ReadMiNotes/标注/Contact.java

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;
// 定义一个Contact类
public class Contact {
    // 声明一个HashMap类型的静态变量sContactCache
    private static HashMap<String, String> sContactCache;
    // 声明一个String类型的静态变量TAG
    private static final String TAG = "Contact";

    // 声明一个String类型的静态变量CALLER_ID_SELECTION
    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 = '+')";

    // 定义一个静态方法getContact，参数为context和phoneNumber
    public static String getContact(Context context, String phoneNumber) {
        // 如果sContactCache为空，则初始化sContactCache
        if(sContactCache == null) {
            sContactCache = new HashMap<String, String>();
        }

        // 检查缓存中是否有该号码的联系人
        if(sContactCache.containsKey(phoneNumber)) {
            return sContactCache.get(phoneNumber);
        }

        // 查询数据库中是否有该号码的联系人
        String selection = CALLER_ID_SELECTION.replace("+",
                PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));
        // 根据电话号码查询联系人
        Cursor cursor = context.getContentResolver().query(
                Data.CONTENT_URI,
                new String [] { Phone.DISPLAY_NAME },
                selection,
                new String[] { phoneNumber },
                null);

       if (cursor != null && cursor.moveToFirst()) {
            try {
                // 获取联系人名字
                String name = cursor.getString(0);
                // 将联系人名字存入缓存
                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;
        }
    }
}