srcminiXML文档通常用于在Internet上共享数据。以XML格式提供的数据能够经常更新, 并且解析它们是基于网络的应用程序的常见任务。
在Android中, 有三种类型的XML解析器可以解析XML数据并在android应用程序中读取它们, 它们是：
- DOM解析器
- SAX解析器
- XMLPullParser
Android DOM（文档对象模型）解析器使用基于对象的方法来创建和解析android应用程序中的XML文件。 DOM解析器将XML文件加载到内存中以解析XML文档。由于这个原因, 它消耗更多的内存。
使用DOM解析器进行XML解析的示例
在此示例中, 我们解析XML数据并将其显示在ListView中。
activity_main.xml
在activity_main.xml布局中添加ListView。
<?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="example.srcmini02.com.kotlinxmlparsingusingdomparser.MainActivity">
<ListView
android:id="@+id/listView"
android:layout_width="match_parent"
android:layout_height="match_parent">
</ListView>
</android.support.constraint.ConstraintLayout>empdetail.xml
在资产目录中创建XML文档empdetail.xml, 以使用DOM解析器解析数据。
<?xml version="1.0" encoding="utf-8"?>
<records>
<employee>
<name>Sachin Kumar</name>
<salary>50000</salary>
<designation>Developer</designation>
</employee>
<employee>
<name>Rahul Kumar</name>
<salary>60000</salary>
<designation>Team Leader</designation>
</employee>
<employee>
<name>John Mike</name>
<salary>70000</salary>
<designation>Manager</designation>
</employee>
<employee>
<name>Ajay Kumar</name>
<salary>45000</salary>
<designation>Developer</designation>
</employee>
<employee>
<name>Toni Nayer</name>
<salary>55000</salary>
<designation>Marketing</designation>
</employee>
<employee>
<name>Mr Bony</name>
<salary>42000</salary>
<designation>Sales</designation>
</employee>
<employee>
<name>Raj Kumar</name>
<salary>30000</salary>
<designation>Production</designation>
</employee>
<employee>
<name>Rahul Kumar</name>
<salary>60000</salary>
<designation>Team Leader</designation>
</employee>
<employee>
<name>John Mike</name>
<salary>70000</salary>
<designation>Manager</designation>
</employee>
<employee>
<name>Sachin Kumar</name>
<salary>50000</salary>
<designation>Developer</designation>
</employee>
<employee>
<name>Rahul Kumar</name>
<salary>60000</salary>
<designation>Team Leader</designation>
</employee>
<employee>
<name>John Mike</name>
<salary>70000</salary>
<designation>Manager</designation>
</employee>
</records>custom_list.xml
创建一个自定义布局以将数据列表显示到ListView中。
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="vertical">
<TextView
android:id="@+id/name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="name"
android:textStyle="bold"
android:layout_marginLeft="15dp"
android:layout_marginStart="15dp"
android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />
<TextView
android:id="@+id/salary"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="salary"
android:layout_marginLeft="15dp"
android:layout_marginStart="15dp"
android:layout_marginTop="5dp"
android:textSize="16sp"/>
<TextView
android:id="@+id/designation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="designation"
android:layout_marginLeft="15dp"
android:layout_marginStart="15dp"
android:layout_marginTop="5dp"
android:textSize="16sp"/>
</LinearLayout>
</LinearLayout>MainActivity.kt
添加以下代码以使用DOM解析器读取和解析XML数据。创建DocumentBuilderFactory, DocumentBuilder和Document对象的实例。
HashMap <String, String>用于从XML文档读取数据并将其添加到ArrayList()中。
package example.srcmini02.com.kotlinxmlparsingusingdomparser
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.widget.ListView
import android.widget.SimpleAdapter
import org.w3c.dom.Element
import org.w3c.dom.Node
import org.xml.sax.SAXException
import java.io.IOException
import javax.xml.parsers.DocumentBuilderFactory
import javax.xml.parsers.ParserConfigurationException
class MainActivity : AppCompatActivity() {
var empDataHashMap = HashMap<String, String>()
var empList: ArrayList<HashMap<String, String>> = ArrayList()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
try {
val lv = findViewById<ListView>(R.id.listView)
val istream = assets.open("empdetail.xml")
val builderFactory = DocumentBuilderFactory.newInstance()
val docBuilder = builderFactory.newDocumentBuilder()
val doc = docBuilder.parse(istream)
//reading the tag "employee" of empdetail file
val nList = doc.getElementsByTagName("employee")
for (i in 0 until nList.getLength()) {
if (nList.item(0).getNodeType().equals(Node.ELEMENT_NODE) ) {
//creating instance of HashMap to put the data of node value
empDataHashMap = HashMap()
val element = nList.item(i) as Element
empDataHashMap.put("name", getNodeValue("name", element))
empDataHashMap.put("salary", getNodeValue("salary", element))
empDataHashMap.put("designation", getNodeValue("designation", element))
//adding the HashMap data to ArrayList
empList.add(empDataHashMap)
}
}
val adapter = SimpleAdapter(this@MainActivity, empList, R.layout.custom_list, arrayOf("name", "salary", "designation"), intArrayOf(R.id.name, R.id.salary, R.id.designation))
lv.setAdapter(adapter)
} catch (e: IOException) {
e.printStackTrace()
} catch (e: ParserConfigurationException) {
e.printStackTrace()
} catch (e: SAXException) {
e.printStackTrace()
}
}
// function to return node value
protected fun getNodeValue(tag: String, element: Element): String {
val nodeList = element.getElementsByTagName(tag)
val node = nodeList.item(0)
if (node != null) {
if (node.hasChildNodes()) {
val child = node.getFirstChild()
while (child != null) {
if (child.getNodeType() === Node.TEXT_NODE) {
return child.getNodeValue()
}
}
}
}
return ""
}
}输出：
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