SwiftyJSON keeps returning empty objects - ios

Question

I am new to SwiftyJSON, and I'm having some trouble with it. I can get it to return the entire JSON file as a string, but the moment I try to parse it, I keep getting empty variables back, and I'm not sure what I'm doing wrong.
This is the formatting of my JSON file:
[
{
"entryID": 1,
"from": "String",
"to": "String",
"value": "String"
},
{
...
},
...
]
And this is roughly what I want to do with it (in quite inelegant code, I do apologise, I'm new to Swift):
for entry: JSON in indexJSON.arrayValue {
var vEntryID: Int
var vFrom: String
var vTo: String
var vValue: String
for (dictKey: String, dictVal: JSON) in entry.dictionaryValue {
if(dictKey=="entryID") {vEntryID = dictVal.intValue}
if(dictKey=="from") {vFrom = dictVal.stringValue}
if(dictKey=="to") {vTo = dictVal.stringValue}
if(dictKey=="value") {vValue = dictVal.stringValue}
}
someSwiftObject[vEntryID]["from"] = vFrom
someSwiftObject[vEntryID]["to"] = vTo
someSwiftObject[vEntryID]["value"] = vValue
}
However, this block never executes at all, because indexJSON.arrayValue is always empty.
When I try to run the following, it correctly prints the complete file contents to the console:
let indexJSON = JSON(content!)
println(indexJSON.stringValue)
But when I try to go deeper, to fetch any element, it returns nothing:
if(indexJSON.arrayValue.isEmpty==true) {println("indexJSON.arrayValue is Empty")}
if(indexJSON[0].arrayValue.isEmpty==true) {println("indexJSON[0].arrayValue is Empty")}
if(indexJSON[0].dictionaryValue.isEmpty==true) {println("indexJSON[0].dictionaryValue is Empty")}
if(indexJSON[0]["entryID"]==nil) {println("indexJSON[0][\"entryID\"].stringValue is Empty")}
Output:
indexJSON.arrayValue is Empty
indexJSON[0].arrayValue is Empty
indexJSON[0].dictionaryValue is Empty
indexJSON[0]["entryID"].stringValue is Empty
I'd be grateful for any help! What am I doing wrong?

Answer 1

I checked SwiftyJSON source code and I think I know where the problem is.
I suppose that you are using String to initialize the JSON object like this
let s = "{\"entryID\": 1,\"from\": \"String\",\"to\": \"String\",\"value\": \"String\"}"
let j = JSON(s)
In this case the JSON object is actuall given a type "String", not Array. That's why it's not iterable and its arrayValue is empty.
To do what you want to do, you need to initialize it with an Array object:
let arr = [
[
"entryID":1,
"from":"String",
"to":"String",
"value":"String",
]
]
let j2 = JSON(arr)
Now j2 is an array JSON object and iterable.
SwiftyJSON can only be initialized with NSData and object. So if you want to initialize it with a String you need to do this:
if let data = s.dataUsingEncoding(NSUTF8StringEncoding) {
let j = JSON(data:data)
println(j)
}

Answer 2

first of all, make sure the format of your json string is correct. in your question, your json string is a array, just format the string like this(the content is from my code):
let jsonStr = "[{\"name\": \"hangge\", \"age\": 100, \"phones\": [{\"name\": \"公司\",\"number\": \"123456\"}, {\"name\": \"家庭\",\"number\": \"001\"}]}, {\"name\": \"big boss\",\"age\": 1,\"phones\": [{ \"name\": \"公司\",\"number\": \"111111\"}]}]"
then you can use SwityJson to get the array object, like this:
let strData = jsonStr.data(using: String.Encoding.utf8, allowLossyConversion: false)
let json = JSON(data: strData!)
for object in json.arrayValue {
let name = object["name"].string
}

Answer 3

Take a look at the documentation here: https://github.com/lingoer/SwiftyJSON#loop
You are iterating it incorrectly. You should be iterating over the array with a for loop like this:
for (index: String, subJson: JSON) in json {
//Do something you want
}