管理数据的创建和版本更新 更新笔记内容 版本更新

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

@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+ //管理数据的创建和版本更新 更新笔记内容 版本更新
+
 package net.micode.notes.data;//表示一个Java包（Package） 表示这个类在data包中
 //net.micode.notes.data是包的名称，它通常按照反向域名的方式命名，以确保唯一性和可读性。在这个包中，net是顶级域名的一部分，micode可能是小米，notes.data则是具体的子包结构，用于存放与数据相关的类。
 import android.content.ContentValues;//表示导入了Android框架中的 ContentValues 类。这是Android提供的一个用于存储数据库表中的键值对数据的类。
@@ -43,7 +45,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
     private static final String TAG = "NotesDatabaseHelper";
 
     private static NotesDatabaseHelper mInstance;
-
+    
     private static final String CREATE_NOTE_TABLE_SQL =
         "CREATE TABLE " + TABLE.NOTE + "(" +
             NoteColumns.ID + " INTEGER PRIMARY KEY," +
@@ -86,6 +88,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
 
     /**
      * Increase folder's note count when move note to the folder
+     *当将笔记移动到文件夹时，增加文件夹中的笔记数量
      */
     private static final String NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
         "CREATE TRIGGER increase_folder_count_on_update "+
@@ -98,6 +101,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
 
     /**
      * Decrease folder's note count when move note from folder
+     *当从一个文件夹中移动笔记时，减少该文件夹中的笔记数量
      */
     private static final String NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
         "CREATE TRIGGER decrease_folder_count_on_update " +
@@ -111,6 +115,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
 
     /**
      * Increase folder's note count when insert new note to the folder
+     *当插入新笔记到文件夹时，增加文件夹中的笔记数量
      */
     private static final String NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER =
         "CREATE TRIGGER increase_folder_count_on_insert " +
@@ -123,6 +128,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
 
     /**
      * Decrease folder's note count when delete note from the folder
+     *当从文件夹删除文件时，减少文件夹中笔记的数量
      */
     private static final String NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER =
         "CREATE TRIGGER decrease_folder_count_on_delete " +
@@ -136,6 +142,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
 
     /**
      * Update note's content when insert data with type {@link DataConstants#NOTE}
+     *插入数据并且数据类型为 DataConstants#NOTE 时，要更新笔记的内容
+     *{@link DataConstants#NOTE}: 它指向名为 DataConstants 的类中的 NOTE 常量
      */
     private static final String DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER =
         "CREATE TRIGGER update_note_content_on_insert " +
@@ -149,6 +157,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
 
     /**
      * Update note's content when data with {@link DataConstants#NOTE} type has changed
+     *当数据类型为DataConstants#NOTE改变的时候，更新笔记内容
      */
     private static final String DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER =
         "CREATE TRIGGER update_note_content_on_update " +
@@ -162,6 +171,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
 
     /**
      * Update note's content when data with {@link DataConstants#NOTE} type has deleted
+     *当数据类型为DataConstants#NOTE删掉的时候，更新笔记内容
      */
     private static final String DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER =
         "CREATE TRIGGER update_note_content_on_delete " +
@@ -186,6 +196,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
 
     /**
      * Delete notes belong to folder which has been deleted
+     *删除属于已删除注释的数据
      */
     private static final String FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER =
         "CREATE TRIGGER folder_delete_notes_on_delete " +
@@ -197,6 +208,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
 
     /**
      * Move notes belong to folder which has been moved to trash folder
+     *移动笔记属于已移动到垃圾邮件文件夹的文件夹
      */
     private static final String FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER =
         "CREATE TRIGGER folder_move_notes_on_trash " +
@@ -220,6 +232,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
     }
 
     private void reCreateNoteTableTriggers(SQLiteDatabase db) {
+        // 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");
@@ -227,12 +240,13 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
         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");
-
+        // 创建笔记表触发器，用于在更新时增加和减少文件夹中的笔记计数
         db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER);
         db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER);
         db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER);
         db.execSQL(NOTE_DELETE_DATA_ON_DELETE_TRIGGER);
         db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER);
+        // 创建文件夹表触发器，用于在删除文件夹时删除相关的笔记或将笔记移动到垃圾箱
         db.execSQL(FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER);
         db.execSQL(FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER);
     }
@@ -242,6 +256,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
 
         /**
          * call record foler for call notes
+         *为通话记录创建文件夹
          */
         values.put(NoteColumns.ID, Notes.ID_CALL_RECORD_FOLDER);
         values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
@@ -249,6 +264,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
 
         /**
          * root folder which is default folder
+         *设置根文件夹为默认文件夹
          */
         values.clear();
         values.put(NoteColumns.ID, Notes.ID_ROOT_FOLDER);
@@ -257,6 +273,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
 
         /**
          * temporary folder which is used for moving note
+         *创建临时文件夹用于移动笔记
          */
         values.clear();
         values.put(NoteColumns.ID, Notes.ID_TEMPARAY_FOLDER);
@@ -265,6 +282,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
 
         /**
          * create trash folder
+         *创建垃圾箱文件夹
          */
         values.clear();
         values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
@@ -280,10 +298,11 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
     }
 
     private void reCreateDataTableTriggers(SQLiteDatabase db) {
+        // 在删除数据时，如果相关触发器已存在，则先删除它
         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");
-
+        // 重新创建触发器，以便在数据表中进行插入操作时自动更新笔记内容
         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);
@@ -306,29 +325,29 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
         boolean reCreateTriggers = false;
         boolean skipV2 = false;
-
+        // 如果旧版本为1，则执行从版本1升级到版本2的操作
         if (oldVersion == 1) {
             upgradeToV2(db);
-            skipV2 = true; // this upgrade including the upgrade from v2 to v3
+            skipV2 = true; // this upgrade including the upgrade from v2 to v3 此升级包括从v2到v3的升级
             oldVersion++;
         }
-
+        // 如果旧版本为2且不跳过v2，则执行从版本2升级到版本3的操作
         if (oldVersion == 2 && !skipV2) {
             upgradeToV3(db);
             reCreateTriggers = true;
             oldVersion++;
         }
-
+        // 如果旧版本为3，则执行从版本3升级到版本4的操作
         if (oldVersion == 3) {
             upgradeToV4(db);
             oldVersion++;
         }
-
+        // 如果需要重新创建触发器，则重新创建笔记表和数据表的触发器
         if (reCreateTriggers) {
             reCreateNoteTableTriggers(db);
             reCreateDataTableTriggers(db);
         }
-
+        // 如果旧版本号不等于新版本号，则抛出异常，表示升级失败
         if (oldVersion != newVersion) {
             throw new IllegalStateException("Upgrade notes database to version " + newVersion
                     + "fails");
@@ -343,14 +362,14 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {//NotesDatabaseHelper
     }
 
     private void upgradeToV3(SQLiteDatabase db) {
-        // drop unused triggers
+        // drop unused triggers删除已存在的触发器
         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");
-        // add a column for gtask id
+        // add a column for gtask id 为gtask id添加一列
         db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.GTASK_ID
                 + " TEXT NOT NULL DEFAULT ''");
-        // add a trash system folder
+        // add a trash system folder 添加垃圾系统文件夹
         ContentValues values = new ContentValues();
         values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
         values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);