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

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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;@Overridepublic 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<String, Integer, String> {// 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();}@Overrideprotected String doInBackground(String... params) {try{HttpClient client = new DefaultHttpClient();// params[0]代表连接的urlHttpGet 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100msThread.sleep(100);}s = new String(baos.toByteArray());              }// 返回结果return s;} catch(Exception e) {e.printStackTrace();}return null;}@Overrideprotected void onCancelled() {super.onCancelled();}@Overrideprotected void onPostExecute(String result) {// 返回HTML页面的内容message.setText(result);pdialog.dismiss(); }@Overrideprotected 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);}@Overrideprotected void onProgressUpdate(Integer... values) {// 更新进度System.out.println(""+values[0]);message.setText(""+values[0]);pdialog.setProgress(values[0]);}}}

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