Android XMLPullParser教程

Android建議使用XMLPullParser來解析xml文件，而不是SAX和DOM，因為它速度快。愛掏網 - it200.com

org.xmlpull.v1.XmlPullParser 接口提供了使用XMLPullParser解析XML文檔的功能。愛掏網 - it200.com

XmlPullParser的事件

XMLPullParser的 next()方法 將光標指針移到下一個事件。愛掏網 - it200.com通常，我們使用XMLPullParser接口中定義的四個常量（作為事件）。愛掏網 - it200.com

START_TAG :讀取了一個XML開始標簽。愛掏網 - it200.com

TEXT :讀取了文本內容；可以使用getText()方法獲取文本內容。愛掏網 - it200.com

END_TAG :讀取了一個結束標簽。愛掏網 - it200.com

END_DOCUMENT :沒有更多的事件可用

Android XMLPullParser示例

activity_main.xml

從palette中拖動一個listview。愛掏網 - it200.com現在activity_main.xml文件的內容如下：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <ListView
        android:id="@+id/listView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

    </ListView>

</RelativeLayout>

XML文檔

在項目的assets目錄下創建一個名為employees.xml的xml文件。愛掏網 - it200.com

<?xml version="1.0" encoding="UTF-8"?>
<employees>
    <employee>
        <id>1</id>
        <name>Sachin</name>
        <salary>50000</salary>      
    </employee>
    <employee>
        <id>2</id>
        <name>Nikhil</name>
        <salary>60000</salary>  
    </employee>

</employees>

Employee類

現在創建與xml文件相對應的雇員類。愛掏網 - it200.com

package com.example.xmlpullparsing;
public class Employee {
     private int id;
     private String name;
     private float salary;
        public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public float getSalary() {
        return salary;
    }
    public void setSalary(float salary) {
        this.salary = salary;
    }

    @Override
    public String toString() {
        return " Id= "+id + "\n Name= " + name + "\n Salary= " + salary;
    }
}

XMLPullParserHandler類

現在編寫使用XMLPullParser解析xml文件的代碼。愛掏網 - it200.com在這里，我們將以列表形式返回所有的員工。愛掏網 - it200.com

package com.example.xmlpullparsing;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlPullParserFactory;


public class XmlPullParserHandler {
    private List<Employee> employees= new ArrayList<Employee>();
    private Employee employee;
    private String text;

    public List<Employee> getEmployees() {
        return employees;
    }

    public List<Employee> parse(InputStream is) {
           try {
            XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
            factory.setNamespaceAware(true);
            XmlPullParser  parser = factory.newPullParser();

            parser.setInput(is, null);

            int eventType = parser.getEventType();
            while (eventType != XmlPullParser.END_DOCUMENT) {
                String tagname = parser.getName();
                switch (eventType) {
                case XmlPullParser.START_TAG:
                    if (tagname.equalsIgnoreCase("employee")) {
                        // create a new instance of employee
                        employee = new Employee();
                    }
                    break;

                case XmlPullParser.TEXT:
                    text = parser.getText();
                    break;

                case XmlPullParser.END_TAG:
                    if (tagname.equalsIgnoreCase("employee")) {
                        // add employee object to list
                        employees.add(employee);
                    }else if (tagname.equalsIgnoreCase("id")) {
                        employee.setId(Integer.parseInt(text));
                    }  else if (tagname.equalsIgnoreCase("name")) {
                        employee.setName(text);
                    } else if (tagname.equalsIgnoreCase("salary")) {
                        employee.setSalary(Float.parseFloat(text));
                    } 
                    break;

                default:
                    break;
                }
                eventType = parser.next();
            }

        } catch (XmlPullParserException e) {e.printStackTrace();} 
        catch (IOException e) {e.printStackTrace();}

        return employees;
    }
}

MainActivity類

現在，編寫代碼將列表數據顯示在ListView中。愛掏網 - it200.com

package com.example.xmlpullparsing;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

       ListView listView = (ListView) findViewById(R.id.listView1);

        List<Employee> employees = null;
        try {
            XmlPullParserHandler parser = new XmlPullParserHandler();
            InputStream is=getAssets().open("employees.xml");
            employees = parser.parse(is);

            ArrayAdapter<Employee> adapter =new ArrayAdapter<Employee>
    (this,android.R.layout.simple_list_item_1, employees);
            listView.setAdapter(adapter);

        } catch (IOException e) {e.printStackTrace();}

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

}

下載這個示例

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