GRProvider

Table of content

• Why to use?
• How to use?
  • Define model
  • Create the instances
  • Setup
  • Show items
  • Basic sample
• Features
  • Table View Provider
  • Collection View Provider
• Animations
• Are you missing some property configuration?
• Installation
• License

Why to use?

Writing the simple scanario, where you want to use the basic implementation of the UITableView or UICollectionView is tedious. You have to implement a lot of delegate methods, even for the simplest use-case. I Example: UITableViewDiffableDataSource accessible in iOS 13 is a simple approach of loading/diffing data in TableView

Learning curve is a little bit tedious, but it's worth for the future programing.

👍 Advantages:

• immutable data binding
• one source of the truth
• no need to do the custom diffing mechanism
• avoids synchronization bugs, exceptions and crashes
• avoids side effects
• uniform approach accross all providers
• simple usage of animations using provider with DeepDiff library or provider using UITableViewDiffableDataSource

👎 Disadvantages:

• learning curve
• Not a good solution for the complicated/advanced usa case of the TableView or CollectionView
• different approach than the standard Apple iOS API
• usage of the third part diffing library DeepDiff
• contains only the most used delegates methods
• still in the development process

Look at this simple code you just need to write, to show data in Table View:

lazy var tableProvider = GRSimpleTableViewProvider<Int> { provider, tv, indexPath, item in
    guard let cell = tv.dequeueReusableCell(fromClass: SimpleTableViewCell.self, for: indexPath) else { return UITableViewCell() }
    cell.titleLabel.text = "Item with value: \(item)"
    return cell
}

private func showItems() {
    tableView.items(tableProvider, items: [1, 2, 3, 4, 5, 6, 7], animated: true)
}

That's all you need to do, when showing simple data in the TableView. Isn't that great? That's all you need to do.

No need of:

• assigning tableView.delegate = self & tableView.dataSource = self
• implementation of any DataSource/Delegate methods
• No need of casting/accessing the cell item property in collection (Arrays etc.)

How to use?

You can use this type of GRProviders:

1. GRSimpleTableViewProvider -> Use in case of you have just one section in the UITableView
2. GRTableViewProvider -> Default provider for the UITableView
3. GRDiffableTableViewProvider -> Inherits all functionality of GRTableViewProvider but uses UITableViewDiffableDataSource API for diffing and animating
4. GRDeepDiffTableViewProvider -> Inherits all functionality of GRTableViewProvider but uses DeepDiff framework for diffing and animating. More info about framework click here.
5. GRCollectionViewProvider -> Default provider for the CollectionView
6. GRDeepDiffCollectionViewProvider -> Inherits all functionality of GRCollectionViewProvider but uses DeepDiff framework for diffing and animating. More info about framework click here.
7. GRDiffableCollectionViewProvider -> CollectionView provider that uses UICollectionViewDiffableDataSource as a data source and leaves the layout handling for collectionViewLayout. It is recommended to use this provider alongside UICollectionViewCompositionalLayout or any custom layout.

Define model

Firstly you need to model your data, showed in the UITableView or UICollectionView using any type you choose.

For example:

/// using Enum as Section & Class as Item
enum Section: Sectionable {
        
    case sectionOne([Item])
    case sectionTwo([Item])

    struct Item {
        let title: String       
    }
    
}

/// using Class as a Section & Enum as an Item
class Section: Sectionable {
    let items: [Item]
    
    enum Item {
        case title
        case divider
        case advertisement
    }
    
}

/// Define only items without sections
enum Item {
    case title
    case divider
    case advertisement
}

You can model it, based on your preference. It's all up to you.

Create the instance of the UITableView and provider you choose

@IBOutlet weak var tableView: UITableView!
private let tableProvider = GRSimpleTableViewProvider<Item>()

Setup your provider

private func setupTableProvider() {            
    tableProvider.configureCell = { provider, tableView, index, item in              
        switch item {
        case .advertisement:
        return tableView.dequeueReusableCell(....)
        case .divider:
        return tableView.dequeueReusableCell(....)
        case .title:
        return tableView.dequeueReusableCell(....)
        }                   
    }
}

Show items in the UITableView

private func showItems() {            
    let items: [Item] = [.title,
                         .divider,
                         .advertisement,
                         .divider,
                         .advertisement]
                         
    tableProvider.bind(to: tableView, items: items)
}

🔥 That's it. All you need to do to show the simple list with 2 advertisements and title in few lines of code. 🔥

All together

Show list of strings in table view.

import UIKit
import GRProvider

class ViewController: UIViewController {

    @IBOutlet weak var tableView: UITableView!
    
    private let tableProvider = GRSimpleTableViewProvider<String>()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        title = "Simple Table View Provider"
        
        setupTableView()
        showItems()
    }

    private func setupTableView() {
        tableProvider.estimatedHeightForRow = 100
                
        tableProvider.configureCell = { _, tv, index, title in
            guard let cell = tv.dequeueReusableCell(fromClass: SimpleTableViewCell.self, for: index) else { return UITableViewCell() }
            cell.titleLabel.text = title
            return cell
        }
    }
    
    private func showItems() {
        let items = (1...10).map { "Item \($0)" }
        tableProvider.bind(to: tableView, items: items)
    }
    
}

[!WARNING] ⚠️⚠️⚠️ Retain cycle: Be careful when using strong reference inside the closure. In case you need to call self inside the closure, don't forget to use [unowned self] or [weak self]

Features

UITableView Providers

You can choose one of these types of providers:

1. GRSimpleTableViewProvider -> Use in case of you have just one section in the UITableView
2. GRTableViewProvider -> Default provider for the UITableView
3. GRDiffableTableViewProvider -> Inherits all functionality of GRTableViewProvider but uses UITableViewDiffableDataSource API for diffing and animating
4. GRDeepDiffTableViewProvider -> Inherits all functionality of GRTableViewProvider but uses DeepDiff framework for diffing and animating. More info about framework click here.

Features:

1. estimatedHeightForRow: CGFloat
   Setup default estimated height of the dequeued cell.
2. configureEstimatedCellHeight: CellHeightProvider You can provide different height estimation for each cell separatelly.

tableProvider.configureEstimatedCellHeight = { _, _, _, item in
    switch item {
    case .advertisement:
        return 100
    case .divider:
        return 1
    case .title:
        return 24
    }
}

3.configureCellHeight: CellHeightProvider You can provide different height for each cell separatelly.

tableProvider.configureCellHeight = { _, _, _, item in
    switch item {
    case .advertisement:
    return UITableView.automaticDimension
    case .divider:
        return 1
    case .title:
        return 24
    }
}

4. configureCell: CellProvider Configuration for dequeueing cell based on the model provided in the provider instance.

tableProvider.configureCell = { provider, tableView, index, item in              
    switch title {
    case .advertisement:
    return tableView.dequeueReusableCell(....)
    case .divider:
    return tableView.dequeueReusableCell(....)
    case .title:
    return tableView.dequeueReusableCell(....)
    }                   
}

5. configureSectionHeader: SectionHeaderFooterProvider & configureSectionFooter: SectionHeaderFooterProvider Returns UIView showed in the header or te footer.

tableProvider.configureSectionHeader = { provider, section in
    let container = UIView()
    let label = UILabel()
    label.translatesAutoresizingMaskIntoConstraints = false

    container.addSubview(label)

    label.topAnchor.constraint(equalTo: container.topAnchor, constant: 15).isActive = true
    label.leftAnchor.constraint(equalTo: container.leftAnchor, constant: 15).isActive = true
    label.bottomAnchor.constraint(equalTo: container.bottomAnchor, constant: -15).isActive = true
    label.rightAnchor.constraint(equalTo: container.rightAnchor, constant: -15).isActive = true

    label.text = provider.sections[section].title

    return container
}

⚠️ Don't forget to setup height of the header. Ex: tableProvider.heightForHeaderInSection = UITableView.automaticDimension

6. configureSectionHeaderHeight: SectionHeaderFooterHeightProvider & configureSectionFooterHeight: SectionHeaderFooterHeightProvider & heightForFooterInSection: CGFloat & heightForHeaderInSection: CGFloat You can use one of the property from the list about, to configure height for the footer or the header in the section. In case you want to have different sizes use configure methods. Otherwise use heightForFooterInSection and heightForHeaderInSection.
7. configureOnItemSelected: ItemSelectionProvider One of the most used property in the provider. Setup the closure variable to be notified about the selection on the cell.

tableProvider.configureOnItemSelected = { [unowned self] _, _, _, item in
    switch item {
    case .advertisement:
        print("Advertisement clicked")
    case .divider:
        print("Advertisement clicked")
    case .title:
        print("Title clicked")
    }
}

8. configureTrailingSwipeGesture: SwipeGestureProvider & configureLeadingSwipeGesture: SwipeGestureProvider
9. configureDidScroll: ScrollProvider
10. configureRefreshGesture: ScrollProvider Closure is fired, when the table view contains the refresh control. When scrollViewDidEndDragging executes, it automatically checks the refresh control isRefreshing property and fires the event.
11. configureDidEndDragging: DidEndDraggingProvider
12. configureWillEndDragging: WillEndDraggingProvider

UICollectionView Providers

You can choose one of these types of providers:

1. GRCollectionViewProvider -> Default provider for the UICollectionView
2. GRDeepDiffCollectionViewProvider -> Inherits all functionality of the GRCollectionViewProvider but uses the DeepDiff framework for diffing and animating. More info about the framework, click here
3. GRDiffableCollectionViewProvider -> CollectionView provider that uses UICollectionViewDiffableDataSource as a data source and leaves the layout handling for collectionViewLayout. It is recommended to use this provider alongside UICollectionViewCompositionalLayout or any custom layout. Therefore some of the features as cellSize, sectionInsets and others are not available in this provider, selected collectionViewLayout should handle all the layout itself.

Features:

1. configureCell: ItemProvider
2. configureCellSize: ItemSizeProvider
3. configureSupplementaryElementOfKind: SupplementaryViewProvider
4. configureSectionInsets: SectionInsetProvider
5. configureMinLineSpacingForSection: MinLineSpacingProvider
6. configureMinInteritemSpacingForSection: MinLineSpacingProvider
7. configureOnItemSelected: ItemSelectionProvider
8. configureDidScroll: ScrollProvider
9. configureRefreshGesture: ScrollProvider
10. configureWillEndDragging: WillEndDraggingProvider & configureDidEndDragging: DidEndDraggingProvider
11. cellSize: CGSize
12. sectionInsets: UIEdgeInsets
13. minimumLineSpacingForSection: CGFloat
14. minInteritemSpacingForSection: CGFloat

Animating Differences

GRDeepDiffTableViewProvider

DeepDiff is a framework, used in past few years. It's fast with great benchmark against other alghoritms. More info about the library and alghoritm find here.

It works simillarly to the GRDiffableTableViewProvider, with same API but....

What is different?

1. Your Section/Item model definition must comform to the DiffAware protocol.
2. Constructor doesn't require instance of the UITableView unlike the DeepDiffTableViewProvider.
3. You can modify the animation for the insertion, deletion and replacement, what is not currently possible using the DeepDiffTableViewProvider.
4. Available for all versions of iOS starting iOS 11.

GRDiffableTableViewProvider #iOS13

Apple has released the new API for animating differences in table views and collection views called UITableViewDiffableDataSource. You can find the documentation here.

GRProvider uses it's benefits and provides you a custom implementation benefitting on the GRDiffableTableViewProvider. It uses the same API as other providers, so you don't need to worry about the learning curve. All providers shares their API.

What is different?

1. You Section/Item model definition must comform to the Hashable protocol.
2. Constructor of the GRDiffableTableViewProvider requires instance of the UITableView you will use in items binding.

These 2 things are required to animate your items differences in the table view.

GRDeepDiffCollectionViewProvider

Similarly to this section

Are you missing some property configuration?

Just make a subclass of one of the providers and create aditional functionality. It's that simple.

⚠️ Be careful of overriding the current functionality. Use super to prevent misunderstanding.

For example

class CustomSimpleTableViewProvider<Section: Sectionable>: GRTableViewProvider<Section> {
    
    open var configureDidHighlightRow: ((CustomSimpleTableViewProvider, UITableView, Section.Item) -> ())?
    
    func tableView(_ tableView: UITableView, didHighlightRowAt indexPath: IndexPath) {
        configureDidHighlightRow?(self, tableView, sections[indexPath.section].items[indexPath.row])
    }
    
    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        print("Number of rows for section: \(section)")
        return super.tableView(tableView, numberOfRowsInSection: section)
    }
    
}

Installation

Swift Package Manager

Create a Package.swift file.

import PackageDescription

let package = Package(
    name: "SampleProject",
    dependencies: [
        .Package(url: "https://github.com/smajdalf/GRProvider" from: "0.0.1")
    ]
)

If you are using Xcode 11 or higher, go to File / Swift Packages / Add Package Dependency... and enter package repository URL https://github.com/smajdalf/GRProvider, then follow the instructions

License

GRProvider is released under the MIT license. See LICENSE for details.