添加注释

Notes-master/src/net/micode/notes/data/Contact.java

@@ -2,16 +2,11 @@
  * 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
+ * 您可以在遵守License的前提下使用本文件
+ * 具体License内容可查阅：http://www.apache.org/licenses/LICENSE-2.0
  *
- *        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.
+ * 软件按"原样"分发，不提供任何形式的明示或暗示的保证
+ * 详见License中关于权限和限制的具体条款
  */
 
 package net.micode.notes.data;
@@ -25,49 +20,74 @@ import android.util.Log;
 
 import java.util.HashMap;
 
+/**
+ * 联系人信息查询工具类
+ * 提供通过电话号码获取联系人姓名的功能
+ * 包含缓存机制以优化重复查询性能
+ */
 public class Contact {
+    // 联系人缓存：键为电话号码，值为对应的联系人姓名
     private static HashMap<String, String> sContactCache;
     private static final String TAG = "Contact";
 
+    // 联系人查询条件模板
+    // 使用PHONE_NUMBERS_EQUAL函数匹配电话号码，限定MIME类型为电话类型
     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 "
+            + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'"
+            + " AND " + Data.RAW_CONTACT_ID + " IN "
             + "(SELECT raw_contact_id "
             + " FROM phone_lookup"
             + " WHERE min_match = '+')";
 
+    /**
+     * 根据电话号码查询对应的联系人姓名
+     * 
+     * @param context 应用上下文，用于获取ContentResolver
+     * @param phoneNumber 待查询的电话号码
+     * @return 匹配的联系人姓名，未找到则返回null
+     */
     public static String getContact(Context context, String phoneNumber) {
-        if(sContactCache == null) {
+        // 初始化缓存（懒加载方式）
+        if (sContactCache == null) {
             sContactCache = new HashMap<String, String>();
         }
 
-        if(sContactCache.containsKey(phoneNumber)) {
+        // 优先从缓存中获取结果，避免重复查询
+        if (sContactCache.containsKey(phoneNumber)) {
             return sContactCache.get(phoneNumber);
         }
 
+        // 构建适配查询的电话号码格式（转换为CallerID匹配格式）
         String selection = CALLER_ID_SELECTION.replace("+",
                 PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));
+        
+        // 执行联系人查询（查询联系人显示名称）
         Cursor cursor = context.getContentResolver().query(
-                Data.CONTENT_URI,
-                new String [] { Phone.DISPLAY_NAME },
-                selection,
-                new String[] { phoneNumber },
-                null);
+                Data.CONTENT_URI,            // 联系人数据URI
+                new String[] { Phone.DISPLAY_NAME },  // 仅查询显示名称
+                selection,                    // 动态生成的查询条件
+                new String[] { phoneNumber }, // 查询参数（电话号码）
+                null);                        // 不指定排序
 
+        // 处理查询结果
         if (cursor != null && cursor.moveToFirst()) {
             try {
+                // 提取联系人姓名并存入缓存
                 String name = cursor.getString(0);
                 sContactCache.put(phoneNumber, name);
                 return name;
             } catch (IndexOutOfBoundsException e) {
-                Log.e(TAG, " Cursor get string error " + e.toString());
+                // 处理列索引越界异常（防御性编程）
+                Log.e(TAG, "Cursor获取字符串错误: " + e.toString());
                 return null;
             } finally {
+                // 确保关闭Cursor以释放资源
                 cursor.close();
             }
         } else {
-            Log.d(TAG, "No contact matched with number:" + phoneNumber);
+            // 记录未匹配到联系人的日志
+            Log.d(TAG, "未找到匹配号码: " + phoneNumber);
             return null;
         }
     }
-}
+}