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

@@ -22,26 +22,39 @@ import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteOpenHelper;
 import android.util.Log;
 
-import net.micode.notes.data.Notes.DataColumns;  //导入声明数据表中的通用列名
-import net.micode.notes.data.Notes.DataConstants;  // 导入声明数据常量
-import net.micode.notes.data.Notes.NoteColumns;  //导入声明数据表中的专用列名
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
 
 
+/**
+ * 笔记应用的数据库助手类，负责创建和管理SQLite数据库
+ * 包括表结构定义、触发器创建、系统文件夹初始化和数据库版本升级
+ */
 public class NotesDatabaseHelper extends SQLiteOpenHelper {
+    // 数据库名称
     private static final String DB_NAME = "note.db";
 
+    // 数据库版本号
     private static final int DB_VERSION = 4;
 
+    /**
+     * 数据库表名定义接口
+     */
     public interface TABLE {
+        // 笔记表名
         public static final String NOTE = "note";
-
+        // 数据内容表名
         public static final String DATA = "data";
     }
 
+    // 日志标签
     private static final String TAG = "NotesDatabaseHelper";
 
+    // 单例实例
     private static NotesDatabaseHelper mInstance;
 
+    // 创建笔记表的SQL语句
     private static final String CREATE_NOTE_TABLE_SQL =
         "CREATE TABLE " + TABLE.NOTE + "(" +
             NoteColumns.ID + " INTEGER PRIMARY KEY," +
@@ -63,6 +76,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
             NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0" +
         ")";
 
+    // 创建数据内容表的SQL语句
     private static final String CREATE_DATA_TABLE_SQL =
         "CREATE TABLE " + TABLE.DATA + "(" +
             DataColumns.ID + " INTEGER PRIMARY KEY," +
@@ -78,6 +92,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
             DataColumns.DATA5 + " TEXT NOT NULL DEFAULT ''" +
         ")";
 
+    // 为数据内容表的note_id字段创建索引的SQL语句
     private static final String CREATE_DATA_NOTE_ID_INDEX_SQL =
         "CREATE INDEX IF NOT EXISTS note_id_index ON " +
         TABLE.DATA + "(" + DataColumns.NOTE_ID + ");";
@@ -206,10 +221,18 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         "  WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
         " END";
 
+    /**
+     * 构造方法
+     * @param context 上下文对象
+     */
     public NotesDatabaseHelper(Context context) {
         super(context, DB_NAME, null, DB_VERSION);
     }
 
+    /**
+     * 创建笔记表
+     * @param db SQLite数据库对象
+     */
     public void createNoteTable(SQLiteDatabase db) {
         db.execSQL(CREATE_NOTE_TABLE_SQL);
         reCreateNoteTableTriggers(db);
@@ -217,6 +240,10 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         Log.d(TAG, "note table has been created");
     }
 
+    /**
+     * 重新创建笔记表的触发器
+     * @param db SQLite数据库对象
+     */
     private void reCreateNoteTableTriggers(SQLiteDatabase db) {
         db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_update");
         db.execSQL("DROP TRIGGER IF EXISTS decrease_folder_count_on_update");
@@ -235,6 +262,10 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         db.execSQL(FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER);
     }
 
+    /**
+     * 创建系统文件夹
+     * @param db SQLite数据库对象
+     */
     private void createSystemFolder(SQLiteDatabase db) {
         ContentValues values = new ContentValues();
 
@@ -270,6 +301,10 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         db.insert(TABLE.NOTE, null, values);
     }
 
+    /**
+     * 创建数据内容表
+     * @param db SQLite数据库对象
+     */
     public void createDataTable(SQLiteDatabase db) {
         db.execSQL(CREATE_DATA_TABLE_SQL);
         reCreateDataTableTriggers(db);
@@ -277,6 +312,10 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         Log.d(TAG, "data table has been created");
     }
 
+    /**
+     * 重新创建数据内容表的触发器
+     * @param db SQLite数据库对象
+     */
     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");
@@ -287,6 +326,11 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER);
     }
 
+    /**
+     * 获取单例实例
+     * @param context 上下文对象
+     * @return NotesDatabaseHelper实例
+     */
     static synchronized NotesDatabaseHelper getInstance(Context context) {
         if (mInstance == null) {
             mInstance = new NotesDatabaseHelper(context);
@@ -294,12 +338,22 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         return mInstance;
     }
 
+    /**
+     * 创建数据库时调用
+     * @param db SQLite数据库对象
+     */
     @Override
     public void onCreate(SQLiteDatabase db) {
         createNoteTable(db);
         createDataTable(db);
     }
 
+    /**
+     * 数据库版本升级时调用
+     * @param db SQLite数据库对象
+     * @param oldVersion 旧版本号
+     * @param newVersion 新版本号
+     */
     @Override
     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
         boolean reCreateTriggers = false;
@@ -333,6 +387,10 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         }
     }
 
+    /**
+     * 升级数据库到版本2
+     * @param db SQLite数据库对象
+     */
     private void upgradeToV2(SQLiteDatabase db) {
         db.execSQL("DROP TABLE IF EXISTS " + TABLE.NOTE);
         db.execSQL("DROP TABLE IF EXISTS " + TABLE.DATA);
@@ -340,6 +398,10 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         createDataTable(db);
     }
 
+    /**
+     * 升级数据库到版本3
+     * @param db SQLite数据库对象
+     */
     private void upgradeToV3(SQLiteDatabase db) {
         // drop unused triggers
         db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_insert");
@@ -355,6 +417,10 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         db.insert(TABLE.NOTE, null, values);
     }
 
+    /**
+     * 升级数据库到版本4
+     * @param db SQLite数据库对象
+     */
     private void upgradeToV4(SQLiteDatabase db) {
         db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.VERSION
                 + " INTEGER NOT NULL DEFAULT 0");

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

@@ -35,20 +35,27 @@ import net.micode.notes.data.Notes.NoteColumns;
 import net.micode.notes.data.NotesDatabaseHelper.TABLE;
 
 
+/**
+ * 笔记应用的ContentProvider，负责处理所有数据操作请求
+ * 包括笔记和数据内容的增删改查，以及搜索功能
+ */
 public class NotesProvider extends ContentProvider {
+    // Uri匹配器，用于解析不同的请求URI
     private static final UriMatcher mMatcher;
 
+    // 数据库助手实例
     private NotesDatabaseHelper mHelper;
 
+    // 日志标签
     private static final String TAG = "NotesProvider";
 
-    private static final int URI_NOTE            = 1;
-    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;
+    // Uri匹配规则常量
+    private static final int URI_NOTE            = 1;   // 所有笔记
+    private static final int URI_NOTE_ITEM       = 2;   // 单个笔记
+    private static final int URI_DATA            = 3;   // 所有数据内容
+    private static final int URI_DATA_ITEM       = 4;   // 单个数据内容
+    private static final int URI_SEARCH          = 5;   // 搜索
+    private static final int URI_SEARCH_SUGGEST  = 6;   // 搜索建议
 
     static {
         mMatcher = new UriMatcher(UriMatcher.NO_MATCH);
@@ -65,6 +72,7 @@ public class NotesProvider extends ContentProvider {
      * 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.
      */
+    // 搜索结果的投影列定义
     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 + ","
@@ -73,18 +81,33 @@ public class NotesProvider extends ContentProvider {
         + "'" + Intent.ACTION_VIEW + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_ACTION + ","
         + "'" + Notes.TextNote.CONTENT_TYPE + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_DATA;
 
+    // 搜索笔记内容的SQL查询语句
     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;
 
+    /**
+     * ContentProvider创建时调用，初始化数据库助手
+     * @return true表示创建成功
+     */
     @Override
     public boolean onCreate() {
         mHelper = NotesDatabaseHelper.getInstance(getContext());
         return true;
     }
 
+    /**
+     * 查询数据
+     * @param uri 请求的URI
+     * @param projection 返回的列
+     * @param selection 选择条件
+     * @param selectionArgs 选择条件的参数
+     * @param sortOrder 排序方式
+     * @return 查询结果的Cursor
+     * @throws IllegalArgumentException 当URI不合法时抛出
+     */
     @Override
     public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
             String sortOrder) {
@@ -147,6 +170,13 @@ public class NotesProvider extends ContentProvider {
         return c;
     }
 
+    /**
+     * 插入数据
+     * @param uri 请求的URI
+     * @param values 要插入的数据
+     * @return 插入数据的URI
+     * @throws IllegalArgumentException 当URI不合法时抛出
+     */
     @Override
     public Uri insert(Uri uri, ContentValues values) {
         SQLiteDatabase db = mHelper.getWritableDatabase();
@@ -181,6 +211,14 @@ public class NotesProvider extends ContentProvider {
         return ContentUris.withAppendedId(uri, insertedId);
     }
 
+    /**
+     * 删除数据
+     * @param uri 请求的URI
+     * @param selection 删除条件
+     * @param selectionArgs 删除条件的参数
+     * @return 删除的行数
+     * @throws IllegalArgumentException 当URI不合法时抛出
+     */
     @Override
     public int delete(Uri uri, String selection, String[] selectionArgs) {
         int count = 0;
@@ -227,6 +265,15 @@ public class NotesProvider extends ContentProvider {
         return count;
     }
 
+    /**
+     * 更新数据
+     * @param uri 请求的URI
+     * @param values 要更新的数据
+     * @param selection 更新条件
+     * @param selectionArgs 更新条件的参数
+     * @return 更新的行数
+     * @throws IllegalArgumentException 当URI不合法时抛出
+     */
     @Override
     public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
         int count = 0;
@@ -267,10 +314,21 @@ public class NotesProvider extends ContentProvider {
         return count;
     }
 
+    /**
+     * 解析选择条件，添加到已有的条件中
+     * @param selection 要解析的选择条件
+     * @return 解析后的选择条件
+     */
     private String parseSelection(String selection) {
         return (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : "");
     }
 
+    /**
+     * 增加笔记版本号
+     * @param id 笔记ID，-1表示所有笔记
+     * @param selection 选择条件
+     * @param selectionArgs 选择条件的参数
+     */
     private void increaseNoteVersion(long id, String selection, String[] selectionArgs) {
         StringBuilder sql = new StringBuilder(120);
         sql.append("UPDATE ");
@@ -296,6 +354,11 @@ public class NotesProvider extends ContentProvider {
         mHelper.getWritableDatabase().execSQL(sql.toString());
     }
 
+    /**
+     * 获取URI对应的MIME类型
+     * @param uri 请求的URI
+     * @return MIME类型，当前未实现
+     */
     @Override
     public String getType(Uri uri) {
         // TODO Auto-generated method stub