Android（java）学习笔记203：网页源码查看器

1.项目框架图：

2.首先是布局文件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" >

    <EditText
        android:id="@+id/et_path"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="http://192.168.1.100:8080/hello.jsp" />

    <Button
        android:onClick="click"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="查看源码" />

    <ScrollView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >

        <TextView
            android:id="@+id/tv_result"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent" />
    </ScrollView>

</LinearLayout>

3.MainActivity.java:

 1 package com.itheima.netsourceviewer;
 2
 3 import java.io.InputStream;
 4 import java.net.HttpURLConnection;
 5 import java.net.URL;
 6
 7 import android.app.Activity;
 8 import android.os.Bundle;
 9 import android.os.Handler;
10 import android.os.Message;
11 import android.view.View;
12 import android.widget.EditText;
13 import android.widget.TextView;
14 import android.widget.Toast;
15
16 import com.itheima.netsourceviewer.utils.StreamTools;
17
18 public class MainActivity extends Activity {
19     protected static final int SUCCESS = 1;
20     protected static final int ERROR = 2;
21
22     private EditText et_path;
23     private TextView tv_result;
24
25     private Handler handler = new Handler(){
26         public void handleMessage(android.os.Message msg) {
27             switch (msg.what) {
28             case SUCCESS:
29                 String text = (String) msg.obj;
30                 tv_result.setText(text);
31                 break;
32             case ERROR:
33                 Toast.makeText(MainActivity.this, "请求失败", 1).show();
34                 break;
35             }
36         };
37     };
38
39     @Override
40     protected void onCreate(Bundle savedInstanceState) {
41         super.onCreate(savedInstanceState);
42         setContentView(R.layout.activity_main);
43         et_path = (EditText) findViewById(R.id.et_path);
44         tv_result = (TextView) findViewById(R.id.tv_result);
45     }
46     /**
47      * 查看源文件的点击事件
48      * @param view
49      */
50     public void click(View view){
51         final String path = et_path.getText().toString().trim();
52         //访问网络，把html源文件下载下来
53         new Thread(){
54             public void run() {
55                 try {
56                     //获取url对象
57                     URL url = new URL(path);
58                     //获取链接对象
59                     HttpURLConnection conn = (HttpURLConnection) url.openConnection();
60                     //获取请求方式，默认GET
61                     conn.setRequestMethod("GET");//声明请求方式 默认get
62                     //告诉服务器我是什么样的客户端
63                     conn.setRequestProperty("User-Agent", "Mozilla/5.0 (Linux; U; Android 2.3.3; zh-cn; sdk Build/GRI34) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1 MicroMessenger/6.0.0.57_r870003.501 NetType/internet");
64                     //获取状态吗
65                     int code = conn.getResponseCode();
66                     //判断状态吗
67                     if(code ==200){
68                         InputStream is = conn.getInputStream();
69                         //使用工具类， 吧字节输入流的数据编程字符串
70                         String result = StreamTools.readStream(is);
71
72                         Message msg = Message.obtain();//减少消息创建的数量
73                         msg.obj = result;
74                         msg.what = SUCCESS;
75                         handler.sendMessage(msg);
76                     }
77                 } catch (Exception e) {
78                     Message msg = Message.obtain();//减少消息创建的数量
79                     msg.what = ERROR;
80                     handler.sendMessage(msg);
81                     e.printStackTrace();
82                 }
83             };
84         }.start();
85     }
86 }

4.这里的工具类是StreamTools.java:

 1 package com.itheima.netsourceviewer.utils;
 2
 3 import java.io.ByteArrayOutputStream;
 4 import java.io.IOException;
 5 import java.io.InputStream;
 6
 7 /**
 8  * 流的工具类
 9  * @author Administrator
10  *
11  */
12 public class StreamTools {
13     /**
14      * 把输入流的内容转换成字符串
15      * @param is
16      * @return null解析失败， string读取成功
17      */
18     public static String readStream(InputStream is) {
19         try {
20             ByteArrayOutputStream baos = new ByteArrayOutputStream();
21             byte[] buffer = new byte[1024];
22             int len = -1;
23             while( (len = is.read(buffer))!=-1){
24                 baos.write(buffer, 0, len);
25             }
26             is.close();
27             String temptext = new String(baos.toByteArray());
28             if(temptext.contains("charset=gb2312")){//解析meta标签
29                 return new String(baos.toByteArray(),"gb2312");
30             }else{
31                 return new String(baos.toByteArray(),"utf-8");
32             }
33         } catch (IOException e) {
34             e.printStackTrace();
35             return null;
36         }
37     }
38 }