runtime lldb crash - optional / unwrapping issue with data model - swift

Question

I just finished converting this project to Swift 2 and had a ton of optionals to fix. So naturally there were bound to be some runtime issues. Console is giving the usual optional error message. I have a data model and other classes though so I'm having difficulty sourcing the problem/s. So far I think there is only this one issue though. Could you please suggest proper optional declaration / unwrapping. I know what they mean but since I'm fairly green I need to be shown what to fix even though I know the definition of optionals. I realize the images in the navigation window are optionals. They definitely exist so they should be unwrapped. So is there a problem with nickname or SpaceObject class?
SpaceObject.swift
class SpaceObject: NSObject {
var name: String?
var gravitationalForce: Float?
var diameter: Float?
var yearLength: Float?
var dayLength: Float?
var temperature: Float?
var numberOfMoons: Int?
var nickname: String?
var interestingFact: String?
var spaceImage: UIImage?
override init() {
}
init(initWithData data:NSDictionary, andImage image:UIImage) {
if (data[PLANET_NAME] != nil) { self.name = String(format: data[PLANET_NAME] as! NSString as String) }
if (data[PLANET_GRAVITY] != nil) { self.gravitationalForce = Float(data[PLANET_GRAVITY] as! NSNumber) }
if (data[PLANET_DIAMETER] != nil) { self.diameter = Float(data[PLANET_DIAMETER] as! NSNumber) }
if (data[PLANET_YEAR_LENGTH] != nil) { self.yearLength = Float(data[PLANET_YEAR_LENGTH] as! NSNumber) }
if (data[PLANET_DAY_LENGTH] != nil) { self.dayLength = Float(data[PLANET_DAY_LENGTH] as! NSNumber) }
if (data[PLANET_TEMPERATURE] != nil) { self.temperature = Float(data[PLANET_TEMPERATURE] as! NSNumber) }
if (data[PLANET_NUMBER_OF_MOONS] != nil) { self.numberOfMoons = Int(data[PLANET_NUMBER_OF_MOONS] as! NSNumber) }
if (data[PLANET_NICKNAME] != nil) { self.nickname = String(format: data[PLANET_NICKNAME] as! NSString as String) }
if (data[PLANET_INTERESTING_FACT] != nil) { self.interestingFact = String(format: data[PLANET_INTERESTING_FACT] as! NSString as String) }
self.spaceImage = image
}
}
SpaceDataViewController.swift
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("DataCell", forIndexPath: indexPath) as UITableViewCell
switch indexPath.row {
case 0:
cell.textLabel!.text = "Nickname:"
if let nickname = self.spaceObject?.nickname {
cell.detailTextLabel!.text = "\(nickname)"
}
case 1:
cell.textLabel!.text = "Diameter (km):"
if let diameter = self.spaceObject?.diameter {
cell.detailTextLabel!.text = "\(diameter)"
}
case 2:
cell.textLabel!.text = "Gravitational Force:"
if let gravitationalForce = self.spaceObject?.gravitationalForce {
cell.detailTextLabel!.text = "\(gravitationalForce)"
}
case 3:
cell.textLabel!.text = "Length of a Year (in days):"
if let yearLength = self.spaceObject?.yearLength {
cell.detailTextLabel!.text = "\(yearLength)"
}
case 4:
cell.textLabel!.text = "Length of a Day (in hours):"
if let dayLength = self.spaceObject?.dayLength {
cell.detailTextLabel!.text = "\(dayLength)"
}
case 5:
cell.textLabel!.text = "Temperature (in celsius):"
if let temperature = self.spaceObject?.temperature {
cell.detailTextLabel!.text = "\(temperature)"
}
case 6:
cell.textLabel!.text = "Number of Moons:"
if let numberOfMoons = self.spaceObject?.numberOfMoons {
cell.detailTextLabel!.text = "\(numberOfMoons)"
}
case 7:
cell.textLabel!.text = "Interesting Fact:"
if let interestingFact = self.spaceObject?.interestingFact {
cell.detailTextLabel!.text = "\(interestingFact)"
}
default: break
}
return cell
OuterSpaceTableViewController.swift
override func viewDidLoad() {
super.viewDidLoad()
for planetData in AstronomicalData.allKnownPlanets() {
let imageName = "\(planetData[PLANET_NAME]).jpg"
let planet = SpaceObject(initWithData: planetData as! NSDictionary, andImage: UIImage(named: imageName)!) // Mercury.jpg is an optional
self.planets += [planet]
}
if let spaceList = self.userDefaults.arrayForKey(ADDED_SPACE_OBJECTS_KEY) {
for spaceObjectItem in spaceList {
self.addedSpaceObjects += [self.spaceObjectForDictionary(spaceObjectItem)]
}
}
}
Swift-Strings-Extension.swift
extension String {
// Convert string to floats.
func toFloat() -> Float? {
return (self as NSString).floatValue
}
}

Answer 1

Solution to the error that you have posted is to unwrap the planet name string you fetch from the dictionary. Since its an optional, its returning the value as "Optional(Mercury)". So when you don't unwrap, the image name gets formed as "Optional(Mercury).jpg" which will obviously not be available in your resources folder.
Example:
for planetData in AstronomicalData.allKnownPlanets {
if let planetName = planetData[PLANET_NAME] as! String {
let imageName = "\(planetName).jpg" //Now it will be Mercury.jpg
}
//...
}
If you find more errors after this, they should be dealt on case by case basis.