Safely perform batch updates in UITableView and UICollectionView
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README.md

BMACollectionBatchUpdates Build Status codecov.io CocoaPods Compatible

BMACollectionBatchUpdates is a set of classes to generate updates and extensions to UICollectionView and UITableView to perform them safely in a batch manner.

How to use

In order to generate the mentioned updates it has to make collection item and section conform the BMAUpdatableCollectionItem andBMAUpdatableCollectionItem protocols respectively:

@interface BMAExampleItemsSection : NSObject <BMAUpdatableCollectionSection>
@end

@interface BMAExampleItem : NSObject <BMAUpdatableCollectionItem>
@end

Once both old and new data models are available, it has to calculate changes and apply them:

@implementation BMAExampleCollectionViewController

- (void)setSections:(NSArray *)sections {
	[BMACollectionUpdate calculateUpdatesForOldModel:self.sections
                                            newModel:sections
                               sectionsPriorityOrder:nil
                                eliminatesDuplicates:YES
                                          completion:^(NSArray *sections, NSArray *updates) {
                                          		[self.collectionView bma_performBatchUpdates:updates applyChangesToModelBlock:^{
											        _sections = sections;
											    } reloadCellBlock:^(UICollectionViewCell *cell, NSIndexPath *indexPath) {
											        [self reloadCell:cell atIndexPath:indexPath];
											    } completionBlock:nil];
                                          }];
}

@end
@implementation BMAExampleTableViewController

- (void)setSections:(NSArray *)sections {
	[BMACollectionUpdate calculateUpdatesForOldModel:self.sections
                                            newModel:sections
                               sectionsPriorityOrder:nil
                                eliminatesDuplicates:YES
                                          completion:^(NSArray *sections, NSArray *updates) {
                                          		[self.collectionView bma_performBatchUpdates:updates applyChangesToModelBlock:^{
											        _sections = sections;
											    } reloadCellBlock:^(UITableViewCell *cell, NSIndexPath *indexPath) {
											        [self reloadCell:cell atIndexPath:indexPath];
											    } completionBlock:nil];
                                          }];
}

@end

Generating cell update for existing BMAUpdatableCollectionItem

BMAUpdatableCollectionItem conforms to NSObject protocol and by doing so it provides isEqual method for comparing items. In most cases comparing uids in isEqual will be enough, but sometimes your model may contain additional properties that can change and requie cell update.

Simple example: online status which can be either online or offline. When it changes we need to gerenrate cell update for this item. To detect this change isEqual can be implemented in following way:

- (BOOL)isEqual:(id)object {
    if (self == object) {
        return YES;
    }

    if (![object isKindOfClass:[self class]]) {
        return NO;
    }

    BMAExampleItem *item = (BMAExampleItem *)object;
    return [self.uid isEqual:item.uid] && self.isOnline == item.isOnline;
}

@end

How to install

Using CocoaPods

  1. Include the following line in your Podfile:

    pod 'BMACollectionBatchUpdates', '~> 1.1'
    

    If you like to live on the bleeding edge, you can use the master branch with:

    pod 'BMACollectionBatchUpdates', :git => 'https://github.com/badoo/ios-collection-batch-updates'
    
  2. Run pod install

Manually

  1. Clone, add as a submodule or download.
  2. Add all the files under BMACollectionBatchUpdates to your project.
  3. Make sure your project is configured to use ARC.

License

Source code is distributed under MIT license.

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