android中将内存中的数据以xml的文件格式写到sdcard中

List<SMSInfo> smsInfos = service.getSMSInof();
try {
	File file = new File("/sdcard/smsbackup.xml");
	
	XmlSerializer serializer = Xml.newSerializer();
	FileOutputStream fos = new FileOutputStream(file);
	serializer.setOutput(fos, "UTF-8");
	serializer.startDocument("UTF-8", true);
	serializer.startTag(null, "smss");
	
	serializer.startTag(null, "count");
	serializer.text(smsInfos.size()+"");
	serializer.endTag(null, "count");
	
	for (SMSInfo smsInfo : smsInfos) {
		serializer.startTag(null, "sms");
		
		serializer.startTag(null, "id");
		serializer.text(smsInfo.getId());
		serializer.endTag(null, "id");
		
		serializer.startTag(null, "address");
		serializer.text(smsInfo.getAddress());
		serializer.endTag(null, "address");
		
		serializer.startTag(null, "date");
		serializer.text(smsInfo.getDate());
		serializer.endTag(null, "date");
		
		serializer.startTag(null, "type");
		serializer.text(smsInfo.getType()+"");
		serializer.endTag(null, "type");
		
		serializer.startTag(null, "body");
		serializer.text(smsInfo.getBody());
		serializer.endTag(null, "body");
		
		
		serializer.endTag(null, "sms");
	}
	serializer.endTag(null, "smss");
	serializer.endDocument();
	fos.flush();
	fos.close();
	Looper.prepare();
	Toast.makeText(getApplicationContext(), "备份完成", 1).show();
	Looper.loop();
	
} catch (Exception e) {
	e.printStackTrace();
	Looper.prepare();
	Toast.makeText(getApplicationContext(), "备份失败", 1).show();
	Looper.loop();
}

说明：1.new一个文件，将数据存放到文件中。
      2.用XmlSerializer将数据写到xml文件中。
应用：1.短信备份
      2.通讯录本地备份
      3.等等备份