Android Kotlin解析Json文件(Gson)

MainActivity.kt

package com.example.fredric.sendrequestwithokhttp

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import android.view.View
import android.widget.Button
import android.widget.TextView
import com.google.gson.Gson
import com.google.gson.reflect.TypeToken
import okhttp3.OkHttpClient
import okhttp3.Request
import org.json.JSONArray
import org.xml.sax.InputSource
import org.xmlpull.v1.XmlPullParser
import org.xmlpull.v1.XmlPullParserFactory
import java.io.StringReader
import javax.xml.parsers.SAXParserFactory

inline fun <reified T> KTypeToken() = object : TypeToken<T>() {} .type

class MainActivity : AppCompatActivity(), View.OnClickListener{


    var responseText: TextView? = null


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        var sendRequest = findViewById<Button>(R.id.send_request)
        responseText = findViewById<TextView>(R.id.response_text)

        sendRequest.setOnClickListener(this)
    }

    override fun onClick(v: View?) {
        if(v?.id == R.id.send_request) {
            sendRequestWithOkHttp()
        }
    }


    fun showResponse(responseData: String?) {
        runOnUiThread(object: Runnable{
            override fun run() {
                responseText?.setText(responseData)
            }
        })
    }

    fun parseXMLWithPull(responseData:String) {
        try {
            var factory = XmlPullParserFactory.newInstance()
            var pullParser = factory.newPullParser()
            pullParser.setInput(StringReader(responseData))
            var eventType = pullParser.eventType
            var id = ""
            var name = ""
            var version = ""

            while (eventType != XmlPullParser.END_DOCUMENT) {
                var nodeName = pullParser.name
                when(eventType) {
                    XmlPullParser.START_TAG -> {
                        if("id".equals(nodeName)) {
                            id = pullParser.nextText()
                        }else if("name".equals(nodeName)) {
                            name = pullParser.nextText()
                        }else if("version".equals(nodeName)) {
                            version = pullParser.nextText()
                        }
                    }

                    XmlPullParser.END_TAG -> {
                        if("app".equals(nodeName)) {
                            Log.d("MainActivity","id is: "+id)
                            Log.d("MainActivity","name is: "+name)
                            Log.d("MainActivity","version is: "+version)
                        }
                    }

                    else -> {

                    }
                }

                eventType = pullParser.next()
            }
        }catch (ex: Exception) {
            ex.printStackTrace()
        }
    }


    fun parseXMLWithSax(xmlData: String) {
        try {
            var factory = SAXParserFactory.newInstance()
            var xmlReader = factory.newSAXParser().xmlReader
            var handler = ContentHandler()
            xmlReader.contentHandler = handler
            xmlReader.parse(InputSource(StringReader(xmlData)))
        }catch (ex: Exception) {
            ex.printStackTrace()
        }
    }


    fun parseJsonWithJsonObject(jsonData: String) {
        try {
            var jsonArray = JSONArray(jsonData)

            for(i in 0..jsonArray.length()-1) {
                var jsonObject = jsonArray.getJSONObject(i)
                var id = jsonObject.getString("id")
                var name = jsonObject.getString("name")
                var version = jsonObject.getString("version")
                Log.d("MainActvity","id is: "+id)
                Log.d("MainActivity","name is: "+ name)
                Log.d("MainActivity","version is: "+version)
            }
        }catch (ex: Exception) {
            ex.printStackTrace()
        }
    }


    fun parseJsonWithGson(jsonData: String) {
        var gson = Gson()
        var appList = gson.fromJson<List<App>>(jsonData, KTypeToken<List<App>>())
        for(app in appList) {

            Log.d("MainActivity","id is: "+app.id)
            Log.d("MainActivity","name is: "+app.name)
            Log.d("MainActivity","version is: "+app.version)
        }
    }

    fun sendRequestWithOkHttp() {
        Thread(object: Runnable{
            override fun run() {
                try {
                    var client = OkHttpClient()
                    var request = Request.Builder().
                            url("http://192.168.0.102/get_data.json").
                            build()
                    var response = client.newCall(request).execute()
                    var responseData = response.body().string()

                    showResponse(responseData)
//                    parseXMLWithPull(responseData)
//                    parseXMLWithSax(responseData)
//                    parseJsonWithJsonObject(responseData)
                    parseJsonWithGson(responseData)
                }catch (ex: Exception) {
                    ex.printStackTrace()
                }
            }
        }).start()
    }
}

ContentHandler.kt

package com.example.fredric.sendrequestwithokhttp

import android.util.Log
import org.xml.sax.Attributes
import org.xml.sax.SAXException
import org.xml.sax.helpers.DefaultHandler

class ContentHandler : DefaultHandler() {

    var nodeName: String? = null
    var id: StringBuilder? = null
    var name: StringBuilder? = null
    var version: StringBuilder? = null


    @Throws(SAXException::class)
    override fun startDocument() {
        id = StringBuilder()
        name = StringBuilder()
        version = StringBuilder()
    }


    @Throws(SAXException::class)
    override fun endDocument() {
        super.endDocument()
    }


    @Throws(SAXException::class)
    override fun startElement(uri: String, localName: String, qName: String, attributes: Attributes) {
        nodeName = localName
    }


    @Throws(SAXException::class)
    override fun characters(ch: CharArray, start: Int, length: Int) {
        if("id".equals(nodeName)) {
            id?.append(ch,start,length)
        }else if("name".equals(nodeName)) {
            name?.append(ch,start,length)
        }else if("version".equals(nodeName)) {
            version?.append(ch, start, length)
        }
    }

    @Throws(SAXException::class)
    override fun endElement(uri: String, localName: String, qName: String) {
        if("app".equals(localName)) {
            Log.d("ContentHandler","id is :" + id?.toString()?.trim())
            Log.d("ContentHandler","name is :" + name?.toString()?.trim())
            Log.d("ContentHandler","version is :" + version?.toString()?.trim())

            id?.setLength(0)
            name?.setLength(0)
            version?.setLength(0)
        }
    }

}

App.kt

package com.example.fredric.sendrequestwithokhttp

data class App(
        var id: String?,
        var name: String?,
        var version: String?
)

程序运行效果，

Screen Shot 2018-07-24 at 6.38.15 AM.png