向sd卡备份短信（以xml的格式保存）

 public void click(View v){
     //访问内容提供者获取短信
     ContentResolver cr = getContentResolver();
     //      短信内容提供者的主机名
     Cursor cursor = cr.query(Uri.parse("content://sms"), new String[]{"address", "date", "body", "type"},
       null, null, null);
     while(cursor.moveToNext()){
      String address = cursor.getString(0);
      long date = cursor.getLong(1);
      String body = cursor.getString(2);
      String type = cursor.getString(3);
      Message sms = new Message(body, type, address, date);
      smsList.add(sms);
     }
    }
   
    public void click2(View v){
     XmlSerializer xs = Xml.newSerializer();
     File file = new File("sdcard/sms.xml");
     FileOutputStream fos;
  try {
   fos = new FileOutputStream(file);
   xs.setOutput(fos, "utf-8");
   
   xs.startDocument("utf-8", true);
   xs.startTag(null, "message");
   
   for (Message sms : smsList) {
    xs.startTag(null, "sms");
    
    xs.startTag(null, "body");
    xs.text(sms.getBody());
    xs.endTag(null, "body");
    
    xs.startTag(null, "date");
    xs.text(sms.getDate() + "");
    xs.endTag(null, "date");
    
    xs.startTag(null, "type");
    xs.text(sms.getType());
    xs.endTag(null, "type");
    
    xs.startTag(null, "address");
    xs.text(sms.getAddress());
    xs.endTag(null, "address");
    
    xs.endTag(null, "sms");
   }
   
   xs.endTag(null, "message");
   xs.endDocument();
  } catch (Exception e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
    }