android中怎么动态更新dialog中的textview

如图 我想更新dialog中这个下载网速和百分比 需要不断更新

代码如下：
View convertView = LayoutInflater.from(
context).inflate(
R.layout.download_dialog, null);
((TextView) convertView
.findViewById(R.id.title_tv))
.setText(R.string.text_downloading);
speed = ((TextView) convertView
.findViewById(R.id.tv_speed));
percent = ((TextView) convertView.findViewById(R.id.tv_pencent));
progressBar = ((ProgressBar) convertView.findViewById(R.id.progressBar));
progressBar.setMax(100);
Builder builder = new AlertDialog.Builder(
context);
m_progressDlg = builder.create();
m_progressDlg.show();
m_progressDlg.setContentView(convertView);
m_progressDlg.setCancelable(false);
m_progressDlg.setCanceledOnTouchOutside(false);