Looping through embedded JSON arrays in Swift? - ios

Question

I'm trying to loop through an embedded JSON array and extract all the values to put in a local array. This is what the JSON looks like:
"welcome": {
"data": {
"tncUrl": ""
},
"items": [
{
"newUser": [
{
"stepConcept": false
},
{
"stepSafety": true
},
{
"stepFacilitator": true
},
{
"stepTransparency": true
}
],
"switcher": [
{
"stepConcept": true
},
{
"stepSafety": true
},
{
"stepFacilitator": true
},
{
"stepTransparency": true
}
]
}
]
}
I'm able to get to a point where I can see I'm retrieving values for "newUser", the problem is looping through those values and adding them to an array. I'm getting a EXC_BAD_INSTRUCTION error when doing so. This is the code I'm using to get those values:
func prepareArrayOfViews(userType: User)
{
if (welcomeJSON != nil)
{
let items : NSArray? = welcomeJSON!.value(forKey: "items") as? NSArray
if (items == nil)
{
listOfViews = ["stepConcept", "stepSafety", "stepFacilitator", "stepTransparency"]
maxPages = listOfViews.count
return
}
if (items != nil) {
if let newUser = (items?.value(forKey: "newUser") as? NSArray){
//Below is where the error "EXC_BAD_INSTRUCTION"
for key in (newUser as! NSDictionary).allKeys
{
if (((newUser as! NSDictionary).value(forKey: key as! String) as? Bool)!)
{
listOfViews.append(key as! String)
}
}
}
if (listOfViews.count == 0)
{
listOfViews = ["stepConcept", "stepSafety", "stepFacilitator", "stepTransparency"]
}
maxPages = listOfViews.count
}
}
}

Answer 1

I have changed your code to use native Swift structs. Since you are not handling errors or doing anything when your optional unwrapping doesn't work, I have also changed the unwrapping to guard statements.
Other than the serious problems with Swift coding practices, your issue was that you were trying to iterate through an array of dictionaries as a simple dictionary.
func prepareArrayOfViews(userType: User){
guard let welcomeJSON = welcomeJSON else {return}
guard let items = welcomeJSON["items"] as? [[String:Any]] else {
listOfViews = ["stepConcept", "stepSafety", "stepFacilitator", "stepTransparency"]
maxPages = listOfViews.count
return
}
for item in items {
if let newUser = item["newUser"] as? [[String:Any]] {
for embeddedDict in newUser {
for (key, value) in embeddedDict {
if let val = value as? Bool, val == true {
listOfViews.append(key)
}
}
}
} else if let switcher = item["switcher"] as? [[String:Any]]{
for embeddedDict in switcher {
for (key, value) in embeddedDict {
if let val = value as? Bool, val == true {
//do whatever you need to with the value
}
}
}
}
}
if (listOfViews.count == 0){
listOfViews = ["stepConcept", "stepSafety", "stepFacilitator", "stepTransparency"]
}
maxPages = listOfViews.count
}

Answer 2

Because
//here newUser is an NSArray
if let newUser = (items?.value(forKey: "newUser") as? NSArray){
//here newUser forced to NSDictionary
for key in (newUser as! NSDictionary).allKeys
try to change this part to
if let newUsers = (items?.value(forKey: "newUser") as? NSArray){
for newUser in newUsers
{
for key in (newUser as! NSDictionary).allKeys
{
if (((newUser as! NSDictionary).value(forKey: key as! String) as? Bool)!)
{
listOfViews.append(key as! String)
}
}
}
}