始终是 。

你必须把:

self.indexPathsOfSeenCells = [NSMutableSet set];

某处。