SwiftyJSON 中文介绍

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

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:

let JSONObject: AnyObject? = NSJSONSerialization.JSONObjectWithData(data, options: nil, error: nil)

if let statusesArray = JSONObject as? [AnyObject],

   let status = statusesArray[0] as? [String: AnyObject],

   let user = status["user"] as? [String: AnyObject],

   let username = user["name"] as? String {

    // Finally we got the username

}

It's not good.

Even if we use optional chaining, it would be messy:

let JSONObject: AnyObject? = NSJSONSerialization.JSONObjectWithData(data, options: nil, error: nil)

if let username = (((JSONObject as? [AnyObject])?[0] as? [String: AnyObject])?["user"] as? [String: AnyObject])?["name"] as? String {

    // What a disaster

}

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

With SwiftyJSON all you have to do is:

let json = JSON(data: dataFromNetworking)

if let 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.

let json = JSON(data: dataFromNetworking)

if let 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

CocoaPods (iOS 8+, OS X 10.9+)

You can use Cocoapods to install SwiftyJSONby adding it to your Podfile:

platform :ios, '8.0'

use_frameworks!

target 'MyApp' do

    pod 'SwiftyJSON', '~> 2.2.0'

end

Note that it needs you to install CocoaPods 36 version, and requires your iOS deploy target >= 8.0:

Carthage (iOS 8+, OS X 10.9+)

You can use Carthage to install SwiftyJSON by adding it to your Cartfile:

github "SwiftyJSON/SwiftyJSON" >= 2.2.0

Manually (iOS 7+, OS X 10.9+)

To use this library in your project manually you may:

for Projects, just drag SwiftyJSON.swift to the project tree
for Workspaces, include the whole SwiftyJSON.xcodeproj

Usage

Initialization

import SwiftyJSON

let json = JSON(data: dataFromNetworking)

let json = JSON(jsonObject)

if let dataFromString = jsonString.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false) {

    let json = JSON(data: dataFromString)

}

Subscript

//Getting a double from a JSON Array

let name = json[0].double

//Getting a string from a JSON Dictionary

let name = json["name"].stringValue

//Getting a string using a path to the element

let path = [1,"list",2,"name"]

let name = json[path].string

//Just the same

let name = json[1]["list"][2]["name"].string

//Alternatively

let name = json[1,"list",2,"name"].string

//With a hard way

let name = json[].string

//With a custom way

let keys:[SubscriptType] = [1,"list",2,"name"]

let name = json[keys].string

Loop

//If json is .Dictionary

for (key: String, subJson: JSON) in json {

   //Do something you want

}

The first element is always a String, even if the JSON is an 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 a subscript to get/set a value in an Array or Dictionary

If the json is:

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

It will never happen in SwiftyJSON.

let json = JSON(["name", "age"])

if let name = json[999].string {

    //Do something you want

} else {

    println(json[999].error) // "Array[999] is out of bounds"

}

let json = JSON(["name":"Jack", "age": 25])

if let name = json["address"].string {

    //Do something you want

} else {

    println(json["address"].error) // "Dictionary["address"] does not exist"

}

let json = JSON(12345)

if let 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"

}

if let 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

if let id = json["user"]["favourites_count"].number {

   //Do something you want

} else {

   //Print the error

   println(json["user"]["favourites_count"].error)

}

//String

if let id = json["user"]["name"].string {

   //Do something you want

} else {

   //Print the error

   println(json["user"]["name"])

}

//Bool

if let id = json["user"]["is_translator"].bool {

   //Do something you want

} else {

   //Print the error

   println(json["user"]["is_translator"])

}

//Int

if let 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

let id: Int = json["id"].intValue

//If not a String or nil, return ""

let name: String = json["name"].stringValue

//If not a Array or nil, return []

let list: Array<JSON> = json["list"].arrayValue

//If not a Dictionary or nil, return [:]

let user: Dictionary<String, JSON> = json["user"].dictionaryValue

Setter

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

json[0] = JSON(1)

json["id"].int =  1234567890

json["coordinate"].double =  8766.766

json["name"].string =  "Jack"

json.arrayObject = [1,2,3,4]

json.dictionary = ["name":"Jack", "age":25]

Raw object

let jsonObject: AnyObject = json.object

if let jsonObject: AnyObject = json.rawValue

//convert the JSON to raw NSData

if let data = json.rawData() {

    //Do something you want

}

//convert the JSON to a raw String

if let string = json.rawString() {

    //Do something you want

}

Literal convertibles

For more info about literal convertibles: Swift Literal Convertibles

//StringLiteralConvertible

let json: JSON = "I'm a json"

//IntegerLiteralConvertible

let json: JSON =  12345

//BooleanLiteralConvertible

let json: JSON =  true

//FloatLiteralConvertible

let json: JSON =  2.8765

//DictionaryLiteralConvertible

let json: JSON =  ["I":"am", "a":"json"]

//ArrayLiteralConvertible

let json: JSON =  ["I", "am", "a", "json"]

//NilLiteralConvertible

let json: JSON =  nil

//With subscript in array

var json: JSON =  [1,2,3]

json[0] = 100

json[1] = 200

json[2] = 300

json[999] = 300 //Don't worry, nothing will happen

//With subscript in dictionary

var json: 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

var json: JSON =  ["name": "Jack", "age": 25, "list": ["a", "b", "c", ["what": "this"]]]

json["list"][3]["what"] = "that"

json["list",3,"what"] = "that"

let path = ["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) in

    if(error != nil) {

      NSLog("Error: \(error)")

      println(req)

      println(res)

    }

    else {

      NSLog("Success: \(url)")

      var json = JSON(json!)

    }

  }

https://github.com/SwiftyJSON/SwiftyJSON