ANDROID_MARS学习笔记_S01原始版_011_XML

一、代码

1.xml
(1)main.xml

<?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/parseButton"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="开始解析XML"
/>
</LinearLayout>

(2)AndroidManifest.xml.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.s01_original_e20_xml"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="21" />

<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".XMLActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<uses-permission android:name="android.permission.INTERNET"/>
</manifest>

2.java
(1)XMLActivity.java

package com.example.s01_original_e20_xml;

import java.io.StringReader;

import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

import com.example.s01_original_e20_xml.util.HttpDownloader;

public class XMLActivity extends Activity {
/** Called when the activity is first created. */
private Button parseButton ;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
parseButton = (Button)findViewById(R.id.parseButton);
parseButton.setOnClickListener(new ParseButtonListener());
}

class ParseButtonListener implements OnClickListener{

@Override
public void onClick(View v) {
HttpDownloader hd = new HttpDownloader();
String resultStr = hd.download("http://192.168.1.104:8080/goods/test.xml");
System.out.println(resultStr);
try{
//创建一个SAXParserFactory
SAXParserFactory factory = SAXParserFactory.newInstance();
XMLReader reader = factory.newSAXParser().getXMLReader();
//为XMLReader设置内容处理器
reader.setContentHandler(new MyContentHandler());
//开始解析文件
reader.parse(new InputSource(new StringReader(resultStr)));
}
catch(Exception e){
e.printStackTrace();
}
}

}
}

(2)MyContentHandler.java

package com.example.s01_original_e20_xml;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

public class MyContentHandler extends DefaultHandler {
String hisname, address, money, sex, status;
String tagName;

public void startDocument() throws SAXException {
System.out.println("````````begin````````");
}

public void endDocument() throws SAXException {
System.out.println("````````end````````");
}

//localName不带前缀，qName带前缀
public void startElement(String namespaceURI, String localName,
String qName, Attributes attr) throws SAXException {
tagName = localName;
if (localName.equals("worker")) {
//获取标签的全部属性
for (int i = 0; i < attr.getLength(); i++) {
System.out.println(attr.getLocalName(i) + "=" + attr.getValue(i));
}
}
}

public void endElement(String namespaceURI, String localName, String qName)
throws SAXException {
//在workr标签解析完之后，会打印出所有得到的数据
tagName = "";
if (localName.equals("worker")) {
this.printout();
}
}
public void characters(char[] ch, int start, int length)
throws SAXException {
if (tagName.equals("name"))
hisname = new String(ch, start, length);
else if (tagName.equals("sex"))
sex = new String(ch, start, length);
else if (tagName.equals("status"))
status = new String(ch, start, length);
else if (tagName.equals("address"))
address = new String(ch, start, length);
else if (tagName.equals("money"))
money = new String(ch, start, length);
}

private void printout() {
System.out.print("name: ");
System.out.println(hisname);
System.out.print("sex: ");
System.out.println(sex);
System.out.print("status: ");
System.out.println(status);
System.out.print("address: ");
System.out.println(address);
System.out.print("money: ");
System.out.println(money);
System.out.println();
}

}

(3)HttpDownloader.java

package com.example.s01_original_e20_xml.util;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

public class HttpDownloader {
private URL url = null;

/**
* 根据URL下载文件，前提是这个文件当中的内容是文本，函数的返回值就是文件当中的内容
* 1.创建一个URL对象
* 2.通过URL对象，创建一个HttpURLConnection对象
* 3.得到InputStram
* 4.从InputStream当中读取数据
* @param urlStr
* @return
*/
public String download(String urlStr) {
StringBuffer sb = new StringBuffer();
String line = null;
BufferedReader buffer = null;
try {
// 创建一个URL对象
url = new URL(urlStr);
// 创建一个Http连接
HttpURLConnection urlConn = (HttpURLConnection) url
.openConnection();
// 使用IO流读取数据
buffer = new BufferedReader(new InputStreamReader(urlConn
.getInputStream()));
while ((line = buffer.readLine()) != null) {
sb.append(line);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
buffer.close();
} catch (Exception e) {
e.printStackTrace();
}
}
return sb.toString();
}

/**
* 该函数返回整形 -1：代表下载文件出错 0：代表下载文件成功 1：代表文件已经存在
*/
public int downFile(String urlStr, String path, String fileName) {
InputStream inputStream = null;
try {
FileUtils fileUtils = new FileUtils();

if (fileUtils.isFileExist(path + fileName)) {
return 1;
} else {
inputStream = getInputStreamFromUrl(urlStr);
File resultFile = fileUtils.write2SDFromInput(path,fileName, inputStream);
if (resultFile == null) {
return -1;
}
}
} catch (Exception e) {
e.printStackTrace();
return -1;
} finally {
try {
inputStream.close();
} catch (Exception e) {
e.printStackTrace();
}
}
return 0;
}

/**
* 根据URL得到输入流
*
* @param urlStr
* @return
* @throws MalformedURLException
* @throws IOException
*/
public InputStream getInputStreamFromUrl(String urlStr)
throws MalformedURLException, IOException {
url = new URL(urlStr);
HttpURLConnection urlConn = (HttpURLConnection) url.openConnection();
InputStream inputStream = urlConn.getInputStream();
return inputStream;
}
}

(4)FileUtils.java

package com.example.s01_original_e20_xml.util;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.os.Environment;

public class FileUtils {
private String SDPATH;

public String getSDPATH() {
return SDPATH;
}
public FileUtils() {
//得到当前外部存储设备的目录
// /SDCARD
SDPATH = Environment.getExternalStorageDirectory() + "/";
}
/**
* 在SD卡上创建文件
*
* @throws IOException
*/
public File creatSDFile(String fileName) throws IOException {
File file = new File(SDPATH + fileName);
file.createNewFile();
return file;
}

/**
* 在SD卡上创建目录
*
* @param dirName
*/
public File creatSDDir(String dirName) {
File dir = new File(SDPATH + dirName);
dir.mkdir();
return dir;
}

/**
* 判断SD卡上的文件夹是否存在
*/
public boolean isFileExist(String fileName){
File file = new File(SDPATH + fileName);
return file.exists();
}

/**
* 将一个InputStream里面的数据写入到SD卡中
*/
public File write2SDFromInput(String path,String fileName,InputStream input){
File file = null;
OutputStream output = null;
try{
creatSDDir(path);
file = creatSDFile(path + fileName);
output = new FileOutputStream(file);
byte buffer [] = new byte[4 * 1024];
while((input.read(buffer)) != -1){
output.write(buffer);
}
output.flush();
}
catch(Exception e){
e.printStackTrace();
}
finally{
try{
output.close();
}
catch(Exception e){
e.printStackTrace();
}
}
return file;
}

}

PS：在HttpDownLoader.java的buffer = new BufferedReader(new InputStreamReader(urlConn .getInputStream()));，返回的buffer为空，不知原因

A:那是因为新的sdk不允许在main线程里访问网络，否则会抛android.os.NetworkOnMainThreadException，解决方法：http://www.2cto.com/kf/201402/281526.html

在MainActivity文件的setContentView(R.layout.activity_main)下面加上如下代码

if (android.os.Build.VERSION.SDK_INT > 9) {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
}