使用内容提供者和xml备份联系人

1、通过内容提供者获取联系人信息

 package com.ithaimazyh.readcontact;

 import java.util.ArrayList;
 import java.util.List;

 import com.ithaimazyh.readcontact.domain.PersonInfo;
 import com.ithaimazyh.readcontact.service.SavePersonsInfo;

 import android.net.Uri;
 import android.os.Bundle;
 import android.app.Activity;
 import android.content.ContentResolver;
 import android.database.Cursor;
 import android.view.Menu;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.widget.Button;

 public class MainActivity extends Activity {

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         Button rp = (Button) findViewById(R.id.rp);
         rp.setOnClickListener(new OnClickListener() {

             @Override
             public void onClick(View v) {
                 // TODO Auto-generated method stub
                 //System.out.println("hello world");
                 readContact();
             }
         });
     }

     public void readContact(){
         Uri uri = Uri.parse("content://com.android.contacts/raw_contacts");
         Uri data_uri = Uri.parse("content://com.android.contacts/data");

         ContentResolver resolver = getContentResolver();
         Cursor cursor = resolver.query(uri, null, null, null, null);

         /*String[] names = cursor.getColumnNames();
         for(String name : names){
             System.out.println(name);
         }*/
         List<PersonInfo> persons = new ArrayList<PersonInfo>();
         while(cursor.moveToNext()){
             String contact_id = cursor.getString(cursor.getColumnIndex("contact_id"));
             if(contact_id != null){
                 String name = "";
                 String phoneNum = "";
                 Cursor datacursor = resolver.query(data_uri, null, "raw_contact_id=?", new String[]{contact_id}, null);
                 while(datacursor.moveToNext()){
                     String data1 = datacursor.getString(datacursor.getColumnIndex("data1"));
                     String mimetype = datacursor.getString(datacursor.getColumnIndex("mimetype"));

                     //System.out.println(data1 + "-----" + mimetype);
                     if(mimetype.equals("vnd.android.cursor.item/name")){
                         name = data1;
                     }else if(mimetype.equals("vnd.android.cursor.item/phone_v2")){
                         phoneNum = data1;
                     }else{

                     }
                 }

                 if(name != null && phoneNum != null){
                     PersonInfo person = new PersonInfo(name,phoneNum);
                     persons.add(person);
                 }
                 datacursor.close();
                 //System.out.print("=========================");
             }
         }
         cursor.close();

         SavePersonsInfo.savePersonsInfo(this, persons);
     /*    Cursor datacursor = resolver.query(data_uri, null, null, null, null);
         String[] names = datacursor.getColumnNames();
         for(String name : names){
             System.out.println(name);
         }*/
     }
 }

2、权限配置

  <uses-permission android:name="android.permission.READ_CONTACTS"/>
    <uses-permission android:name="android.permission.WRITE_CONTACTS"/>

3、通过xml保存联系人信息

 package com.ithaimazyh.readcontact.service;

 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.util.List;

 import org.xmlpull.v1.XmlSerializer;

 import com.ithaimazyh.readcontact.domain.PersonInfo;

 import android.content.Context;
 import android.os.Environment;
 import android.util.Xml;
 import android.widget.Toast;

 public class SavePersonsInfo {
     public static boolean savePersonsInfo(Context context, List<PersonInfo> persons){
         if(persons.size() > 0){
             try {
                 File file = new File(Environment.getExternalStorageDirectory(),"persons.xml");
                 FileOutputStream fos = new FileOutputStream(file);
                 XmlSerializer serializer = Xml.newSerializer();
                 serializer.setOutput(fos, "utf-8");
                 serializer.startDocument("utf-8", true);
                 serializer.startTag(null, "persons");

                 for(PersonInfo person : persons){
                     serializer.startTag(null, "person");

                     serializer.startTag(null, "name");
                     serializer.text(person.getName());
                     serializer.endTag(null, "name");

                     serializer.startTag(null, "phoneNum");
                     serializer.text(person.getPhoneNum());
                     serializer.endTag(null, "phoneNum");

                     serializer.endTag(null, "person");
                 }

                 serializer.endTag(null, "persons");
                 serializer.endDocument();

                 fos.close();
                 Toast.makeText(context, "保存xml成功", 0).show();
             } catch (Exception e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
                 Toast.makeText(context, "保存xml失败", 0).show();
             }
         }
         return true;
     }
 }

4、把文件保存在外存，权限配置

 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

5、person类

 package com.ithaimazyh.readcontact.domain;

 public class PersonInfo {
     private String name;
     private String phoneNum;

     public PersonInfo() {

     }

     public PersonInfo(String name, String phoneNum) {
         this.name = name;
         this.phoneNum = phoneNum;
     }
     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public String getPhoneNum() {
         return phoneNum;
     }
     public void setPhoneNum(String phoneNum) {
         this.phoneNum = phoneNum;
     }
 }

注意：如果在查询数据时不知道列名，可以通过如下方法打印来了解

String[] columnNames = datacursor.getColumnNames();