DDCollectionViewFlowLayout 1.1

You want to add pod 'DDCollectionViewFlowLayout', '~> 1.1' similar to the following to your Podfile:

target 'MyApp' do
  pod 'DDCollectionViewFlowLayout', '~> 1.1'
end

Then run a pod install inside your terminal, or from CocoaPods.app.

Alternatively to give it a test run, run the command:

pod try DDCollectionViewFlowLayout

DDCollectionViewFlowLayout 1.1

By
DeJohn Dong

a CollectionViewFlowLayout implement the Waterfall Effect, it's also supported mutiple sections.
you can custom the header & footer, you also can custom the UICollectionViewCell.
now, you can set header sticky on the top when you scroll the collectionView in version 0.5.

##Effects Please clicked this link to see effect one
Please clicked this link to see effect two

##Installation

Alternatively, you can just drag the files from DDCollectionViewFlowLayout / Classes into your own project.

Usage

To run the example project; clone the repo, and run pod install from the Project directory first.

1.example like Wechat photo wall effect

    DDCollectionViewFlowLayout *layout = [[DDCollectionViewFlowLayout alloc] init];
    layout.delegate = self;
    layout.enableStickyHeaders = YES; //set the header sticky if you want
    [self.collectionView setCollectionViewLayout:layout];

implemention the DDCollectionViewDelegateFlowLayout & UICollectionViewDataSource @required or @optional methods

DDCollectionViewDelegateFlowLayout inherit UICollectionViewDelegateFlowLayout Protocol.

code:

- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
    return [[dataDict allKeys] count];
}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
    sortedArray = [[dataDict allKeys] sortedArrayUsingSelector:@selector(compare:)];
    return [dataDict[sortedArray[section]] count];
}

- (NSInteger)collectionView:(UICollectionView *)collectionView layout:(DDCollectionViewFlowLayout *)layout numberOfColumnsInSection:(NSInteger)section{
    return 4;
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    PhotoCell *cell = (PhotoCell *)[collectionView dequeueReusableCellWithReuseIdentifier:@"PhotoCell" forIndexPath:indexPath];
    NSURL *url = dataDict[sortedArray[indexPath.section]][indexPath.row];
    [_assetLibrary assetForURL:url
                   resultBlock:^(ALAsset *asset) {
                       [cell.photo setImage:[UIImage imageWithCGImage:asset.thumbnail]];
                   }
                  failureBlock:^(NSError *error) {
                  }];
    return cell;
}

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath{
    if(kind == UICollectionElementKindSectionHeader){
        UICollectionReusableView *header = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"header" forIndexPath:indexPath];
//        header.backgroundColor = [UIColor colorWithRed:0/255.0 green:0/255.0 blue:0/255.0 alpha:0.5f];
        UILabel *lblTitle = (UILabel *)[header viewWithTag:2];
        lblTitle.text = sortedArray[indexPath.section];
        return header;
    }
    return nil;
}

#pragma mark - UICollectionView Delegate Methods

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section{
    return 1;
}

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section{
    return 1;
}

- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section{
    return UIEdgeInsetsMake(1, 1, 1, 1);
}

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{
    return CGSizeMake(80, 80);
}

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section{
    return CGSizeMake(self.view.bounds.size.width, 30);
}

2.effect like waterfall

example code:

#pragma mark - UICollectionView DataSource Methods

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

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
    return dataList.count;
}

- (NSInteger)collectionView:(UICollectionView *)collectionView layout:(DDCollectionViewFlowLayout *)layout numberOfColumnsInSection:(NSInteger)section{
    return 3;
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    WaterfallCell *cell = (WaterfallCell *)[collectionView dequeueReusableCellWithReuseIdentifier:@"PhotoCell" forIndexPath:indexPath];
    ALAsset *set = dataList[indexPath.item];
    [cell.photo setImage:[UIImage imageWithCGImage:set.thumbnail]];
    return cell;
}

#pragma mark - UICollectionView Delegate Methods

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section{
    return 5;
}

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section{
    return 5;
}

- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section{
    return UIEdgeInsetsMake(5, 5, 5, 5);
}

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{
    return CGSizeMake(100, 100 + indexPath.item % 20);
}

Protocol Methods

- (NSInteger)collectionView:(UICollectionView *)collectionView layout:(DDCollectionViewFlowLayout *)layout numberOfColumnsInSection:(NSInteger)section;

DDCollectionViewDelegateFlowLayout inherit UICollectionViewDelegateFlowLayout Protocol. so you can use all the UICollectionViewDelegateFlowLayout protocal methods in DDCollectionViewDelegateFlowLayout

Updates

0.5 add the header sticky feature
0.4 code optimzation about the UI

Requirements

Xcode 6
iOS 6.0

Author

DeJohn Dong, [email protected]

License

DDCollectionViewFlowLayout is available under the MIT license. See the LICENSE file for more info.