从网上获取一个网页，在一个TextView中将其源代码显示出来

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<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();

        }

        @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]);
        }
    }
}