#SwiftyJSON 中文介绍

SwiftyJSON makes it easy to deal with JSON data in Swift.

1. Why is the typical JSON handling in Swift NOT good
2. Requirements
3. Integration
4. Usage
   • Initialization
   • Subscript
   • Loop
   • Error
   • Optional getter
   • Non-optional getter
   • Setter
   • Raw object
   • Literal convertibles
5. Work with Alamofire

##Why is the typical JSON handling in Swift NOT good? Swift is very strict about types. But although explicit typing is good for saving us from mistakes, it becomes painful when dealing with JSON and other areas that are, by nature, implicit about types.

Take the Twitter API for example. Say we want to retrieve a user's "name" value of some tweet in Swift (according to Twitter's API https://dev.twitter.com/docs/api/1.1/get/statuses/home_timeline).

The code would look like this:

letjsonObject:AnyObject!=NSJSONSerialization.JSONObjectWithData(dataFromTwitter, options:NSJSONReadingOptions.MutableContainers, error:nil)iflet statusesArray = jsonObject as?NSArray{iflet aStatus =statusesArray[0]as?NSDictionary{iflet user =aStatus["user"]as?NSDictionary{iflet userName =user["name"]as?NSString{
//Finally We Got The Name
}}}}

It's not good.

Even if we use optional chaining, it would also cause a mess:

letjsonObject:AnyObject!=NSJSONSerialization.JSONObjectWithData(dataFromTwitter, options:NSJSONReadingOptions.MutableContainers, error:nil)iflet userName =(((jsonObject as?NSArray)?[0]as?NSDictionary)?["user"]as?NSDictionary)?["name"]{
//What A disaster above
}

An unreadable mess--for something that should really be simple!

With SwiftyJSON all you have to do is:

letjson=JSON(data: dataFromNetworking)iflet userName =json[0]["user"]["name"].string{
//Now you got your value
}

And don't worry about the Optional Wrapping thing. It's done for you automatically.

letjson=JSON(data: dataFromNetworking)iflet userName =json[999999]["wrong_key"]["wrong_name"].string{
//Calm down, take it easy, the ".string" property still produces the correct Optional String type with safety
}else{
//Print the error
println(json[999999]["wrong_key"]["wrong_name"])}

Requirements

• iOS 7.0+ / Mac OS X 10.9+
• Xcode 6.1

##Integration

####Carthage You can use Carthage to install SwiftyJSON by adding github "SwiftyJSON/SwiftyJSON" >= 2.1.2 to your Cartfile

####CocoaPods CocoaPods beta release now supports for Swift.

pod'SwiftyJSON','2.1.3'

Note that it needs you to install CocoaPods pre-released version, and requires your iOS deploy target >= 8.0:

[sudo] gem install cocoapods --pre

####Manually

To use this library in your project manually you may:

1. for Projects, just drag SwiftyJSON.swift to the project tree
2. for Workspaces, include the whole SwiftyJSON.xcodeproj (as suggested by @garnett)

Usage

####Initialization

letjson=JSON(data: dataFromNetworking)

letjson=JSON(jsonObject)

####Subscript

//With a int from JSON supposed to an Array
letname=json[0].double

//With a string from JSON supposed to an Dictionary
letname=json["name"].stringValue

//With an array like path to the element
letpath=[1,"list",2,"name"]letname=json[path].string //Just the same
letname=json[1]["list"][2]["name"].string

//With a literal array to the element
letname=json[1,"list",2,"name"].string //Just the same
letname=json[1]["list"][2]["name"].string

//With a Hard Way
letname=json[[1,"list",2,"name"]].string

####Loop

//If json is .Dictionary
for(key: String, subJson: JSON)in json {
//Do something you want
}

The first element is always String, even if the JSON's object is Array

//If json is .Array
//The `index` is 0..<json.count's string value
for(index: String, subJson: JSON)in json {
//Do something you want
}

####Error Use subscript to get/set value in Array or Dicitonary

• If json is an array, the app may crash with "index out-of-bounds."
• If json is a dictionary, it will get nil without the reason.
• If json is not an array or a dictionary, the app may crash with the wrong selector exception.

It will never happen in SwiftyJSON.

letjson=JSON(["name","age"])iflet name =json[999].string {
//Do something you want
}else{println(json[999].error) // "Array[999] is out of bounds"
}

letjson=JSON(["name":"Jack","age":25])iflet name =json["address"].string {
//Do something you want
}else{println(json["address"].error) // "Dictionary["address"] does not exist"
}

letjson=JSON(12345)iflet age =json[0].string {
//Do something you want
}else{println(json[0]) // "Array[0] failure, It is not an array"
println(json[0].error) // "Array[0] failure, It is not an array"
}iflet name =json["name"].string {
//Do something you want
}else{println(json["name"]) // "Dictionary[\"name"] failure, It is not an dictionary"
println(json["name"].error) // "Dictionary[\"name"] failure, It is not an dictionary"
}

####Optional getter

//NSNumber
iflet id =json["user"]["favourites_count"].number {
//Do something you want
}else{
//Print the error
println(json["user"]["favourites_count"].error)}

//String
iflet id =json["user"]["name"].string {
//Do something you want
}else{
//Print the error
println(json["user"]["name"])}

//Bool
iflet id =json["user"]["is_translator"].bool {
//Do something you want
}else{
//Print the error
println(json["user"]["is_translator"])}

//Int
iflet id =json["user"]["id"].int {
//Do something you want
}else{
//Print the error
println(json["user"]["id"])}...

####Non-optional getter Non-optional getter is named xxxValue

//If not a Number or nil, return 0
letid:Int=json["id"].intValue

//If not a String or nil, return ""
letname:String=json["name"].stringValue

//If not a Array or nil, return []
letlist:Array<JSON>=json["list"].arrayValue

//If not a Dictionary or nil, return [:]
letuser:Dictionary<String,JSON>=json["user"].dictionaryValue

####Setter

json["name"]=JSON("new-name")json[0]=JSON(1)

json["id"].int =1234567890json["coordinate"].double =8766.766json["name"].string ="Jack"
json.array =[1,2,3,4]
json.dictionary =["name":"Jack","age":25]

####Raw object

letjsonObject:AnyObject= json.object

if let jsonObject:AnyObject= json.rawValue

//convert the JSON to raw NSData
iflet data = json.rawData(){
//Do something you want
}

//convert the JSON to raw String
iflet string = json.rawString(){
//Do something you want
}

####Literal convertibles More info about the literal convertibles: Swift Literal Convertibles

//StringLiteralConvertible
letjson:JSON="I'm a json"

//IntegerLiteralConvertible
letjson:JSON=12345

//BooleanLiteralConvertible
letjson:JSON=true

//FloatLiteralConvertible
letjson:JSON=2.8765

//DictionaryLiteralConvertible
letjson:JSON=["I":"am","a":"json"]

//ArrayLiteralConvertible
letjson:JSON=["I","am","a","json"]

//NilLiteralConvertible
letjson:JSON=nil

//With subscript in array
varjson:JSON=[1,2,3]json[0]=100json[1]=200json[2]=300json[999]=300 //Don't worry, nothing will happen

//With subscript in dictionary
varjson:JSON=["name":"Jack","age":25]json["name"]="Mike"json["age"]="25" //It's OK to set String
json["address"]="L.A." // Add the "address": "L.A." in json

//Array & Dictionary
varjson:JSON=["name":"Jack","age":25,"list":["a","b","c",["what":"this"]]]json["list"][3]["what"]="that"json["list",3,"what"]="that"letpath=["list",3,"what"]json[path]="that"

##Work with Alamofire

SwiftyJSON nicely wraps the result of the Alamofire JSON response handler:

Alamofire.request(.GET, url, parameters: parameters).responseJSON{(req, res, json, error)inif(error !=nil){NSLog("Error: \(error)")println(req)println(res)}else{NSLog("Success: \(url)")varjson=JSON(json!)}}