本节学习，保存系统短信到SD卡中。既然是要保存系统短信到SD卡中，前提是先要拿到系统的短信，关于如何读取系统的短信，请看我的关于ContentProvider文章：
Android 四大组件学习之ContentProvider三
既然知道了任务的目的，那我们就直接实现。我们先将系统的短信读出，然后保存到xml文件中，然后将xml文件写到sd卡中。
1： 先将系统短信读出
代码语言：javascript复制//得到ContentResolver
ContentResolver cr = getContentResolver();
//查询系统的短信，只需要查询我们关心的字段
Cursor cursor = cr.query(Uri.parse("content://sms"), new String[]{"address", "date", "type", "body"},
null, null, null);
//取出查询到的信息
while(cursor.moveToNext())
{
String address = cursor.getString(cursor.getColumnIndex("address"));
String date = cursor.getString(cursor.getColumnIndex("date"));
String type = cursor.getString(cursor.getColumnIndex("type"));
String body = cursor.getString(cursor.getColumnIndex("body"));
//将每条短信放入List集合中
Message msg = new Message(address, date, type, body);
list.add(msg);
}2： 其中Message是我定义的关于短信的类
代码语言：javascript复制public class Message {
private String address; //号码
private String date; //时间
private String type; //类型：1为发生，2为接受
private String body; //短信内容
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getDate() {
return date;
}
public void setDate(String date) {
this.date = date;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public String getBody() {
return body;
}
public void setBody(String body) {
this.body = body;
}
@Override
public String toString() {
return "Message [address=" address ", date=" date ", type="
type ", body=" body "]";
}
public Message(String address, String date, String type, String body) {
super();
this.address = address;
this.date = date;
this.type = type;
this.body = body;
}
}3：将短信的内容拼接为一个xml文件
代码语言：javascript复制//使用stringBuffer将短信内容拼接为xml文件
StringBuffer sBuffer = new StringBuffer();
//xml文件的头
sBuffer.append("<?xml version='1.0' encoding='utf-8' standalone='yes' ?>");
//xml文件的开始标签
sBuffer.append("<Message>");
for (Message sms : list) {
sBuffer.append("<sms>");
//插入联系人号码字段
sBuffer.append("<address>");
sBuffer.append(sms.getAddress());
sBuffer.append("</address>");
//插入联系人类型字段
sBuffer.append("<type>");
sBuffer.append(sms.getType());
sBuffer.append("</type>");
//插入消息的内容
sBuffer.append("<body>");
sBuffer.append(sms.getBody());
sBuffer.append("</body>");
//插入消息的时间
sBuffer.append("<date>");
sBuffer.append(sms.getDate());
sBuffer.append("</date>");
sBuffer.append("</sms>");
}
//结束标签
sBuffer.append("</Message>");4：将xml文件写入到sd卡中
代码语言：javascript复制File file = new File("sdcard/sms.xml");
try {
FileOutputStream fos = new FileOutputStream(file);
fos.write(sBuffer.toString().getBytes());
fos.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}整个代码流程为：
代码语言：javascript复制public class MainActivity extends Activity {
List<Message> list;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
list = new ArrayList<Message>();
}
public void storageMessage(View v)
{
//得到ContentResolver
ContentResolver cr = getContentResolver();
//查询系统的短信，只需要查询我们关心的字段
Cursor cursor = cr.query(Uri.parse("content://sms"), new String[]{"address", "date", "type", "body"},
null, null, null);
//取出查询到的信息
while(cursor.moveToNext())
{
String address = cursor.getString(cursor.getColumnIndex("address"));
String date = cursor.getString(cursor.getColumnIndex("date"));
String type = cursor.getString(cursor.getColumnIndex("type"));
String body = cursor.getString(cursor.getColumnIndex("body"));
//将每条短信放入List集合中
Message msg = new Message(address, date, type, body);
list.add(msg);
}
//使用stringBuffer将短信内容拼接为xml文件
StringBuffer sBuffer = new StringBuffer();
//xml文件的头
sBuffer.append("<?xml version='1.0' encoding='utf-8' standalone='yes' ?>");
//xml文件的开始标签
sBuffer.append("<Message>");
for (Message sms : list) {
sBuffer.append("<sms>");
//插入联系人号码字段
sBuffer.append("<address>");
sBuffer.append(sms.getAddress());
sBuffer.append("</address>");
//插入联系人类型字段
sBuffer.append("<type>");
sBuffer.append(sms.getType());
sBuffer.append("</type>");
//插入消息的内容
sBuffer.append("<body>");
sBuffer.append(sms.getBody());
sBuffer.append("</body>");
//插入消息的时间
sBuffer.append("<date>");
sBuffer.append(sms.getDate());
sBuffer.append("</date>");
sBuffer.append("</sms>");
}
//结束标签
sBuffer.append("</Message>");
File file = new File("sdcard/sms.xml");
try {
FileOutputStream fos = new FileOutputStream(file);
fos.write(sBuffer.toString().getBytes());
fos.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}当点击按钮保存系统短信后，可以在sd卡的目录下找到sms.xml文件
导出xml文件打开：
以其中一条短信为例：
ok。关于如何备份短信就讲到这里
