UICollectionView with UIViewController As Data Source - ios

Question

I have an array of dictionary with the first key as an image. I'm using UIViewController as the data source.
#interface myViewController () {
NSMutableArray *textureArray1;
NSMutableDictionary *dict1;
UIImage *key1a; // UIImage
NSString *key1b; // texture name
}
I don't have trouble populating this dictionary array with a TableView control laid out in the UIViewController.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
}
UIImage *image = [[textureArray1 objectAtIndex:indexPath.row] objectForKey:key1a];
cell.textLabel.text = [[textureArray1 objectAtIndex:indexPath.row] objectForKey:key1b];
cell.imageView.image = image;
return cell;
}
I want to do something new. And I want to populate the same array of images with UICollectionView where, again, UIViewController is the data source. Unfortunately, many tutorials that I find on the Internet have UICollectionViewController as the data source. Anyway, I have the following lines of code.
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"cell" forIndexPath:indexPath];
cell.backgroundColor = [UIColor colorWithPatternImage:[[textureArray1 objectAtIndex:indexPath.row] objectForKey:key1b]];
return cell;
}
And the application crashes with an error that says "unrecognized selector sent to instance..." Well, I don't know how to use UICollectionView. So how do you use UICollectionView with UIViewController?
Thank you for your help.
P.S. The following is the error message.
2013-03-20 10:21:07.777 iPadapp[2023:c07] -[__NSCFString _tiledPatternColor]: unrecognized selector sent to instance 0xdeacdf0
2013-03-20 10:21:07.778 iPadapp[2023:c07] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFString _tiledPatternColor]: unrecognized selector sent to instance 0xdeacdf0'

Answer 1

You need to say that your UIViewController is a UICollectionViewDataSource and UICollectionViewDelegate in your header. See this answer

Answer 2

This is a simple example. Your viewController should be conformed to UICollectionViewDelegate and UICollectionViewDelegateFlowLayout
- (void)viewDidLoad
{
[super viewDidLoad];
// Create the collection view and add it as a sub view
UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];
layout.itemSize = CGSizeMake(120, 120);
layout.sectionInset = UIEdgeInsetsMake(20, 20, 20, 20);
layout.minimumInteritemSpacing =10.0f;
layout.minimumLineSpacing = 10.0f;
self.collectionView = [[UICollectionView alloc] initWithFrame:self.view.bounds collectionViewLayout:layout];
self.collectionView.autoresizingMask = UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;
self.collectionView.backgroundColor = [UIColor whiteColor];
self.collectionView.delegate = self;
self.collectionView.dataSource = self;
[self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:#"cell"];
[self.view addSubview:self.collectionView];
}
// Implement the required data source methods
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return 50;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellId =#"cell";
CustomCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellId forIndexPath:indexPath];
cell.backgroundColor = [UIColor redColor];
return cell;
}