1.android的API提供了訪問網絡的一個類HttpURLConnection

2.通過發送GET請求獲取服務器返回的html代碼

3.先看看布局文件，如下所示，

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <EditText        android:id="@+id/et"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <Button        android:onClick="get"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="獲取源碼"/>
    <ScrollView        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <TextView            android:id="@+id/tv"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
           android:textColor="#00f"
            android:hint="源碼顯示"/>
    </ScrollView></LinearLayout>

布局樣子：

4.下來是清單文件，記得連接網絡要添加權限

5.1再看java代碼，MainActivity的

package com.market.source;import android.app.Activity;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.EditText;import android.widget.TextView;import java.io.IOException;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.ProtocolException;import java.net.URL;import java.net.URLConnection;import butterknife.BindView;import butterknife.ButterKnife;public class MainActivity extends Activity {

    @BindView(R.id.et)
     EditText et;

    @BindView(R.id.tv)
     TextView tv;


    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);
    }    public void get(View vew) throws IOException {        final String str = et.getText().toString().trim();        new Thread(){

            @Override            public void run() {                //1.請求地址url
                URL url = null;                try {
                    url = new URL(str);                    //2.獲取對這個地址的連接
                    HttpURLConnection con = (HttpURLConnection) url.openConnection();                    //3.設置對這個地址的請求,GET請求
                    con.setRequestMethod("GET");                    //4.設置請求參數
                    con.setConnectTimeout(5000);                    //5.獲取服務器的響應
                    int code = con.getResponseCode();                    //6.根據響應嗎，判斷請求成功還是失敗，200成功
                    if(code==200){                        //7.成功的話，服務器一流的形式返回數據
                        InputStream inputStream = con.getInputStream();                        //8.這個流是字節流，需要我們轉換為字符流才可以認識
                        final String info = StreamTool.StreamtoString(inputStream);
                        Log.e("MainActivity",info);
                        runOnUiThread(new Runnable() {
                            @Override                            public void run() {
                                tv.setText(info);
                            }
                        });

                    }
                } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (ProtocolException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }


            }




        }.start();
    }


}

5.2工具類，用來將一個流轉化為字符串

public class StreamTool {    public static String StreamtoString(InputStream inputStream) {        int len = -1;        byte[] buffer = new byte[1024];        //內存數組輸出流
        ByteArrayOutputStream baos = new ByteArrayOutputStream();        try {            while((len=inputStream.read(buffer)) != -1){

               baos.write(buffer,0,len);
            }
            String str = new String(baos.toByteArray());            return str;

        } catch (IOException e) {
            e.printStackTrace();
        }finally {            try {
                inputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }        return null;
    }

}

6.運行效果查看

html查看器android