Pull mode to parse xml files

Adjust the receiving protocol (the use of https protocol can be ignored)

Because I simply built a web server with apache, which only supports the http protocol, so the following operations should be performed to ensure that the data can be received.

• Created a new configuration file network_config.xml under the xml folder of res

<?xml version="1.0" encoding="utf-8" ?>
<network-security-config>
    <base-config cleartextTrafficPermitted="true">
        <trust-anchors>
            <certificates src="system"/>
        </trust-anchors>
    </base-config>
</network-security-config>

• Make the following changes in the AndroidManifest.xml configuration file (bold)

 

<application
    android:allowBackup="true"
    android:dataExtractionRules="@xml/data_extraction_rules"
    android:fullBackupContent="@xml/backup_rules"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/Theme.OkHttp"
    android:networkSecurityConfig="@xml/network_config"
    tools:targetApi="31">

Write the layout file

Only one button and one textview are defined here.

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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=".MainActivity">

    <Button
        android:id="@+id/button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="open"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"/>
    <TextView
        android:id="@+id/tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text=" "
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

 

 access network

Here I choose to use OkHttp to access the network, write a method, and call this method when the button is clicked.

    fun HttpRquest() {
        thread {
            try {
                val okhttpclient = OkHttpClient()
                val request = okhttp3.Request.Builder()
                    .url("http://43.137.44.141/get_data.xml")
                    .build()
                val initcontent = okhttpclient.newCall(request).execute()
                val content = initcontent.body?.string()
                if (content != null) {
                    //调用解析方法，下文中写了。
                    parseXML(content)
                }
            } catch (e: Exception) {
                e.printStackTrace()
            }
        }
    }

Analytical data

Data format display:

//要解析的数据格式
<apps>
    <app>
        <id>1</id>
        <name>Google Maps</name>
        <version>1.0</version>
    </app>
    <app>
        <id>2</id>
        <name>Chome</name>
        <version>2.1</version>
    </app>
    <app>
        <id>3</id>
        <name>Google Play</name>
        <version>2.3</version>
    </app>
</apps>

A method for parsing data is defined, and the parsed data is filled into the textview. 

fun parseXML(Data: String) {
         runOnUiThread {
             val content=StringBuilder()
             try {
                 val factory = XmlPullParserFactory.newInstance()
                 val pullParser = factory.newPullParser()
                 pullParser.setInput(StringReader(Data))
                 var eventType = pullParser.eventType
                 var id = ""
                 var name = ""
                 var version = ""
                 while (eventType != XmlPullParser.END_DOCUMENT){
                     val node=pullParser.name
                     when(eventType){
                         XmlPullParser.START_TAG->{
                             when(node){
                                 "id"->id=pullParser.nextText()
                                 "name"->name=pullParser.nextText()
                                 "version"->version=pullParser.nextText()
                             }
                         }
                         XmlPullParser.END_TAG->{
                             if ("app"==node){
                                 content.append("id:$id\tname:$name\tversion:$version\n")
                                 Log.d("information","id:$id\tname:$name\tversion:$version")
                             }
                         }
                     }
                     eventType=pullParser.next()
                 }
                 binding.tv.text=content.toString()
             }catch (e:Exception){
                 e.printStackTrace()
             }
         }

    }

 Attach the total code for easy copying

package com.example.okhttp

import android.os.Bundle
import android.util.Log
import androidx.appcompat.app.AppCompatActivity
import com.example.okhttp.databinding.ActivityMainBinding
import okhttp3.OkHttpClient
import org.xmlpull.v1.XmlPullParser
import org.xmlpull.v1.XmlPullParserFactory
import java.io.StringReader
import kotlin.concurrent.thread


class MainActivity : AppCompatActivity() {
    lateinit var binding: ActivityMainBinding
    override fun onCreate(savedInstanceState: Bundle?) {
        binding = ActivityMainBinding.inflate(layoutInflater)
        super.onCreate(savedInstanceState)
        setContentView(binding.root)
        binding.button.setOnClickListener {
            HttpRquest()
        }
    }

    fun HttpRquest() {
        thread {
            try {
                val okhttpclient = OkHttpClient()
                val request = okhttp3.Request.Builder()
                    .url("http://43.137.44.141/get_data.xml")
                    .build()
                val initcontent = okhttpclient.newCall(request).execute()
                val content = initcontent.body?.string()
                if (content != null) {
                    parseXML(content)
                    
                }
            } catch (e: Exception) {
                e.printStackTrace()
            }
        }
    }

    fun parseXML(Data: String) {
         runOnUiThread {
             val content=StringBuilder()
             try {
                 val factory = XmlPullParserFactory.newInstance()
                 val pullParser = factory.newPullParser()
                 pullParser.setInput(StringReader(Data))
                 var eventType = pullParser.eventType
                 var id = ""
                 var name = ""
                 var version = ""
                 while (eventType != XmlPullParser.END_DOCUMENT){
                     val node=pullParser.name
                     when(eventType){
                         XmlPullParser.START_TAG->{
                             when(node){
                                 "id"->id=pullParser.nextText()
                                 "name"->name=pullParser.nextText()
                                 "version"->version=pullParser.nextText()
                             }
                         }
                         XmlPullParser.END_TAG->{
                             if ("app"==node){
                                 content.append("id:$id\tname:$name\tversion:$version\n")
                                 Log.d("information","id:$id\tname:$name\tversion:$version")
                             }
                         }
                     }
                     eventType=pullParser.next()
                 }
                 binding.tv.text=content.toString()
             }catch (e:Exception){
                 e.printStackTrace()
             }
         }

    }
}

attached renderings