android学习笔记之访问互联网
本帖最后由 青玄 于 2014-11-6 21:29 编辑访问互联网读取网页代码：
所需要的权限：
<uses-permission android:name="android.permission.INTERNET"/>
读取内容的类：package com.example.loadhtml_test.util;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
public class Utils {
public static String getInternetData(InputStream is)
{
try
{
ByteArrayOutputStream baos = new ByteArrayOutputStream(); //字节数据输出流
byte[] buffer = new byte; //字节数组
int len = -1;
while((len = is.read(buffer)) != -1) //将输入流里面的内容读到字节数组里面
{
baos.write(buffer, 0, len);//再将字节数组里面的内容写到字节数组输出流里面
}
String content = new String(baos.toByteArray(), "GBK");//将这个内容转化为字符串并设置它的编码
if(content.contains("content=\"text/html;charset=utf-8\""))//如果编码为utf-8的话
{
return new String(baos.toByteArray(),"utf-8"); //就设置utf-8编码
}
return content;
}catch(Exception e)
{
e.printStackTrace();
return null;
}
}
}
本程序的主类：package com.example.loadhtml_test;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import com.example.loadhtml_test.util.Utils;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.text.TextUtils;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
private TextView tv;
private EditText et;
private Handler handler;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.tv = (TextView) this.findViewById(R.id.ty);
this.et = (EditText) this.findViewById(R.id.et);
handler = new Handler(){
@Override
public void handleMessage(Message msg) { //主线程中接收子线程发来的消息方法
// TODO Auto-generated method stub
if(msg.what == 1)
{
tv.setText((String)msg.obj);
}else if(msg.what == 2)
{
Toast.makeText(MainActivity.this, "网络链接有误", Toast.LENGTH_LONG).show();
}
}
};
}
public void showData(View v) //点击事件的方法
{
final String path = et.getText().toString().trim();//获取网址路径
if(!TextUtils.isEmpty(path))
{
new Thread() //开一个子线程
{
public void run()
{
try
{
URL url = new URL(path); //得到网址路径，并把它装在URL里面
//通过url获得HttpURLConnection对象
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET"); //设置请求的方法
conn.setConnectTimeout(5000); //设置链接的时长
conn.setRequestProperty("Accept","image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/msword, application/vnd.ms-excel, application/vnd.ms-powerpoint, */*");
conn.setRequestProperty("User-Agent","Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0)");
int code = conn.getResponseCode(); //获得服务器发过来的返回码
if(code == 200) //如果是200的话
{
final InputStream is = conn.getInputStream(); //从这个链接对象里面获取输入流
final String content = Utils.getInternetData(is);//调用这个方法获取网页的代码
if(content != null)
{
Message msg = Message.obtain(); //得到消息对象
msg.what = 1; //设置消息
msg.obj = content;//给消息一个对象传过去
handler.sendMessage(msg); //发送消息
}else
{
Message msg = Message.obtain();
msg.what = 2;
handler.sendMessage(msg);
}
}
}catch(Exception e)
{
e.printStackTrace();
}
}
}.start();
}else
{
Toast.makeText(this, "获取内容失败", Toast.LENGTH_LONG).show();
}
}
}
3.xml布局文件：
<LinearLayout 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"
android:orientation="vertical"
tools:context=".MainActivity" >
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="20"
>
<TextView
android:id="@+id/ty"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</ScrollView>
<EditText
android:id="@+id/et"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="showData"
android:text="获得网页内容"
/>
</LinearLayout>
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