SLComposable Protocol—Easy to use protocol for creation and presentation of SLComposeViewControllers

SLComposable.swift

//
//  SLComposable.swift
//  SocialFrameworkRef
//
//  Created by Stuart Breckenridge on 24/05/2016.
//  Copyright © 2016 Stuart Breckenridge. All rights reserved.
//

import Foundation
import Social

/**
 Social Networks available on iOS. The `rawValue` for the cases in this enum are identical to the `SLServiceType` constants.
 
 - Facebook:     Facebook.
 - Twitter:      Twitter.
 - SinaWeibo:    Sina Weibo.
 - TencentWeibo: Tencent Weibo.
 */
public enum SLComposableServiceType:String, CustomStringConvertible
{
    case Facebook = "com.apple.social.facebook"
    case Twitter = "com.apple.social.twitter"
    case SinaWeibo = "com.apple.social.sinaweibo"
    case TencentWeibo = "com.apple.social.tencentweibo"
    
    public var description: String {
        switch  self {
        case .Twitter:
            return "Twitter"
        case .Facebook:
            return "Facebook"
        case .SinaWeibo:
            return "Sina Weibo"
        case .TencentWeibo:
            return "Tencent Weibo"
        }
    }
}


/**
 *  The SLComposable protocol defines one method that allows for easy creation and presentation of `SLComposeViewController`s for all iOS supported Social Networks.
 */
public protocol SLComposable {
    /**
     This method will check that the user can post to the specified social network, and if they can it will present an `SLComposeViewController` populated with text, image, and URL if provided. If posting is not available, a UIAlertController is presented.
     
     - parameter text:    The initial text of the post. Optional.
     - parameter image:   An image to append. Optional.
     - parameter url:     An URL to append. Optional.
     - parameter network: The Social Network to use. See `SLComposableServiceType`.
     
     - seealso: `SLComposableServiceType`
     */
    func composePost(text text:String?, image:UIImage?, url:NSURL?, network: SLComposableServiceType)
}

/**
 *  `UIViewController` implementation of the `SLComposable` protocol.
 */
extension UIViewController:SLComposable
{
    public func composePost(text text:String?, image:UIImage?, url:NSURL?, network: SLComposableServiceType)
    {
        // If posting to the specified social network is not available, present a UIAlertController.
        guard SLComposeViewController.isAvailableForServiceType(network.rawValue) == true else
        {
            let alert = UIAlertController(title: "Error", message: "Posting to \(network.description) is not available. Have you added an account in Settings?", preferredStyle: .Alert)
            alert.addAction(UIAlertAction(title: "Dismiss", style: .Default, handler: nil))
            presentViewController(alert, animated: true, completion: nil)
            
            return
        }
        
        let socialController = SLComposeViewController(forServiceType: network.rawValue)
        
        socialController.completionHandler = {(result:SLComposeViewControllerResult) in
            switch result {
            case .Done:
                print("SLComposeViewController: Done")
            case .Cancelled:
                print("SLComposeViewController: Cancelled")
            }
        }
        
        if text != nil{
            socialController.setInitialText(text!)
        }
        
        if image != nil {
           socialController.addImage(image!)
        }
        
        if url != nil {
            socialController.addURL(url!)
        }
        
        // Present the SLComposeViewController.
        presentViewController(socialController, animated: true, completion: nil)
    }
}