widget ----AlertDialog

  new AlertDialog.Builder(EX03_12.this) ---EX03_12.this是当前Context
        .setTitle(R.string.app_about)  ---这里是标题
        .setMessage(R.string.app_about_msg) ---这里是内容
        .setPositiveButton(R.string.str_ok, ---设置确定按钮
           new DialogInterface.OnClickListener()  ---确定按钮的事件
            {
           public void onClick(DialogInterface dialoginterface, int i)
             {
             }
             }
            )
        .show();