用android studio显示来自MySQL数据库的数据

我在一个项目上工作很简单,下面是我的代码(XML):

<?xml version="1.0" encoding="utf-8"?> <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.test.test.MainActivity"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Hello World!" android:id="@+id/tv" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintRight_toRightOf="parent" app:layout_constraintTop_toTopOf="parent" /> </android.support.constraint.ConstraintLayout> 

这是我在Kotlin的代码:

 package com.test.test import android.os.AsyncTask import android.support.v7.app.AppCompatActivity import android.os.Bundle import android.view.View import kotlinx.android.synthetic.main.activity_main.* import org.json.JSONObject import java.io.BufferedReader import java.io.InputStream import java.io.InputStreamReader import java.net.HttpURLConnection import java.net.URL import java.util.zip.CheckedInputStream class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) } fun GetSunset(view: View){ val url = "mywebsite/site.php" MyAsyncTask().execute(url) } inner class MyAsyncTask: AsyncTask<String, String, String>() { override fun onPreExecute(){ } override fun doInBackground(vararg p0: String?): String { try{ val url = URL(p0[0]) val urlConnect = url.openConnection() as HttpURLConnection urlConnect.connectTimeout=7000 var inString = ConvertStreamToString(urlConnect.inputStream) publishProgress(inString) }catch (ex:Exception){} return " " } override fun onProgressUpdate(vararg values: String?) { try{ // Here I don't know what I have to put ??? //tv.text = "Hello" tv.text = testtext }catch (ex:Exception){} } override fun onPostExecute(result: String?) { } } fun ConvertStreamToString(inputStream: InputStream):String{ val bufferReader= BufferedReader(InputStreamReader(inputStream)) var line:String var AllString:String="" try{ do { line = bufferReader.readLine() if (line != null) { AllString += line } }while (line!=null) inputStream.close() }catch (ex:Exception){} return AllString }} 

这是JSON文件:

 {"response":[{"Id_number":"5","job":"Nurse"}]} 

我想要的是提取“护士”,也就是说我想testtext = "Nurse" ,我精确的我所有是好的唯一的问题是功能override fun onProgressUpdate(vararg values: String?)在MainActivity

非常感谢您的帮助,因为我尝试了很多东西,但每次都不起作用,我不明白为什么!