Android中创建与几种解析xml的方法!-白红宇

Android中创建与几种解析xml的方法!

阅读量：7184 次

发布时间：2019-06-29

本文共 7326 字，大约阅读时间需要 24 分钟。

首先是创建，我们用XmlSerializer这个类来创建一个xml文件，其次是解析xml文件，常用的有dom,sax,XmlPullParser等方法，由于sax代码有点复杂，本节只讲解一下dom与XmlPullParser解析，至于几种解析xml的优缺点我就不再讲述了。

为了方便理解，我做了一个简单的Demo。首先首界面有三个按钮，点击第一个按钮会在sdcard目录下创建一个books.xml文件,另外两个按钮分别是调用dom与XmlPullParser方法解析xml文件，并将结果显示在一个TextView里。大家可以按照我的步骤一步步来:

第一步:新建一个Android工程,命名为XmlDemo.

第二步:修改main.xml布局文件，代码如下:

xml

version

="1.0"

encoding

="utf-8"

LinearLayout

xmlns:android

="http://schemas.android.com/apk/res/android"

android:orientation

="vertical"

android:layout_width

="fill_parent"

android:layout_height

="fill_parent"

Button

android:id

="@+id/btn1"

android:layout_width

="fill_parent"

android:layout_height

="wrap_content"

android:text

="创建XML文件"

Button

android:id

="@+id/btn2"

android:layout_width

="fill_parent"

android:layout_height

="wrap_content"

android:text

="DOM解析XML"

Button

android:id

="@+id/btn3"

android:layout_width

="fill_parent"

android:layout_height

="wrap_content"

android:text

="XmlPullParse解析XML"

TextView

android:id

="@+id/result"

android:layout_width

="fill_parent"

android:layout_height

="wrap_content"

LinearLayout

第三步:修改主核心程序XmlDemo.java,代码如下:

package com.tutor.xml;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;

import org.w3c.dom.Element;

import org.w3c.dom.NodeList;

import org.xml.sax.SAXException;

import org.xmlpull.v1.XmlPullParser;

import org.xmlpull.v1.XmlPullParserException;

import org.xmlpull.v1.XmlPullParserFactory;

import org.xmlpull.v1.XmlSerializer;

import android.app.Activity;

import android.os.Bundle;

import android.util.Log;

import android.util.Xml;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.TextView;

import android.widget.Toast;

public

class XmlDemo

extends Activity

implements OnClickListener {

private

static

final String BOOKS_PATH =

"/sdcard/books.xml";

private Button mButton1,mButton2,mButton3;

private TextView mTextView;

@Override

public

void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

setupViews();

}

//初始化工作

private

void setupViews(){

mTextView = (TextView)findViewById(R.id.result);

mButton1 = (Button)findViewById(R.id.btn1);

mButton2 = (Button)findViewById(R.id.btn2);

mButton3 = (Button)findViewById(R.id.btn3);

mButton1.setOnClickListener(

this);

mButton2.setOnClickListener(

this);

mButton3.setOnClickListener(

this);

}

//创建xml文件

private

void createXmlFile(){

File linceseFile =

new File(BOOKS_PATH);

try{

linceseFile.createNewFile();

}

catch (IOException e) {

Log.e(

"IOException",

"exception in createNewFile() method");

}

FileOutputStream fileos =

null;

try{

fileos =

new FileOutputStream(linceseFile);

}

catch (FileNotFoundException e) {

Log.e(

"FileNotFoundException",

"can't create FileOutputStream");

}

XmlSerializer serializer = Xml.newSerializer();

try {

serializer.setOutput(fileos,

"UTF-8");

serializer.startDocument(

null,

true);

serializer.startTag(

null,

"books");

for(

int i = 0; i < 3; i ++){

serializer.startTag(

null,

"book");

serializer.startTag(

null,

"bookname");

serializer.text(

"Android教程" + i);

serializer.endTag(

null,

"bookname");

serializer.startTag(

null,

"bookauthor");

serializer.text(

"Frankie" + i);

serializer.endTag(

null,

"bookauthor");

serializer.endTag(

null,

"book");

}

serializer.endTag(

null,

"books");

serializer.endDocument();

serializer.flush();

fileos.close();

}

catch (Exception e) {

Log.e(

"Exception",

"error occurred while creating xml file");

}

Toast.makeText(getApplicationContext(),

"创建xml文件成功!", Toast.LENGTH_SHORT).show();

}

//dom解析xml文件

private

void domParseXML(){

File file =

new File(BOOKS_PATH);

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

DocumentBuilder db =

null;

try {

db = dbf.newDocumentBuilder();

}

catch (ParserConfigurationException e) {

e.printStackTrace();

}

Document doc =

null;

try {

doc = db.parse(file);

}

catch (SAXException e) {

e.printStackTrace();

}

catch (IOException e) {

e.printStackTrace();

}

Element root = doc.getDocumentElement();

NodeList books = root.getElementsByTagName(

"book");

String res =

"本结果是通过dom解析:" +

"/n";

for(

int i = 0; i < books.getLength();i++){

Element book = (Element)books.item(i);

Element bookname = (Element)book.getElementsByTagName(

"bookname").item(0);

Element bookauthor = (Element)book.getElementsByTagName(

"bookauthor").item(0);

res +=

"书名: " + bookname.getFirstChild().getNodeValue() +

" " +

"作者: " + bookauthor.getFirstChild().getNodeValue() +

"/n";

}

mTextView.setText(res);

}

//xmlPullParser解析xml文件

private

void xmlPullParseXML(){

String res =

"本结果是通过XmlPullParse解析:" +

"/n";

try {

XmlPullParserFactory factory = XmlPullParserFactory.newInstance();

XmlPullParser xmlPullParser = factory.newPullParser();

xmlPullParser.setInput(Thread.currentThread().getContextClassLoader()

.getResourceAsStream(BOOKS_PATH),

"UTF-8");

int eventType = xmlPullParser.getEventType();

try{

while (eventType != XmlPullParser.END_DOCUMENT) {

String nodeName = xmlPullParser.getName();

switch (eventType) {

case XmlPullParser.START_TAG:

if(

"bookname".equals(nodeName)){

res +=

"书名: " + xmlPullParser.nextText() +

" ";

}

else

if(

"bookauthor".equals(nodeName)){

res +=

"作者: " + xmlPullParser.nextText() +

"/n";

}

break;

default:

break;

}

eventType = xmlPullParser.next();

}

catch (IOException e) {

e.printStackTrace();

}

catch (XmlPullParserException e) {

e.printStackTrace();

}

mTextView.setText(res);

}

//按钮事件响应

public

void onClick(View v) {

if(v == mButton1){

createXmlFile();

}

else

if(v == mButton2){

domParseXML();

}

else

if(v == mButton3){

xmlPullParseXML();

}

第四步:由于我们在Sd卡上新建了文件，需要增加权限，如下代码(第16行):

xml

version

="1.0"

encoding

="utf-8"

manifest

xmlns:android

="http://schemas.android.com/apk/res/android"

package

="com.tutor.xml"

android:versionCode

="1"

android:versionName

="1.0"

application

android:icon

="@drawable/icon"

android:label

="@string/app_name"

activity

android:name

=".XmlDemo"

android:label

="@string/app_name"

intent-filter

action

android:name

="android.intent.action.MAIN"

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转载于:https://blog.51cto.com/whatandroid/817426

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