Savory is a swift accordion view implementation.

• Xcode 8.0
• Swift 3.0
• iOS 8

• Using CocoaPods:

  pod 'Savory', :git => 'https://github.com/Nandiin/Savory.git'

• Using Carthage:

  github "Nandiin/Savory"
  

  then proceed with official steps stated in Carthage readme

• Manually:

  Add the files in Savory folder to your project.

import UIKit
import Savory

class ViewController: UIViewController, SavoryViewDelegate {

    var savoryView: SavoryView!

    override func viewDidLoad() {
        super.viewDidLoad()

        /* 1. Initiate SavoryView */
        savoryView = SavoryView(frame: view.frame)
        // offset for status bar
        savoryView.frame.origin.y = 20
        savoryView.frame.size.height -= 20 

        /* 2. Provide a implementation of SavoryStateProtivder protocol */
        // Savory providers a simple implementation - SimpleStateProvider
        savoryView.stateProvider = SimpleStateProvider([.expanded, .collapsed, .collapsed])

        /* 3. Set the reuse identifiers for header and body cells */
        savoryView.headerIdentifier = "header"
        savoryView.bodyIdentifier = "body"

        /* 4. register the reuse identifiers */
        savoryView.register(UITableViewCell.self, forCellReuseIdentifier: "header")
        savoryView.register(UITableViewCell.self, forCellReuseIdentifier: "body")

        /* 5. set the savoryDelegate */
        savoryView.savoryDelegate = self

        /* 6. add subview */
        view.addSubview(savoryView)
    }

    func headerCell(forPanelAt index: SavoryPanelIndex, in savoryView: SavoryView) -> SavoryHeaderCell {

        /* Dequeues a reusable cell */
        // SavoryView provides a method to dequeue reusable header cell for certain index
        // SavoryView internally dequeues a cell using its headerIdentifier as reuse identifier
        let cell = savoryView.dequeueReusableHeaderCell(forPanelAt: index)

        /* customize the cell */
        cell.selectionStyle = .none
        cell.textLabel?.text = "Header \(index)"
        cell.backgroundColor = UIColor.lightGray

        return cell
    }

    func bodyCell(forPanelAt index: SavoryPanelIndex, in savoryView: SavoryView) -> SavoryBodyCell {

        // almost same as headerCell(forPanelAt:in:)
        let cell = savoryView.dequeueReusableBodyCell(forPanelAt: index)
        cell.textLabel?.numberOfLines = 0
        cell.textLabel?.text = [String](repeating: "Body \(index)", count: index + 1).joined(separator: "\n")
        return cell
    }
}

Savory also can be used along with Interface Builder:

• Set Class filed of a Table View to SavoryView in the Identity Inspector.

• Set Identifier fileds of two Table View Cells respectively in the Attributes Inspector.

• Connect Table View to a view controller as outlet.

• Set the headerIdentifier, bodyIdentifier properties of the outlet, you should use the values set for Table View Cells above.

• Set stateProvider and savoryDelegate properties of the outlet.

• Header: The upper title bar of a accordion panel that consumes user selection event and then toggles the visibility of the Body.

• Body: The lower view of a accordion panel that typically carrys detail information and would collapse or expand when user taps the corresponding Header.

Accordion effect view developed on UITableView.

• savoryDelegate: Delegate that provides header and body cells for the view. It also receives event like willCollapse, willExpand, didCollapse, didExpand and didSelect.

• stateProvider: Another delegate that provides the state of the accordion view. SavoryView has stateProvider.count number of panels and i-th panel's expand-or-collapse state depends on the value stateProvider[i].

• headerIdentifier, bodyIdentifier: SavoryView uses these properties inside its dequeueReusableHeaderCell and dequeueReusableBodyCell method to dequeue reusable cells. So make sure these identifiers are registered to the SavoryView instance somehow (programatically or in Interface Builder)

• dequeueReusableHeader(Body)Cell(forPanelAt:): Like dequeueReusableCell(withIdentifier:for:) method for UITableView, these methods dequeue reusable cells for panel at certain index.

SavoryView renders its panels as collapsed or expanded based on its stateProvider property.

Actually [SavoryPanelState] type "conforms to" this protocol naturally. However, because swift hasn't supported an extension like below yet( may come soon according to apple/swift)

extension Array: SavoryStateProvider where Element == SavoryPanelState {} 

Savory provides a wrapper implementation as SimpleStateProvider and it requires a [SavoryPanelState] for initializing and then it acts just like a stored array from SavoryView's perspective.

For most circumstances, this is sufficient unless you want to provide some complex state managing feature.

Remember to call reloadData on SavoryView if you provided a custom implementation of SavoryStateProvider and it changes its state programatically

• Animation synchronization
• Custom Animation
• Find a way to test commit cc2bc43ad436dc4d9d4a1390e68688e54b44ae12
• @IBDesignable

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