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iOS Build a Playlist Browser with Swift Building the Music Library and Playlist Models Struct Initialization

Jeff Lange
Jeff Lange
4,791 Points

Lots of errors in my init method: 'AnyObject?' is not convertible to 'String!'

Any time I use the playlistDictionary in my Playlist init in my Playlist.swift file, I get the error: 'AnyObject?' is not convertible to 'String!'

This happens on the title, description, iconName, largeIconName, artists, and colorsDictionary line.

//
//  Playlist.swift
//  Algorhythm01
//
//  Created by Jeff Lange on 4/11/15.
//  Copyright (c) 2015 Jeff Lange. All rights reserved.
//

import Foundation
import UIKit

struct Playlist {

    var title: String?
    var description: String?
    var icon: UIImage?
    var largeIcon: UIImage?
    var artists: [String] = []
    var backgroundColor: UIColor = UIColor.clearColor()

    init(index: Int) {
        let musicLibrary = MusicLibrary().library
        let playlistDictionary = musicLibrary[index]

        title = playlistDictionary["title"] as String!
        description = playlistDictionary["description"] as String!

        let iconName = playlistDictionary["icon"] as String!
        icon = UIImage(named: iconName)

        let largeIconName = playlistDictionary["largeIcon"] as String!
        largeIcon = UIImage(named: largeIconName)

        artists += playlistDictionary["artists"] as [String]

        let colorsDictionary = playlistDictionary["backgroundColor"] as [String: CGFloat]
        backgroundColor = rgbColorFromDictionary(colorsDictionary)

    }

    func rgbColorFromDictionary(colorDictionary: [String: CGFloat]) -> UIColor {

        let red = colorDictionary["red"]!
        let green = colorDictionary["green"]!
        let blue = colorDictionary["blue"]!
        let alpha = colorDictionary["alpha"]!

        return UIColor(red: red/255.0, green: green/255.0, blue: blue/255.0, alpha: alpha)

    }
}

Add ! after as... this had to be done after the most recent update to swift. eg. title = playlistDictionary["title"] as! String!

Jeff Lange
Jeff Lange
4,791 Points

Thanks, Andre! I thought I was going crazy trying to track down what I did wrong.

2 Answers

Ethan Lowry
PLUS
Ethan Lowry
Courses Plus Student 7,323 Points

You may need to place the ! after e.g. playlistDictionary["title"] instead of after the String! casting. My swift is a little rusty but at first glance it looks to me like when you access your dictionary you're getting an AnyObject optional back, then trying to cast it as a String, which I believe can't be done with an optional. If you unwrap the dictionary contents first with e.g. !, then maybe you'll be able to cast them to string.

Hope that helps.

Ian Stewart
Ian Stewart
4,255 Points

Hi,

I'm using Xcode 6.0 and this seems to give no errors but I am not sure why?

struct Playlist {

    var title: String?
    var description: String?
    var icon: UIImage?
    var largeIcon: UIImage?
    var artists: [String] = []
    var backgroundColor: UIColor = UIColor.clearColor()

    init(index: Int) {
        let musicLibrary = MusicLibrary().library
        let playlistDictionary = musicLibrary[index]

        title = playlistDictionary["title"]! as? String
        description = playlistDictionary["description"]! as? String

        let iconName = playlistDictionary["icon"]! as? String
        icon = UIImage (named: iconName!)

        let largeIconName = playlistDictionary["largeIcon"]! as? String
        largeIcon = UIImage (named: largeIconName!)

        artists += playlistDictionary["artists"]! as [String]

    }  
}

This was more trial and error than anything though when it comes to the ! and ? uses!

Thanks

Ian