android 74 下载文本

<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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity"
android:orientation="vertical"
>

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="查看源文件"
android:onClick="click"
/>
<ScrollView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
>
<TextView
android:id="@+id/tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
</ScrollView>
</LinearLayout>

package com.itheima.htmlviewer;

import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import com.itheima.htmlviewer.utils.Utils;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.TextView;
//请求网上的文本（网页）
public class MainActivity extends Activity {

Handler handler = new Handler(){
public void handleMessage(android.os.Message msg) {
TextView tv = (TextView) findViewById(R.id.tv);
tv.setText((String)msg.obj);
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}

public void click(View v){
Thread t = new Thread(){
@Override
public void run() {
String path = "http://192.168.13.13:8080/baidu.html";
try {
URL url = new URL(path);
//获取连接对象，此时还未建立连接
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
conn.setConnectTimeout(5000);
conn.setReadTimeout(5000);
//先建立连接，然后获取响应码
if(conn.getResponseCode() == 200){
//拿到服务器返回的输入流，流里的数据就是html的源文件
InputStream is = conn.getInputStream();
//从流里把文本数据取出来
String text = Utils.getTextFromStream(is);

//发送消息，让主线程刷新ui，显示源文件
Message msg = handler.obtainMessage();
msg.obj = text;
handler.sendMessage(msg);
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
};
t.start();

}

}

package com.itheima.htmlviewer.utils;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

public class Utils {

public static String getTextFromStream(InputStream is){
//乱码是因为服务器和客户端码表不一致
byte[] b = new byte[1024];
int len = 0;
//创建字节数组输出流，读取输入流的文本数据时，同步把数据写入数组输出流
ByteArrayOutputStream bos = new ByteArrayOutputStream();
try {
while((len = is.read(b)) != -1){
bos.write(b, 0, len);//写入到数组输出流
}
//把字节数组输出流里的数据转换成字节数组
String text = new String(bos.toByteArray(),"utf-8");//安卓默认是utf-8
return text;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
}