/*
 * 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.
 */
/*这段代码是一个用于获取联系人信息的工具类。主要功能是根据电话号码查询对应的联系人名称。*/
package net.micode.notes.data;
/**/
import android.content.Context;
import android.database.Cursor;
import android.provider.ContactsContract.CommonDataKinds.Phone;
import android.provider.ContactsContract.Data;
import android.telephony.PhoneNumberUtils;
import android.util.Log;

import java.util.HashMap;

public class Contact {
    private static HashMap<String, String> sContactCache;
    /*sContactCache是一个哈希映射，缓存已经查询过的联系人*/
    private static final String TAG = "Contact";

    private static final String CALLER_ID_SELECTION = "PHONE_NUMBERS_EQUAL(" + Phone.NUMBER
    + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'"
    + " 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) {
            sContactCache = new HashMap<String, String>();
        }

        if(sContactCache.containsKey(phoneNumber)) {
            return sContactCache.get(phoneNumber);
        }
        /*检查是否包含了需要查询的变量*/

        String selection = CALLER_ID_SELECTION.replace("+",
                PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));
        Cursor cursor = context.getContentResolver().query(
                Data.CONTENT_URI,
                new String [] { Phone.DISPLAY_NAME },
                selection,
                new String[] { phoneNumber },
                null);
/*如果sContactCache中不包含该电话号码，则构建查询条件selection，将电话号码转换为最小匹配模式，并替换查询语句中的占位符。
 */
        if (cursor != null && cursor.moveToFirst()) {
            try {
                String name = cursor.getString(0);
                sContactCache.put(phoneNumber, name);
                return name;
            } catch (IndexOutOfBoundsException e) {
                Log.e(TAG, " Cursor get string error " + e.toString());
                return null;
            } finally {
                cursor.close();
            }
        } else {
            Log.d(TAG, "No contact matched with number:" + phoneNumber);
            return null;
        }
        /*接下来通过内容解析器ContentResolver查询联系人数据表Data.CONTENT_URI，查询列为联系人名称Phone.DISPLAY_NAME。

        查询条件为电话号码与查询语句中的电话号码相等，并且数据类型为电话号码类型。

        如果查询结果不为空且移动到第一条记录，则从查询结果中获取联系人名称，并将电话号码和联系人名称存入sContactCache中。

        最后关闭查询结果的游标并返回联系人名称。*/
    }
    /*该类中的方法getContact()接受一个上下文Context和一个电话号码phoneNumber作为参数，返回与该电话号码相关联的联系人名称。*/

}