使用AsyncTask从网上获取一个网页，在一个TextView中将其源代码显示出来

使用AsyncTask从网上获取一个网页，在一个TextView中将其源代码显示出来

package test.list;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.util.ArrayList;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class NetworkActivity extends Activity{
    private TextView message;
    private Button open;
    private EditText url;

    @Override
    public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.network);
       message= (TextView) findViewById(R.id.message);
       url= (EditText) findViewById(R.id.url);
       open= (Button) findViewById(R.id.open);
       open.setOnClickListener(new View.OnClickListener() {
           public void onClick(View arg0) {
              connect();
           }
       });

    }

    private void connect() {
        PageTask task = new PageTask(this);
        task.execute(url.getText().toString());
    }


    class PageTask extends AsyncTask {
        // 可变长的输入参数，与AsyncTask.exucute()对应
        ProgressDialog pdialog;
        public PageTask(Context context){
            pdialog = new ProgressDialog(context, 0);   
            pdialog.setButton("cancel", new DialogInterface.OnClickListener() {
             public void onClick(DialogInterface dialog, int i) {
              dialog.cancel();
             }
            });
            pdialog.setOnCancelListener(new DialogInterface.OnCancelListener() {
             public void onCancel(DialogInterface dialog) {
              finish();
             }
            });
            pdialog.setCancelable(true);
            pdialog.setMax(100);
            pdialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
            pdialog.show();


        }
        @Override
        protected String doInBackground(String... params) {

            try{

               HttpClient client = new DefaultHttpClient();
               // params[0]代表连接的url
               HttpGet get = new HttpGet(params[0]);
               HttpResponse response = client.execute(get);
               HttpEntity entity = response.getEntity();
               long length = entity.getContentLength();
               InputStream is = entity.getContent();
               String s = null;
               if(is != null) {
                   ByteArrayOutputStream baos = new ByteArrayOutputStream();

                   byte[] buf = new byte[128];

                   int ch = -1;

                   int count = 0;

                   while((ch = is.read(buf)) != -1) {

                      baos.write(buf, 0, ch);

                      count += ch;

                      if(length > 0) {
                          // 如果知道响应的长度，调用publishProgress（）更新进度
                          publishProgress((int) ((count / (float) length) * 100));
                      }

                      // 让线程休眠100ms
                      Thread.sleep(100);
                   }
                   s = new String(baos.toByteArray());              }
               // 返回结果
               return s;
            } catch(Exception e) {
               e.printStackTrace();

            }

            return null;

        }

        @Override
        protected void onCancelled() {
            super.onCancelled();
        }

        @Override
        protected void onPostExecute(String result) {
            // 返回HTML页面的内容
            message.setText(result);
            pdialog.dismiss(); 
        }

        @Override
        protected void onPreExecute() {
            // 任务启动，可以在这里显示一个对话框，这里简单处理
            message.setText(R.string.task_started);
        }

        @Override
        protected void onProgressUpdate(Integer... values) {
            // 更新进度
              System.out.println(""+values[0]);
              message.setText(""+values[0]);
              pdialog.setProgress(values[0]);
        }

     }

}