diff --git a/src/Notes-master/.idea/sonarlint/issuestore/0/2/023468cfdd0b71d4098903b9070e364658e2fbcf b/src/Notes-master/.idea/sonarlint/issuestore/0/2/023468cfdd0b71d4098903b9070e364658e2fbcf
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index 0000000..fb72d00
--- /dev/null
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+
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+V	java:S125"<This block of commented-out lines of code should be removed.(͛�������
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+V	java:S125Q"<This block of commented-out lines of code should be removed.(��������
+e
+java:S1874^"JDon't override a deprecated method or explicitly mark it as "@Deprecated".(ë�������
+e
+java:S1874f"JDon't override a deprecated method or explicitly mark it as "@Deprecated".(�ች�����
\ No newline at end of file
diff --git a/src/Notes-master/.idea/sonarlint/issuestore/3/a/3aac5305cb73bfbdeb8078cd264d04323fa80e92 b/src/Notes-master/.idea/sonarlint/issuestore/3/a/3aac5305cb73bfbdeb8078cd264d04323fa80e92
new file mode 100644
index 0000000..e69de29
diff --git a/src/Notes-master/.idea/sonarlint/issuestore/4/5/4529b3a97b0f3b19b895aa06f23bed63ff38a312 b/src/Notes-master/.idea/sonarlint/issuestore/4/5/4529b3a97b0f3b19b895aa06f23bed63ff38a312
new file mode 100644
index 0000000..14b3293
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+java:S2093�"*Change this "try" to a try-with-resources.(���������
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\ No newline at end of file
diff --git a/src/Notes-master/.idea/sonarlint/issuestore/a/b/ab153b0256bc5f6c194e188cec0b8e327e347a90 b/src/Notes-master/.idea/sonarlint/issuestore/a/b/ab153b0256bc5f6c194e188cec0b8e327e347a90
new file mode 100644
index 0000000..d470860
--- /dev/null
+++ b/src/Notes-master/.idea/sonarlint/issuestore/a/b/ab153b0256bc5f6c194e188cec0b8e327e347a90
@@ -0,0 +1,43 @@
+
+o
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+java:S2293^"YReplace the type specification in this constructor call with the diamond operator ("<>").(���������
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+java:S2293_"YReplace the type specification in this constructor call with the diamond operator ("<>").(���������
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+java:S2293a"YReplace the type specification in this constructor call with the diamond operator ("<>").(����
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+java:S2293c"YReplace the type specification in this constructor call with the diamond operator ("<>").(���������
+]
+java:S1192�"FDefine a constant instead of duplicating this literal " DESC" 3 times.(��Ա
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+java:S1066�"/Merge this if statement with the enclosing one.(���������
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+java:S1066�"/Merge this if statement with the enclosing one.(˼֓�����
+i
+java:S3776�"RRefactor this method to reduce its Cognitive Complexity from 29 to the 15 allowed.(�þ�
+I
+java:S1905�"-Remove this unnecessary cast to "JSONObject".(｀������
+C
+java:S1905�"-Remove this unnecessary cast to "JSONObject".(؛�
+i
+java:S3776�"RRefactor this method to reduce its Cognitive Complexity from 28 to the 15 allowed.(���
+n
+java:S3776�"RRefactor this method to reduce its Cognitive Complexity from 41 to the 15 allowed.(�˰������
+n
+java:S3776�"RRefactor this method to reduce its Cognitive Complexity from 34 to the 15 allowed.(��ɸ�����
+5
+java:S2129�"Remove this "Long" constructor(ϭ��
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+java:S1874�",Remove this use of "Long"; it is deprecated.(ϭ��
+n
+java:S3776�"RRefactor this method to reduce its Cognitive Complexity from 20 to the 15 allowed.(ƶؠ�����
+G
+java:S1172�"+Remove this unused method parameter "node".(ƶؠ�����
+C
+java:S1905�"'Remove this unnecessary cast to "Node".(���������
+>
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\ No newline at end of file
diff --git a/src/Notes-master/.idea/sonarlint/issuestore/c/1/c182d0c9c237ea8a46a92ccaae9bb5c751923a88 b/src/Notes-master/.idea/sonarlint/issuestore/c/1/c182d0c9c237ea8a46a92ccaae9bb5c751923a88
new file mode 100644
index 0000000..e69de29
diff --git a/src/Notes-master/.idea/sonarlint/issuestore/f/0/f087b1ba1b9c91b7293fea0fb071eaed62a42137 b/src/Notes-master/.idea/sonarlint/issuestore/f/0/f087b1ba1b9c91b7293fea0fb071eaed62a42137
new file mode 100644
index 0000000..86a5121
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+
+>
+java:S1604/"(Make this anonymous inner class a lambda(�ю�
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+`
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+L
+java:S2696/"6Make the enclosing method "static" or remove this set.(�ю�
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+E
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+L
+java:S2696C"6Make the enclosing method "static" or remove this set.(����
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diff --git a/src/Notes-master/.idea/sonarlint/securityhotspotstore/0/2/023468cfdd0b71d4098903b9070e364658e2fbcf b/src/Notes-master/.idea/sonarlint/securityhotspotstore/0/2/023468cfdd0b71d4098903b9070e364658e2fbcf
new file mode 100644
index 0000000..e69de29
diff --git a/src/Notes-master/.idea/sonarlint/securityhotspotstore/3/a/3aac5305cb73bfbdeb8078cd264d04323fa80e92 b/src/Notes-master/.idea/sonarlint/securityhotspotstore/3/a/3aac5305cb73bfbdeb8078cd264d04323fa80e92
new file mode 100644
index 0000000..e69de29
diff --git a/src/Notes-master/.idea/sonarlint/securityhotspotstore/4/5/4529b3a97b0f3b19b895aa06f23bed63ff38a312 b/src/Notes-master/.idea/sonarlint/securityhotspotstore/4/5/4529b3a97b0f3b19b895aa06f23bed63ff38a312
new file mode 100644
index 0000000..e69de29
diff --git a/src/Notes-master/.idea/sonarlint/securityhotspotstore/a/b/ab153b0256bc5f6c194e188cec0b8e327e347a90 b/src/Notes-master/.idea/sonarlint/securityhotspotstore/a/b/ab153b0256bc5f6c194e188cec0b8e327e347a90
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index 0000000..e69de29
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new file mode 100644
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diff --git a/src/Notes-master/.idea/sonarlint/securityhotspotstore/f/0/f087b1ba1b9c91b7293fea0fb071eaed62a42137 b/src/Notes-master/.idea/sonarlint/securityhotspotstore/f/0/f087b1ba1b9c91b7293fea0fb071eaed62a42137
new file mode 100644
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diff --git a/src/Notes-master/app/src/main/java/net/micode/notes/data/data/Contact.java b/src/Notes-master/app/src/main/java/net/micode/notes/data/data/Contact.java
new file mode 100644
index 0000000..e35fb81
--- /dev/null
+++ b/src/Notes-master/app/src/main/java/net/micode/notes/data/data/Contact.java
@@ -0,0 +1,92 @@
+/*
+ * 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;
+
+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;
+
+/*
+*功能描述:创建联系人数据库
+*/
+public class Contact {//联系人
+    private static HashMap<String, String> sContactCache;// sContactCache 是一个静态的 HashMap，用于缓存联系人信息，用于缓存联系人信息的HashMap
+    private static final String TAG = "Contact";// TAG 日志标签
+
+    // 定义字符串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 = '+')";// 定义查询条件的字符串
+
+    /*
+    * 功能描述：用于获取联系人信息。
+    * 输入参数：接受一个上下文参数和一个电话号码参数
+    * 返回结果：返回与该电话号码对应的联系人名字
+    */
+    public static String getContact(Context context, String phoneNumber) {
+        if(sContactCache == null) {// 如果联系人缓存为空
+            sContactCache = new HashMap<String, String>();// 初始化联系人缓存
+        }
+
+        /*
+        * 查找HashMap中是否已有phoneNumber信息
+        */
+        if(sContactCache.containsKey(phoneNumber)) {// 如果在缓存中找到了电话号码对应的联系人信息
+            return sContactCache.get(phoneNumber);// 直接从缓存中返回联系人信息
+        }
+
+        String selection = CALLER_ID_SELECTION.replace("+",
+                PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));//PhoneNumberUtils.toCallerIDMinMatch() 方法将电话号码转换为最小匹配模式，构建带有电话号码的查询条件
+        /*
+        * 查找数据库中phoneNumber的信息
+        * */
+        Cursor cursor = context.getContentResolver().query(
+                Data.CONTENT_URI,// 联系人数据的URI
+                new String [] { Phone.DISPLAY_NAME },// 要查询的字段，这里是联系人名字
+                selection,// 查询条件
+                new String[] { phoneNumber },// 查询条件中的占位符对应的值
+                null);// 不指定排序
+        /*
+        * 判定查询结果，如果查询结果不为空且移动到第一条记录，（moveToFirst()返回第一条记录）
+        * */
+        if (cursor != null && cursor.moveToFirst()) {
+            try {// 找到相关信息
+                String name = cursor.getString(0);// 获取联系人名字
+                sContactCache.put(phoneNumber, name);// 将联系人名字放入缓存
+                return name;// 返回联系人名字
+
+            } catch (IndexOutOfBoundsException e) {// 捕获IndexOutOfBoundsException异常
+                Log.e(TAG, " Cursor get string error " + e.toString());// 记录异常日志
+                return null;// 返回null
+            } finally {
+                cursor.close();// 关闭查询结果的Cursor
+            }
+            // 未找到相关信息
+        } else {
+            Log.d(TAG, "No contact matched with number:" + phoneNumber);// 记录未找到联系人信息的日志
+            return null;
+        }
+    }
+}
diff --git a/src/Notes-master/app/src/main/java/net/micode/notes/data/data/Notes.java b/src/Notes-master/app/src/main/java/net/micode/notes/data/data/Notes.java
new file mode 100644
index 0000000..6e77934
--- /dev/null
+++ b/src/Notes-master/app/src/main/java/net/micode/notes/data/data/Notes.java
@@ -0,0 +1,310 @@
+/*
+ * 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;
+
+import android.net.Uri;
+
+/*
+*功能描述：用于存储便签数据，包含了一条便签的各种属性，如标题、内容、创建时间、修改时间等
+*/
+public class Notes {
+    public static final String AUTHORITY = "micode_notes"; // 定义内容提供器的权限
+    public static final String TAG = "Notes";// 定义日志标签
+
+    //以下三个常量对NoteColumns.TYPE的值进行设置，对应不同的便签类型
+    public static final int TYPE_NOTE     = 0;// 便签类型为普通便签
+    public static final int TYPE_FOLDER   = 1;// 便签类型为文件夹
+    public static final int TYPE_SYSTEM   = 2;// 便签类型为系统文件夹
+
+    /**
+     * Following IDs are system folders' identifiers
+     * {@link Notes#ID_ROOT_FOLDER } is default folder
+     * {@link Notes#ID_TEMPARAY_FOLDER } is for notes belonging no folder
+     * {@link Notes#ID_CALL_RECORD_FOLDER} is to store call records
+     */
+
+    /*
+    * 系统文件夹的标识符
+    * */
+    public static final int ID_ROOT_FOLDER = 0;// 默认文件夹
+    public static final int ID_TEMPARAY_FOLDER = -1;// 没有所属文件夹的便签
+    public static final int ID_CALL_RECORD_FOLDER = -2;// 存储通话记录的文件夹
+    public static final int ID_TRASH_FOLER = -3;// 垃圾箱文件夹
+
+    /*
+    * 定义设置中的参数常量
+    * */
+    public static final String INTENT_EXTRA_ALERT_DATE = "net.micode.notes.alert_date";// 提醒日期
+    public static final String INTENT_EXTRA_BACKGROUND_ID = "net.micode.notes.background_color_id";// 背景颜色ID
+    public static final String INTENT_EXTRA_WIDGET_ID = "net.micode.notes.widget_id";// Widget ID
+    public static final String INTENT_EXTRA_WIDGET_TYPE = "net.micode.notes.widget_type";// Widget类型
+    public static final String INTENT_EXTRA_FOLDER_ID = "net.micode.notes.folder_id";// 文件夹ID
+    public static final String INTENT_EXTRA_CALL_DATE = "net.micode.notes.call_date"; // 通话日期
+
+    /*
+    * 定义Widget类型常量
+    * */
+    public static final int TYPE_WIDGET_INVALIDE      = -1;// 无效的Widget类型
+    public static final int TYPE_WIDGET_2X            = 0;// 2x2大小的Widget
+    public static final int TYPE_WIDGET_4X            = 1;// 4x4大小的Widget
+
+    /*
+    * 定义便签数据类型常量
+    * */
+    public static class DataConstants {
+        public static final String NOTE = TextNote.CONTENT_ITEM_TYPE;// 文本便签数据类型
+        public static final String CALL_NOTE = CallNote.CONTENT_ITEM_TYPE;// 电话便签数据类型
+    }
+
+    /**
+     * Uri to query all notes and folders
+     */
+    public static final Uri CONTENT_NOTE_URI = Uri.parse("content://" + AUTHORITY + "/note");// 查询所有便签和文件夹的标识符
+
+    /**
+     * Uri to query data
+     */
+    public static final Uri CONTENT_DATA_URI = Uri.parse("content://" + AUTHORITY + "/data");// 查询数据的标识符
+
+    /*
+     * 功能描述：定义NoteColumns接口数据的常量，用于创建数据库表头
+     */
+    public interface NoteColumns {
+        /**
+         * The unique ID for a row
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ID = "_id";// 行的唯一标识符
+
+        /**
+         * The parent's id for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String PARENT_ID = "parent_id";// 父级的ID
+
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date";// 创建日期
+
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date";// 最后修改日期
+
+
+        /**
+         * Alert date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ALERTED_DATE = "alert_date";// 提醒日期
+
+        /**
+         * Folder's name or text content of note
+         * <P> Type: TEXT </P>
+         */
+        public static final String SNIPPET = "snippet";// 文件夹名称或便签的文本内容
+
+        /**
+         * Note's widget id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String WIDGET_ID = "widget_id";// 便签的Widget ID
+
+        /**
+         * Note's widget type
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String WIDGET_TYPE = "widget_type";// 便签的Widget类型
+
+        /**
+         * Note's background color's id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String BG_COLOR_ID = "bg_color_id";// 便签的背景颜色ID
+
+        /**
+         * For text note, it doesn't has attachment, for multi-media
+         * note, it has at least one attachment
+         * <P> Type: INTEGER </P>
+         */
+        public static final String HAS_ATTACHMENT = "has_attachment";// 是否有附件
+
+        /**
+         * Folder's count of notes
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String NOTES_COUNT = "notes_count";// 文件夹中的便签数量
+
+        /**
+         * The file type: folder or note
+         * <P> Type: INTEGER </P>
+         */
+        public static final String TYPE = "type";// 文件类型：文件夹或便签
+
+        /**
+         * The last sync id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String SYNC_ID = "sync_id";// 最后同步的ID
+
+        /**
+         * Sign to indicate local modified or not
+         * <P> Type: INTEGER </P>
+         */
+        public static final String LOCAL_MODIFIED = "local_modified";// 标识是否本地修改
+
+        /**
+         * Original parent id before moving into temporary folder
+         * <P> Type : INTEGER </P>
+         */
+        public static final String ORIGIN_PARENT_ID = "origin_parent_id";// 移动到临时文件夹之前的原始父级ID
+
+        /**
+         * The gtask id
+         * <P> Type : TEXT </P>
+         */
+        public static final String GTASK_ID = "gtask_id";// Google任务ID
+
+        /**
+         * The version code
+         * <P> Type : INTEGER (long) </P>
+         */
+        public static final String VERSION = "version";// 版本号
+    }
+
+    /*
+    * 功能描述：定义DataColumns接口数据的常量，用于创建数据库表头
+    */
+    public interface DataColumns {
+        /**
+         * The unique ID for a row
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ID = "_id";// 标识符
+
+        /**
+         * The MIME type of the item represented by this row.
+         * <P> Type: Text </P>
+         */
+        public static final String MIME_TYPE = "mime_type";// 数据的MIME类型
+
+        /**
+         * The reference id to note that this data belongs to
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String NOTE_ID = "note_id";// 数据ID
+
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date";// 创建日期
+
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date";// 最后修改日期
+
+        /**
+         * Data's content
+         * <P> Type: TEXT </P>
+         */
+        public static final String CONTENT = "content";// 内容
+
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+        public static final String DATA1 = "data1";// 通用数据1
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+        public static final String DATA2 = "data2";// 通用数据2
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA3 = "data3";// 通用数据3
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA4 = "data4";// 通用数据4
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA5 = "data5";// 通用数据5
+    }
+
+    /*
+    * 定义了文本便签的数据结构
+    */
+    public static final class TextNote implements DataColumns {
+        /**
+         * Mode to indicate the text in check list mode or not
+         * <P> Type: Integer 1:check list mode 0: normal mode </P>
+         */
+        public static final String MODE = DATA1;// 模式
+
+        public static final int MODE_CHECK_LIST = 1;// 待办清单模式
+
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/text_note";// 内容类型
+
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/text_note";// 单个条目的内容类型
+
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/text_note");// 查询文本便签的URI
+    }
+
+    /*
+    * 定义电话便签的数据结构
+    */
+    public static final class CallNote implements DataColumns {
+        /**
+         * Call date for this record
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CALL_DATE = DATA1;// 通话日期
+
+        /**
+         * Phone number for this record
+         * <P> Type: TEXT </P>
+         */
+        public static final String PHONE_NUMBER = DATA3;// 电话号码
+
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/call_note";// 内容类型
+
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/call_note";// 单个条目的内容类型
+
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/call_note");// 查询电话便签的URI
+    }
+}
diff --git a/src/Notes-master/app/src/main/java/net/micode/notes/data/data/NotesDatabaseHelper.java b/src/Notes-master/app/src/main/java/net/micode/notes/data/data/NotesDatabaseHelper.java
new file mode 100644
index 0000000..373201a
--- /dev/null
+++ b/src/Notes-master/app/src/main/java/net/micode/notes/data/data/NotesDatabaseHelper.java
@@ -0,0 +1,506 @@
+/*
+ * 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;
+
+
+import android.content.ContentValues;//就是用于保存一些数据（string boolean byte double float int long short ...）信息，这些信息可以被数据库操作时使用。
+import android.content.Context;//加载和访问资源。（android中主要是这两个功能，但是这里具体不清楚）
+import android.database.sqlite.SQLiteDatabase;//主要提供了对应于添加、删除、更新、查询的操作方法： insert()、delete()、update()和query()。配合content.values
+import android.database.sqlite.SQLiteOpenHelper;//用来管理数据的创建和版本更新
+import android.util.Log;
+
+
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
+/*
+* 功能描述：数据库操作，用SQLOpenhelper,对一些note和文件进行数据库的操作
+*/
+
+public class NotesDatabaseHelper extends SQLiteOpenHelper {
+    private static final String DB_NAME = "note.db";// 数据库名
+
+    private static final int DB_VERSION = 4;// 版本号
+
+    public interface TABLE {
+        /*
+        * 接口，分成note和data,用于表示数据库中两种表格
+        * */
+        public static final String NOTE = "note";
+
+        public static final String DATA = "data";
+    }
+
+    private static final String TAG = "NotesDatabaseHelper";// 日志标签，用于在日志中标识数据库操作的相关信息
+
+    /*
+    * NotesDatabaseHelper 类的实例，用于单例模式的数据库操作，通过 getInstance() 方法获取 NotesDatabaseHelper 的唯一实例
+    * 单例模式是一种设计模式，在数据库操作中使用单例模式可以确保只有一个数据库连接，避免了重复创建和关闭数据库连接可能导致的性能问题
+    */
+    private static NotesDatabaseHelper mInstance;
+
+    /*
+    * 创建TABLE.NOTE表格，用于存储便签的相关信息
+    */
+    private static final String CREATE_NOTE_TABLE_SQL =
+        "CREATE TABLE " + TABLE.NOTE + "(" +
+            NoteColumns.ID + " INTEGER PRIMARY KEY," +// 便签ID
+            NoteColumns.PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +// 便签父级的ID
+            NoteColumns.ALERTED_DATE + " INTEGER NOT NULL DEFAULT 0," +// 便签的提醒日期
+            NoteColumns.BG_COLOR_ID + " INTEGER NOT NULL DEFAULT 0," + // 便签的背景颜色ID
+            NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," + // 便签的创建日期
+            NoteColumns.HAS_ATTACHMENT + " INTEGER NOT NULL DEFAULT 0," +// 便签是否有附件
+            NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +// 便签的最后修改日期
+            NoteColumns.NOTES_COUNT + " INTEGER NOT NULL DEFAULT 0," +// 文件夹中的便签数量
+            NoteColumns.SNIPPET + " TEXT NOT NULL DEFAULT ''," +// 文件夹名称或便签的文本内容
+            NoteColumns.TYPE + " INTEGER NOT NULL DEFAULT 0," +// 便签的类型
+            NoteColumns.WIDGET_ID + " INTEGER NOT NULL DEFAULT 0," +// 便签的Widget ID
+            NoteColumns.WIDGET_TYPE + " INTEGER NOT NULL DEFAULT -1," +// 便签的Widget类型
+            NoteColumns.SYNC_ID + " INTEGER NOT NULL DEFAULT 0," +// 便签的同步ID
+            NoteColumns.LOCAL_MODIFIED + " INTEGER NOT NULL DEFAULT 0," +// 便签的本地修改标记
+            NoteColumns.ORIGIN_PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +// 原始父级便签的ID
+            NoteColumns.GTASK_ID + " TEXT NOT NULL DEFAULT ''," +// 便签在Google任务中的ID
+            NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0" +// 便签的版本号
+        ")";
+
+    /*
+    * 创建TABLE.DATA表格，用于存储便签中的数据
+    */
+    private static final String CREATE_DATA_TABLE_SQL =
+        "CREATE TABLE " + TABLE.DATA + "(" +
+            DataColumns.ID + " INTEGER PRIMARY KEY," +// 数据ID
+            DataColumns.MIME_TYPE + " TEXT NOT NULL," +// 数据ID数据的MIME类型
+            DataColumns.NOTE_ID + " INTEGER NOT NULL DEFAULT 0," +// 数据所属的便签的ID
+            NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +// 数据的创建日期
+            NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +// 数据的最后修改日期
+            DataColumns.CONTENT + " TEXT NOT NULL DEFAULT ''," +// 数据的内容
+            DataColumns.DATA1 + " INTEGER," +// 数据的附加信息1
+            DataColumns.DATA2 + " INTEGER," +// 数据的附加信息2
+            DataColumns.DATA3 + " TEXT NOT NULL DEFAULT ''," +// 数据的附加信息3
+            DataColumns.DATA4 + " TEXT NOT NULL DEFAULT ''," +// 数据的附加信息4
+            DataColumns.DATA5 + " TEXT NOT NULL DEFAULT ''" +// 数据的附加信息5
+        ")";
+
+    /*
+     * 创建一个名为 note_id_index 的索引，在 TABLE.DATA 表格的 DataColumns.NOTE_ID 列上创建索引，以提高查询性能
+     */
+    private static final String CREATE_DATA_NOTE_ID_INDEX_SQL =
+        "CREATE INDEX IF NOT EXISTS note_id_index ON " +
+        TABLE.DATA + "(" + DataColumns.NOTE_ID + ");";
+
+    /**
+     * Increase folder's note count when move note to the folder
+     */
+
+    /*
+    * 在更新 TABLE.NOTE 表格的 NoteColumns.PARENT_ID 列时，增加相应文件夹的便签计数
+    * 通过更新 TABLE.NOTE 表格中的 NoteColumns.NOTES_COUNT 列，将其加1
+     */
+    private static final String NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
+        "CREATE TRIGGER increase_folder_count_on_update "+
+        " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
+        "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
+        " END";
+
+    /**
+     * Decrease folder's note count when move note from folder
+     */
+
+    /*
+    * 在更新 TABLE.NOTE 表格的 NoteColumns.PARENT_ID 列时，减少相应文件夹的便签计数
+    * 通过更新 TABLE.NOTE 表格中的 NoteColumns.NOTES_COUNT 列，将其减1
+    */
+    private static final String NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
+        "CREATE TRIGGER decrease_folder_count_on_update " +
+        " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
+        "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
+        "  AND " + NoteColumns.NOTES_COUNT + ">0" + ";" +
+        " END";
+
+    /**
+     * Increase folder's note count when insert new note to the folder
+     */
+
+    /*
+    * 在向 TABLE.NOTE 表格插入新便签时，增加相应文件夹的便签计数
+    * 通过更新 TABLE.NOTE 表格中的 NoteColumns.NOTES_COUNT 列，将其加1
+    */
+    private static final String NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER =
+        "CREATE TRIGGER increase_folder_count_on_insert " +
+        " AFTER INSERT ON " + TABLE.NOTE +
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
+        "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
+        " END";
+
+    /**
+     * Decrease folder's note count when delete note from the folder
+     */
+
+    /*
+    * 在从 TABLE.NOTE 表格删除便签时，减少相应文件夹的便签计数
+    * 通过更新 TABLE.NOTE 表格中的 NoteColumns.NOTES_COUNT 列，将其减1
+    */
+    private static final String NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER =
+        "CREATE TRIGGER decrease_folder_count_on_delete " +
+        " AFTER DELETE ON " + TABLE.NOTE +
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
+        "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
+        "  AND " + NoteColumns.NOTES_COUNT + ">0;" +
+        " END";
+
+    /**
+     * Update note's content when insert data with type {@link DataConstants#NOTE}
+     */
+
+    /*
+    * 在向 TABLE.DATA 表格插入类型为 DataConstants.NOTE 的数据时，更新对应便签的内容
+    * 通过更新 TABLE.NOTE 表格中的 NoteColumns.SNIPPET 列，将其设置为新插入数据的内容
+    */
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER =
+        "CREATE TRIGGER update_note_content_on_insert " +
+        " AFTER INSERT ON " + TABLE.DATA +
+        " WHEN new." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+        " BEGIN" +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
+        "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
+        " END";
+
+    /**
+     * Update note's content when data with {@link DataConstants#NOTE} type has changed
+     */
+
+    /*
+    * 在更新类型为 DataConstants.NOTE 的数据时，更新对应便签的内容
+    * 通过触发器在 TABLE.DATA 表格上创建，在数据被更新后将新的内容更新到对应的便签中
+    */
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER =
+        "CREATE TRIGGER update_note_content_on_update " +
+        " AFTER UPDATE ON " + TABLE.DATA +
+        " WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+        " BEGIN" +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
+        "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
+        " END";
+
+    /**
+     * Update note's content when data with {@link DataConstants#NOTE} type has deleted
+     */
+
+    /*
+     * 在删除类型为 DataConstants.NOTE 的数据时，更新对应便签的内容
+     * 通过触发器在 TABLE.DATA 表格上创建，在数据被删除后将对应的便签内容清空
+     */
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER =
+        "CREATE TRIGGER update_note_content_on_delete " +
+        " AFTER delete ON " + TABLE.DATA +
+        " WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+        " BEGIN" +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.SNIPPET + "=''" +
+        "  WHERE " + NoteColumns.ID + "=old." + DataColumns.NOTE_ID + ";" +
+        " END";
+
+    /**
+     * Delete datas belong to note which has been deleted
+     */
+
+    /*
+    * 在删除便签时，同时删除该便签相关的数据
+    * 通过触发器在 TABLE.NOTE 表格上创建，在便签被删除后将与该便签相关的数据一并删除
+    */
+    private static final String NOTE_DELETE_DATA_ON_DELETE_TRIGGER =
+        "CREATE TRIGGER delete_data_on_delete " +
+        " AFTER DELETE ON " + TABLE.NOTE +
+        " BEGIN" +
+        "  DELETE FROM " + TABLE.DATA +
+        "   WHERE " + DataColumns.NOTE_ID + "=old." + NoteColumns.ID + ";" +
+        " END";
+
+    /**
+     * Delete notes belong to folder which has been deleted
+     */
+
+    /*
+     * 在删除文件夹时，同时删除该文件夹下的所有便签
+     * 通过触发器在 TABLE.NOTE 表格上创建，在文件夹被删除后将该文件夹下的所有便签一并删除。
+     */
+    private static final String FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER =
+        "CREATE TRIGGER folder_delete_notes_on_delete " +
+        " AFTER DELETE ON " + TABLE.NOTE +
+        " BEGIN" +
+        "  DELETE FROM " + TABLE.NOTE +
+        "   WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
+        " END";
+
+    /**
+     * Move notes belong to folder which has been moved to trash folder
+     */
+
+    /*
+     * 在将文件夹移动到回收站时，同时将该文件夹下的所有便签一并移动到回收站
+     * 通过触发器在 TABLE.NOTE 表格上创建，在文件夹被移动到回收站后将该文件夹下的所有便签的父文件夹ID更新为回收站的ID
+     */
+    private static final String FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER =
+        "CREATE TRIGGER folder_move_notes_on_trash " +
+        " AFTER UPDATE ON " + TABLE.NOTE +
+        " WHEN new." + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER +
+        " BEGIN" +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER +
+        "  WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
+        " END";
+
+    /*
+    * 构造函数，传入数据库的名称和版本
+    */
+    public NotesDatabaseHelper(Context context) {
+        super(context, DB_NAME, null, DB_VERSION);
+    }
+
+    /*
+    * 用于创建存储标签属性的表格
+    */
+    public void createNoteTable(SQLiteDatabase db) {
+        db.execSQL(CREATE_NOTE_TABLE_SQL);
+        reCreateNoteTableTriggers(db);
+        createSystemFolder(db);
+        Log.d(TAG, "note table has been created");
+    }
+
+    /*
+    * 用于重新创建数据库中的触发器
+    */
+    private void reCreateNoteTableTriggers(SQLiteDatabase db) {
+        // 通过执行SQL语句DROP TRIGGER IF EXISTS来删除已存在的触发器，以确保不会重复创建
+        db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_update");
+        db.execSQL("DROP TRIGGER IF EXISTS decrease_folder_count_on_update");
+        db.execSQL("DROP TRIGGER IF EXISTS decrease_folder_count_on_delete");
+        db.execSQL("DROP TRIGGER IF EXISTS delete_data_on_delete");
+        db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_insert");
+        db.execSQL("DROP TRIGGER IF EXISTS folder_delete_notes_on_delete");
+        db.execSQL("DROP TRIGGER IF EXISTS folder_move_notes_on_trash");
+        // 创建新的触发器
+        db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER);// 增加文件夹计数的触发器
+        db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER);// 减少文件夹计数的触发器
+        db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER);// 删除文件夹计数的触发器
+        db.execSQL(NOTE_DELETE_DATA_ON_DELETE_TRIGGER);// 在删除时同时删除数据的触发器
+        db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER);// 增加文件夹计数的触发器
+        db.execSQL(FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER);// 在删除时同时删除文件夹中的笔记的触发器
+        db.execSQL(FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER);// 将笔记移动到垃圾箱的触发器
+    }
+
+    /*
+    *用于创建系统文件夹，插入四个不同类型的文件夹记录到 NoteColumns 表中
+    */
+    private void createSystemFolder(SQLiteDatabase db) {
+        ContentValues values = new ContentValues();
+
+        /**
+         * call record foler for call notes
+         */
+        /*
+         * 创建通话记录文件夹
+         */
+        values.put(NoteColumns.ID, Notes.ID_CALL_RECORD_FOLDER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+
+        /**
+         * root folder which is default folder
+         */
+        /*
+         * 根目录，即默认文件夹
+         */
+        values.clear();
+        values.put(NoteColumns.ID, Notes.ID_ROOT_FOLDER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+
+        /**
+         * temporary folder which is used for moving note
+         */
+        /*
+         * 临时目录，用于移动笔记
+         */
+        values.clear();
+        values.put(NoteColumns.ID, Notes.ID_TEMPARAY_FOLDER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+
+        /**
+         * create trash folder
+         */
+        /*
+         * 创建垃圾箱
+         */
+        values.clear();
+        values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+    }
+
+    /*
+     * 用于创建存储标签内容的表格
+     */
+    public void createDataTable(SQLiteDatabase db) {
+        db.execSQL(CREATE_DATA_TABLE_SQL);// 执行 CREATE_DATA_TABLE_SQL 的 SQL 语句来创建数据表
+        reCreateDataTableTriggers(db);// 调用 reCreateDataTableTriggers() 方法重新创建数据表中的触发器
+        db.execSQL(CREATE_DATA_NOTE_ID_INDEX_SQL);// 执行 CREATE_DATA_NOTE_ID_INDEX_SQL 的 SQL 语句来创建一个索引
+        Log.d(TAG, "data table has been created");
+    }
+
+    /*
+    * 用于重新创建数据表中的触发器
+    */
+    private void reCreateDataTableTriggers(SQLiteDatabase db) {
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_insert");
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_update");
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_delete");
+
+        db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER);
+        db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER);
+        db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER);
+    }
+
+    /*
+    * 用于获取单例的数据库帮助类对象
+    * 解决同一时刻只能有一个线程执行.
+    * 在写程序库代码时，有时有一个类需要被所的其它类使用
+    * 但又要求这个类只能被实例化一次，是个服务类，定义一次，其它类使用同一个这个类的实例
+    */
+    static synchronized NotesDatabaseHelper getInstance(Context context) {
+        if (mInstance == null) {
+            mInstance = new NotesDatabaseHelper(context);
+        }
+        return mInstance;
+    }
+
+    @Override
+    /*
+    * 在数据库第一次创建时被调用，用于创建所需的表格和触发器
+    */
+    public void onCreate(SQLiteDatabase db) {
+        createNoteTable(db);
+        createDataTable(db);
+    }
+
+    @Override
+    /*
+    * 根据旧版本和新版本之间的差异来执行相应的数据库升级操作
+    */
+    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+        boolean reCreateTriggers = false;
+        boolean skipV2 = false;// 是否进行V2升级
+        /*
+        * 如果旧版本为1，则调用upgradeToV2方法
+        */
+        if (oldVersion == 1) {
+            upgradeToV2(db);
+            skipV2 = true; // this upgrade including the upgrade from v2 to v3
+            oldVersion++;
+        }
+        /*
+        * 如果旧版本为2且未跳过V2升级，则调用upgradeToV3方法
+        */
+        if (oldVersion == 2 && !skipV2) {
+            upgradeToV3(db);
+            reCreateTriggers = true;
+            oldVersion++;
+        }
+        /*
+        * 如果旧版本为3，则调用upgradeToV4方法
+        */
+        if (oldVersion == 3) {
+            upgradeToV4(db);
+            oldVersion++;
+        }
+        /*
+        * 如果需要重新创建触发器，则调用reCreateNoteTableTriggers和reCreateDataTableTriggers方法重新创建触发器
+        */
+        if (reCreateTriggers) {
+            reCreateNoteTableTriggers(db);
+            reCreateDataTableTriggers(db);
+        }
+        /*
+        * 如果旧版本和新版本不匹配，则抛出异常
+        */
+        if (oldVersion != newVersion) {
+            throw new IllegalStateException("Upgrade notes database to version " + newVersion
+                    + "fails");
+        }
+    }
+
+    /*
+    * 更新到V2版本
+    * */
+    private void upgradeToV2(SQLiteDatabase db) {
+        /*
+        * 通过执行SQL语句DROP TABLE IF EXISTS来删除旧的NOTE和DATA表格
+        * */
+        db.execSQL("DROP TABLE IF EXISTS " + TABLE.NOTE);
+        db.execSQL("DROP TABLE IF EXISTS " + TABLE.DATA);
+        createNoteTable(db);// 调用createNoteTable和createDataTable方法来创建新的NOTE表格
+        createDataTable(db);// 调用createNoteTable和createDataTable方法来创建新的DATA表格
+    }
+
+    /*
+    * 更新到V3版本
+    * */
+    private void upgradeToV3(SQLiteDatabase db) {
+        /*
+        * 执行SQL语句DROP TRIGGER IF EXISTS来移除不再使用的触发器
+        * */
+        // drop unused triggers
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_insert");
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_delete");
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_update");
+        /*
+        * 执行ALTER TABLE语句向NOTE表格中添加一个新的列GTASK_ID，该列的类型是TEXT，并设置默认值为''
+        * */
+        // add a column for gtask id
+        db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.GTASK_ID
+                + " TEXT NOT NULL DEFAULT ''");
+        /*
+        * 通过ContentValues对象向NOTE表格中插入一条记录，该记录代表垃圾箱系统文件夹
+        * */
+        // add a trash system folder
+        ContentValues values = new ContentValues();
+        values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+    }
+
+    /*
+    * 更新到V4版本
+    * */
+    private void upgradeToV4(SQLiteDatabase db) {
+        db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.VERSION
+                + " INTEGER NOT NULL DEFAULT 0");// 通过执行ALTER TABLE语句向NOTE表格中添加一个新的列VERSION，该列的类型是INTEGER，并设置默认值为0
+    }
+}
diff --git a/src/Notes-master/app/src/main/java/net/micode/notes/data/data/NotesProvider.java b/src/Notes-master/app/src/main/java/net/micode/notes/data/data/NotesProvider.java
new file mode 100644
index 0000000..64ac3bd
--- /dev/null
+++ b/src/Notes-master/app/src/main/java/net/micode/notes/data/data/NotesProvider.java
@@ -0,0 +1,359 @@
+/*
+ * 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;
+
+
+import android.app.SearchManager;
+import android.content.ContentProvider;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.Intent;
+import android.content.UriMatcher;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+import android.net.Uri;
+import android.text.TextUtils;
+import android.util.Log;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.data.NotesDatabaseHelper.TABLE;
+
+/*
+* 功能描述：用于提供对便签数据的存储和获取功能，实现了创建、读取、更新、删除操作，以便其他组件可以通过 ContentResolver 访问和管理便签数据。
+* */
+public class NotesProvider extends ContentProvider {
+    private static final UriMatcher mMatcher;// UriMatcher用于匹配Uri
+
+    private NotesDatabaseHelper mHelper;// 数据库帮助类
+
+    private static final String TAG = "NotesProvider";// 标签
+
+    private static final int URI_NOTE            = 1;// Uri匹配码
+    private static final int URI_NOTE_ITEM       = 2;
+    private static final int URI_DATA            = 3;
+    private static final int URI_DATA_ITEM       = 4;
+
+    private static final int URI_SEARCH          = 5;
+    private static final int URI_SEARCH_SUGGEST  = 6;
+
+    static {
+        mMatcher = new UriMatcher(UriMatcher.NO_MATCH);// 创建UriMatcher时，调用UriMatcher(UriMatcher.NO_MATCH)表示不匹配任何路径的返回码
+        /*
+        * 把需要匹配Uri路径全部给注册上
+        * */
+        mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE);// 便签列表的路径
+        mMatcher.addURI(Notes.AUTHORITY, "note/#", URI_NOTE_ITEM);// 便签详情的路径，其中 "#" 表示数字，表示具体的便签 ID
+        mMatcher.addURI(Notes.AUTHORITY, "data", URI_DATA);// 数据列表的路径
+        mMatcher.addURI(Notes.AUTHORITY, "data/#", URI_DATA_ITEM);// 数据详情的路径，其中 "#" 表示数字，表示具体的数据 ID
+        mMatcher.addURI(Notes.AUTHORITY, "search", URI_SEARCH);// 搜索的路径
+        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY, URI_SEARCH_SUGGEST);// 搜索建议的路径
+        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY + "/*", URI_SEARCH_SUGGEST);// 带搜索关键字的搜索建议的路径
+    }
+
+    /**
+     * x'0A' represents the '\n' character in sqlite. For title and content in the search result,
+     * we will trim '\n' and white space in order to show more information.
+     */
+
+    /*
+    * 查询搜索结果的投影。该投影包含了搜索结果需要的各个字段，如便签的 ID、搜索文本等
+    * */
+    private static final String NOTES_SEARCH_PROJECTION = NoteColumns.ID + ","
+        + NoteColumns.ID + " AS " + SearchManager.SUGGEST_COLUMN_INTENT_EXTRA_DATA + ","
+        + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_1 + ","
+        + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_2 + ","
+        + R.drawable.search_result + " AS " + SearchManager.SUGGEST_COLUMN_ICON_1 + ","
+        + "'" + Intent.ACTION_VIEW + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_ACTION + ","
+        + "'" + Notes.TextNote.CONTENT_TYPE + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_DATA;
+
+    /*
+    * 查询语句，用于查询搜索结果
+    * */
+    private static String NOTES_SNIPPET_SEARCH_QUERY = "SELECT " + NOTES_SEARCH_PROJECTION
+        + " FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.SNIPPET + " LIKE ?"
+        + " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER
+        + " AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE;
+
+    @Override
+    /*
+    *在onCreate()中初始化Context，实例化mHelper
+    * */
+    public boolean onCreate() {
+        mHelper = NotesDatabaseHelper.getInstance(getContext());
+        return true;
+    }
+
+    @Override
+    /*
+    * 根据传入的Uri进行数据库查询操作
+    * */
+    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
+            String sortOrder) {
+        Cursor c = null;// 定义一个Cursor对象用于存放查询结果
+        SQLiteDatabase db = mHelper.getReadableDatabase();// 获取可读数据库实例
+        String id = null;// 用于存放ID值
+        /*
+        * 根据Uri使用Matcher匹配相应的操作，对于不同的匹配值，在数据库中查找相应的条目
+        * */
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null,
+                        sortOrder);// 查询便签列表
+                break;
+            case URI_NOTE_ITEM:
+                id = uri.getPathSegments().get(1);// 获取Uri中的ID值
+                c = db.query(TABLE.NOTE, projection, NoteColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs, null, null, sortOrder);// 查询特定ID的便签详情
+                break;
+            case URI_DATA:
+                c = db.query(TABLE.DATA, projection, selection, selectionArgs, null, null,
+                        sortOrder);// 查询数据列表
+                break;
+            case URI_DATA_ITEM:
+                id = uri.getPathSegments().get(1); // 获取Uri中的ID值
+                c = db.query(TABLE.DATA, projection, DataColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs, null, null, sortOrder);// 查询特定ID的数据详情
+                break;
+            case URI_SEARCH:
+            case URI_SEARCH_SUGGEST:
+                if (sortOrder != null || projection != null) {
+                    throw new IllegalArgumentException(
+                            "do not specify sortOrder, selection, selectionArgs, or projection" + "with this query");// 如果存在不合法的参数则抛出异常
+                }
+
+                String searchString = null;
+                if (mMatcher.match(uri) == URI_SEARCH_SUGGEST) {
+                    if (uri.getPathSegments().size() > 1) {
+                        searchString = uri.getPathSegments().get(1); // 获取搜索关键字
+                    }
+                } else {
+                    searchString = uri.getQueryParameter("pattern"); // 获取搜索关键字
+                }
+
+                if (TextUtils.isEmpty(searchString)) {
+                    return null;// 如果搜索关键字为空则直接返回null
+                }
+
+                try {
+                    searchString = String.format("%%%s%%", searchString);// 格式化搜索关键字
+                    c = db.rawQuery(NOTES_SNIPPET_SEARCH_QUERY,
+                            new String[] { searchString });// 执行搜索查询
+                } catch (IllegalStateException ex) {
+                    Log.e(TAG, "got exception: " + ex.toString());// 捕获异常
+                }
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);// 对于未知的Uri抛出异常
+        }
+        if (c != null) {
+            c.setNotificationUri(getContext().getContentResolver(), uri);// 设置查询结果的变更通知URI
+        }
+        return c;// 返回查询结果的Cursor对象
+    }
+
+    @Override
+    /*
+    * 功能描述：实现对数据库表单的增加记录操作
+    * 输入参数：参数 uri 表示插入的 URI，values 表示插入的值
+    * */
+    public Uri insert(Uri uri, ContentValues values) {
+        SQLiteDatabase db = mHelper.getWritableDatabase();// 获得可写的数据库
+        long dataId = 0, noteId = 0, insertedId = 0;// 定义三个id值变量
+        /*
+        * 根据Uri使用Matcher匹配相应的操作
+        * */
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                insertedId = noteId = db.insert(TABLE.NOTE, null, values);// 在便签表中插入新记录
+                break;
+            case URI_DATA:
+                if (values.containsKey(DataColumns.NOTE_ID)) {
+                    noteId = values.getAsLong(DataColumns.NOTE_ID);// 如果数据内容包含NOTE_ID字段，获取NOTE_ID值
+                } else {
+                    Log.d(TAG, "Wrong data format without note id:" + values.toString());// 如果不包含则输出日志信息
+                }
+                insertedId = dataId = db.insert(TABLE.DATA, null, values);// 在数据表中插入新记录
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);// 对于未知的Uri抛出异常
+        }
+        // Notify the note uri
+        if (noteId > 0) {// 如果是便签新增操作
+            getContext().getContentResolver().notifyChange(
+                    ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId), null);// 通过ContentResolver对象发送通知，更新便签的变更通知URI
+        }
+
+        // Notify the data uri
+        if (dataId > 0) {// 如果是数据新增操作
+            getContext().getContentResolver().notifyChange(
+                    ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId), null);// 通过ContentResolver对象发送通知，更新数据的变更通知URI
+        }
+
+        return ContentUris.withAppendedId(uri, insertedId);// 返回插入的uri的路径
+    }
+
+    @Override
+    /*
+    * 功能描述：实现对数据库表单的删除记录操作
+    * 输入参数：参数 uri 表示删除的 URI，selection 表示删除条件，selectionArgs 表示删除条件值
+    * */
+    public int delete(Uri uri, String selection, String[] selectionArgs) {
+        //Uri代表要操作的数据，Android上可用的每种资源 -包括 图像、视频片段、音频资源等都可以用Uri来表示
+        int count = 0;// 定义计数变量
+        String id = null;// 定义id字符串变量
+        SQLiteDatabase db = mHelper.getWritableDatabase();// 获取可写数据库实例
+        boolean deleteData = false;// 是否删除数据标志位
+        /*
+        * 根据Uri使用Matcher匹配相应的操作
+        * */
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                selection = "(" + selection + ") AND " + NoteColumns.ID + ">0 ";// 对于便签的删除操作，添加额外的条件限制
+                count = db.delete(TABLE.NOTE, selection, selectionArgs);// 在便签表中删除符合条件的记录
+                break;
+            case URI_NOTE_ITEM:
+                id = uri.getPathSegments().get(1);// 获取Uri中的ID参数
+                /**
+                 * ID that smaller than 0 is system folder which is not allowed to
+                 * trash
+                 */
+                long noteId = Long.valueOf(id);
+                if (noteId <= 0) {// 如果ID小于等于0，则不允许删除
+                    break;
+                }
+                count = db.delete(TABLE.NOTE,
+                        NoteColumns.ID + "=" + id + parseSelection(selection), selectionArgs);// 在便签表中删除指定ID的记录
+                break;
+            case URI_DATA:
+                count = db.delete(TABLE.DATA, selection, selectionArgs);// 在数据表中删除符合条件的记录
+                deleteData = true;// 设置删除数据标志位为true
+                break;
+            case URI_DATA_ITEM:
+                id = uri.getPathSegments().get(1);// 获取Uri中的ID参数
+                count = db.delete(TABLE.DATA,
+                        DataColumns.ID + "=" + id + parseSelection(selection), selectionArgs);// 在数据表中删除指定ID的记录
+                deleteData = true;// 设置删除数据标志位为true
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);// 对于未知的Uri抛出异常
+        }
+        if (count > 0) {// 如果删除记录数大于0
+            if (deleteData) {
+                getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);// 通过ContentResolver对象发送通知，更新便签变更通知URI
+            }
+            getContext().getContentResolver().notifyChange(uri, null);// 通过ContentResolver对象发送通知，更新变更通知URI
+        }
+        return count;// 返回删除的记录数
+    }
+
+    @Override
+    /*
+    * 功能描述：实现对数据库表单的更新操作
+    * 输入参数：参数 uri 表示更新的 URI，values 表示更新的值，selection 表示更新条件，selectionArgs 表示更新条件值
+    * */
+    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
+        int count = 0;// 定义计数变量
+        String id = null;// 定义id字符串变量
+        SQLiteDatabase db = mHelper.getWritableDatabase();// 获取可写数据库实例
+        boolean updateData = false;// 是否更新数据标志位
+        /*
+        * 根据Uri使用Matcher匹配相应的操作
+        * */
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                increaseNoteVersion(-1, selection, selectionArgs);// 增加便签版本号，针对便签的更新操作，添加额外的条件限制
+                count = db.update(TABLE.NOTE, values, selection, selectionArgs);// 在便签表中更新符合条件的记录
+                break;
+            case URI_NOTE_ITEM:
+                id = uri.getPathSegments().get(1);// 获取Uri中的ID参数
+                increaseNoteVersion(Long.valueOf(id), selection, selectionArgs);// 增加便签版本号，针对便签的更新操作，添加额外的条件限制
+                count = db.update(TABLE.NOTE, values, NoteColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs);// 在便签表中更新指定ID的记录
+                break;
+            case URI_DATA:
+                count = db.update(TABLE.DATA, values, selection, selectionArgs);// 在数据表中更新符合条件的记录
+                updateData = true;// 设置更新数据标志位为tru
+                break;
+            case URI_DATA_ITEM:
+                id = uri.getPathSegments().get(1);// 获取Uri中的ID参数
+                count = db.update(TABLE.DATA, values, DataColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs);// 在数据表中更新指定ID的记录
+                updateData = true;// 设置更新数据标志位为true
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);// 对于未知的Uri抛出异常
+        }
+
+        if (count > 0) {// 如果更新记录数大于0
+            if (updateData) {
+                getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);// 通过ContentResolver对象发送通知，更新便签变更通知URI
+            }
+            getContext().getContentResolver().notifyChange(uri, null);// 通过ContentResolver对象发送通知，更新变更通知URI
+        }
+        return count;// 返回更新的记录数
+    }
+
+    /*
+    * 解析查询条件selection，如果selection不为空，则在其前面加上" AND "，用于拼接SQL语句
+    * */
+    private String parseSelection(String selection) {
+        return (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : "");
+    }
+
+    /*
+    * 根据传入的id和selection参数确定要更新的记录，并将版本号加1
+    * */
+    private void increaseNoteVersion(long id, String selection, String[] selectionArgs) {
+        StringBuilder sql = new StringBuilder(120);// 创建一个StringBuilder对象，用于构建SQL语句
+        sql.append("UPDATE ");// 构建UPDATE语句，指定要更新的表名
+        sql.append(TABLE.NOTE);// 表名
+        sql.append(" SET ");// 指定要更新的字段和新的值
+        sql.append(NoteColumns.VERSION);// 字段名
+        sql.append("=" + NoteColumns.VERSION + "+1 ");// 将版本号加1
+
+        if (id > 0 || !TextUtils.isEmpty(selection)) {
+            sql.append(" WHERE ");// 根据传入的参数决定是否添加WHERE子句
+        }
+        if (id > 0) {
+            sql.append(NoteColumns.ID + "=" + String.valueOf(id)); // 如果传入的id大于0，则表示只更新指定id的记录
+        }
+        if (!TextUtils.isEmpty(selection)) {// 如果传入的selection不为空，则根据它来确定要更新的记录
+            String selectString = id > 0 ? parseSelection(selection) : selection;// 调用parseSelection方法将selection转换为SQL语句中的WHERE子句
+            for (String args : selectionArgs) {
+                selectString = selectString.replaceFirst("\\?", args);// 替换WHERE子句中的问号占位符为实际的参数值
+            }
+            sql.append(selectString);// 添加WHERE子句到SQL语句中
+        }
+
+        // execSQL()方法可以执行insert、delete、update和CREATE TABLE之类有更改行为的SQL语句
+        mHelper.getWritableDatabase().execSQL(sql.toString());// 添加WHERE子句到SQL语句中
+    }
+
+    @Override
+    /*
+    * 功能描述：用于根据 URI 返回相应的 MIME 类型
+    * 输入参数：参数 uri 表示查询或操作的 URI
+    * 函数中是环境自动生成的，也可自己改写
+    * */
+    public String getType(Uri uri) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+}
