/*
 * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

 package net.micode.notes.data;      //将该类放在data包中

 import android.content.Context; //有关应用程序环境的全局信息的接口。
 import android.database.Cursor; //此接口提供对数据库查询返回的结果集的随机读写访问。
 import android.provider.ContactsContract.CommonDataKinds.Phone;//用于通讯中的类，读取电话号码
 import android.provider.ContactsContract.Data;//提供的常量
 import android.telephony.PhoneNumberUtils;//获取手机短信
 import android.util.Log;
 
 import java.util.HashMap;      //在util包中的一个类
 
 public class Contact {          //声明一个公有类
     private static HashMap<String, String> sContactCache;           //一个静态的hashmap的对象，且数据类型是两个string类
     private static final String TAG = "Contact";            //一个静态常量的string类型
 
     private static final String CALLER_ID_SELECTION = "PHONE_NUMBERS_EQUAL(" + Phone.NUMBER
     + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'"        //使得MIMETYPE获得电话
     + " AND " + Data.RAW_CONTACT_ID + " IN "
             + "(SELECT raw_contact_id "
             + " FROM phone_lookup"
             + " WHERE min_match = '+')";
 
     public static String getContact(Context context, String phoneNumber) {
         if(sContactCache == null) {//判断scontactcache是否为空
             sContactCache = new HashMap<String, String>();//如果为空，则为scontactcache申请空间
         }
 
         if(sContactCache.containsKey(phoneNumber)) {//检查phonenumber是否存在指定的映射关系，返回一个boolean类型的数据
             return sContactCache.get(phoneNumber);//返回改key所对应的value值
         }
 
         String selection = CALLER_ID_SELECTION.replace("+",         //replace是查找并替换，将+号用
                 PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));         //构建一个查询时，生成后七位号码
         Cursor cursor = context.getContentResolver().query(             //得到一个context的对象并进行数据查询
                 Data.CONTENT_URI,          //对应的是联系人数据表，在数据表中查找数据
                 new String [] { Phone.DISPLAY_NAME },//联系人名称
                 selection,
                 new String[] { phoneNumber },
                 null);
 
         if (cursor != null && cursor.moveToFirst()) {      //cursor不为空，且查询结果不为空
             try {
                 String name = cursor.getString(0);         //获得第一个列值
                 sContactCache.put(phoneNumber, name);      //容器中放入号码和姓名
                 return name;                               //返回得到的名字
             } catch (IndexOutOfBoundsException e) {
                 Log.e(TAG, " Cursor get string error " + e.toString());        //提示获取失败
                 return null;                                   //如果发生异常返回空
             } finally {
                 cursor.close();                            //将cursor关闭
             }
         } else {                                           //没有查找到姓名
             Log.d(TAG, "No contact matched with number:" + phoneNumber);   //错误提示
             return null;           //返回空
         }
     }
 }