Android学习（22） -- 数据存储之使用xml保存数据

在实际开发中，经常会用到xml来存储数据，比如：备份手机联系人，备份短信等等。我们以备份短信为例来讲解下xml的使用。

要想备份短信，那么我们就需要创建一个操作短信的JavaBean。如代码：

public class Message {

	private String body;<span style="white-space:pre">	</span>//短信内容
	private String date;    //时间
	private String address; //地址
	private String type;    //类型 1是接受 2是发送
	public String getBody() {
		return body;
	}
	public void setBody(String body) {
		this.body = body;
	}
	public String getDate() {
		return date;
	}
	public void setDate(String date) {
		this.date = date;
	}
	public String getAddress() {
		return address;
	}
	public void setAddress(String address) {
		this.address = address;
	}
	public String getType() {
		return type;
	}
	public void setType(String type) {
		this.type = type;
	}
	public Message(String body, String date, String address, String type) {
		super();
		this.body = body;
		this.date = date;
		this.address = address;
		this.type = type;
	}
	
	
}

接下来，我们在Activity中编写一个点击事件用于存储短信（为了方便理解xml操作，我们使用模拟的数据的方式进行演示）。

public class MainActivity extends Activity {

	List<Message> smsList;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		//虚拟10条短信
		smsList = new ArrayList<Message>();
		for(int i = 0; i < 10; i++){
			Message sms = new Message("模拟数据 " + i, System.currentTimeMillis() + "", "133"+i+i, "1");
			smsList.add(sms);
		}
	}

	public void click(View v){
		if(Environment .getExternalStorageState().equals(Environment.MEDIA_MOUNTED) ){
			//在内存中把xml备份短信的格式拼接出来
			StringBuffer sb = new StringBuffer();
			sb.append("<?xml version='1.0' encoding='utf-8' standalone='yes' ?>");
			sb.append("<messages>");
			for (Message sms : smsList) {
				sb.append("<sms>");
				
				sb.append("<body>");
				sb.append(sms.getBody());
				sb.append("</body>");
				
				sb.append("<date>");
				sb.append(sms.getDate());
				sb.append("</date>");
				
				sb.append("<type>");
				sb.append(sms.getType());
				sb.append("</type>");
				
				sb.append("<address>");
				sb.append(sms.getAddress());
				sb.append("</address>");
				
				sb.append("</sms>");
			}
			sb.append("</messages>");
			
			File file = new File(Environment .getExternalStorageDirectory(),"sms.xml");

			try {
				FileOutputStream fos = new FileOutputStream(file);
				fos.write(sb.toString().getBytes());
				fos.close();
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}else{
			Toast.makeText(SDcardActivity.this,"此时SDcard不存在或者不能进行读写操作", Toast.LENGTH_SHORT).show();
		}
	}

}

原文链接：https://blog.csdn.net/idiandi/article/details/51155823