编写如下项目：
2 编写Android清单文件
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.itheima28.htmldemo"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="19" />
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.itheima28.htmldemo.MainActivity"
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>
</manifest>
3 编写布局文件activity_main.xml
<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" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<EditText
android:id="@+id/et_url"
android:layout_width="0dip"
android:text="http://www.baidu.com"
android:layout_height="wrap_content"
android:singleLine="true"
android:layout_weight="1"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="getHtml"
android:text="GO"/>
</LinearLayout>
<ScrollView
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:id="@+id/tv_html"
android:layout_width="fill_parent"
android:layout_height="fill_parent"/>
</ScrollView>
</LinearLayout>
4 编写Activity的类MainActivity如下：
package com.itheima28.htmldemo;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
private static final String TAG = "MainActivity";
private static final int SUCCESS = 0;
protected static final int ERROR = 1;
private EditText etUrl;
private TextView tvHtml;
private Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
switch (msg.what) {
case SUCCESS:
tvHtml.setText((String) msg.obj);
break;
case ERROR:
Toast.makeText(MainActivity.this, "访问失败", 0).show();
break;
default:
break;
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
etUrl = (EditText) findViewById(R.id.et_url);
tvHtml = (TextView) findViewById(R.id.tv_html);
}
public void getHtml(View v) {
final String url = etUrl.getText().toString();
new Thread(new Runnable() {
@Override
public void run() {
// 请求网络
String html = getHtmlFromInternet(url);
if(!TextUtils.isEmpty(html)) {
// 更新textview的显示了
Message msg = new Message();
msg.what = SUCCESS;
msg.obj = html;
handler.sendMessage(msg);
} else {
Message msg = new Message();
msg.what = ERROR;
handler.sendMessage(msg);
}
}
}).start();
}
/**
* 根据给定的url访问网络, 抓去html代码
* @param url
* @return
*/
protected String getHtmlFromInternet(String url) {
try {
URL mURL = new URL(url);
HttpURLConnection conn = (HttpURLConnection) mURL.openConnection();
conn.setRequestMethod("GET");
conn.setConnectTimeout(10000);
conn.setReadTimeout(5000);
// conn.connect();
int responseCode = conn.getResponseCode();
if(responseCode == 200) {
InputStream is = conn.getInputStream();
String html = getStringFromInputStream(is);
return html;
} else {
Log.i(TAG, "访问失败: " + responseCode);
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 根据流返回一个字符串信息
* @param is
* @return
* @throws IOException
*/
private String getStringFromInputStream(InputStream is) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len = -1;
while((len = is.read(buffer)) != -1) {
baos.write(buffer, 0, len);
}
is.close();
String html = baos.toString(); // 把流中的数据转换成字符串, 采用的编码是: utf-8
String charset = "utf-8";
if(html.contains("gbk") || html.contains("gb2312")
|| html.contains("GBK") || html.contains("GB2312")) { // 如果包含gbk, gb2312编码, 就采用gbk编码进行对字符串编码
charset = "gbk";
}
html = new String(baos.toByteArray(), charset); // 对原有的字节数组进行使用处理后的编码名称进行编码
baos.close();
return html;
}
}