diff --git a/java/net/micode/notes/data/NotesProvider.java b/java/net/micode/notes/data/NotesProvider.java index edb0a60..2621d39 100644 --- a/java/net/micode/notes/data/NotesProvider.java +++ b/java/net/micode/notes/data/NotesProvider.java @@ -16,7 +16,6 @@ package net.micode.notes.data; - import android.app.SearchManager; import android.content.ContentProvider; import android.content.ContentUris; @@ -34,24 +33,31 @@ import net.micode.notes.data.Notes.DataColumns; import net.micode.notes.data.Notes.NoteColumns; import net.micode.notes.data.NotesDatabaseHelper.TABLE; - +/** + * 该类是一个内容提供者，用于处理对便签数据库的增删改查操作，并支持搜索功能。 + * 它继承自ContentProvider，提供了对便签表和数据记录表的访问接口。 + */ public class NotesProvider extends ContentProvider { + // URI匹配器，用于匹配不同的URI请求 private static final UriMatcher mMatcher; - + // 数据库帮助类实例 private NotesDatabaseHelper mHelper; - + // 日志标签，方便调试和日志记录 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; + // 定义不同URI的匹配码 + 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; + private static final int URI_SEARCH = 5; + private static final int URI_SEARCH_SUGGEST = 6; static { + // 初始化URI匹配器 mMatcher = new UriMatcher(UriMatcher.NO_MATCH); + // 添加不同URI的匹配规则 mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE); mMatcher.addURI(Notes.AUTHORITY, "note/#", URI_NOTE_ITEM); mMatcher.addURI(Notes.AUTHORITY, "data", URI_DATA); @@ -62,57 +68,82 @@ 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. + * 便签搜索的投影，定义了搜索结果的列 + * x'0A'表示sqlite中的'\n'字符，用于去除搜索结果中的换行符和空格，以显示更多信息 */ 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; + + 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; + // 便签片段搜索的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; + + " FROM " + TABLE.NOTE + + " WHERE " + NoteColumns.SNIPPET + " LIKE ?" + + " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER + + " AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE; + /** + * 内容提供者创建时调用，初始化数据库帮助类 + * + * @return 创建成功返回true，否则返回false + */ @Override public boolean onCreate() { + // 获取数据库帮助类实例 mHelper = NotesDatabaseHelper.getInstance(getContext()); return true; } + /** + * 处理查询请求，根据不同的URI匹配码执行相应的查询操作 + * + * @param uri 请求的URI + * @param projection 查询的列 + * @param selection 查询条件 + * @param selectionArgs 查询条件的参数 + * @param sortOrder 排序规则 + * @return 查询结果的游标 + */ @Override public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, - String sortOrder) { + String sortOrder) { Cursor c = null; + // 获取可读数据库 SQLiteDatabase db = mHelper.getReadableDatabase(); String id = null; switch (mMatcher.match(uri)) { case URI_NOTE: + // 查询便签表 c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null, sortOrder); break; case URI_NOTE_ITEM: + // 获取便签ID id = uri.getPathSegments().get(1); + // 查询指定ID的便签 c = db.query(TABLE.NOTE, projection, NoteColumns.ID + "=" + id + parseSelection(selection), selectionArgs, null, null, sortOrder); break; case URI_DATA: + // 查询数据记录表 c = db.query(TABLE.DATA, projection, selection, selectionArgs, null, null, sortOrder); break; case URI_DATA_ITEM: + // 获取数据记录ID id = uri.getPathSegments().get(1); + // 查询指定ID的数据记录 c = db.query(TABLE.DATA, projection, DataColumns.ID + "=" + id + parseSelection(selection), selectionArgs, null, null, sortOrder); break; case URI_SEARCH: case URI_SEARCH_SUGGEST: if (sortOrder != null || projection != null) { + // 搜索查询不允许指定排序规则和投影列 throw new IllegalArgumentException( "do not specify sortOrder, selection, selectionArgs, or projection" + "with this query"); } @@ -120,59 +151,80 @@ public class NotesProvider extends ContentProvider { String searchString = null; if (mMatcher.match(uri) == URI_SEARCH_SUGGEST) { if (uri.getPathSegments().size() > 1) { + // 从URI路径中获取搜索字符串 searchString = uri.getPathSegments().get(1); } } else { + // 从URI查询参数中获取搜索字符串 searchString = uri.getQueryParameter("pattern"); } if (TextUtils.isEmpty(searchString)) { + // 搜索字符串为空，返回null return null; } try { + // 处理搜索字符串，添加通配符 searchString = String.format("%%%s%%", searchString); + // 执行搜索查询 c = db.rawQuery(NOTES_SNIPPET_SEARCH_QUERY, - new String[] { searchString }); + new String[]{searchString}); } catch (IllegalStateException ex) { + // 处理查询异常 Log.e(TAG, "got exception: " + ex.toString()); } break; default: + // 未知URI，抛出异常 throw new IllegalArgumentException("Unknown URI " + uri); } if (c != null) { + // 设置游标通知URI，当数据变化时通知观察者 c.setNotificationUri(getContext().getContentResolver(), uri); } return c; } + /** + * 处理插入请求，根据不同的URI匹配码将数据插入到相应的表中 + * + * @param uri 请求的URI + * @param values 要插入的数据 + * @return 插入数据的URI + */ @Override public Uri insert(Uri uri, ContentValues values) { + // 获取可写数据库 SQLiteDatabase db = mHelper.getWritableDatabase(); long dataId = 0, noteId = 0, insertedId = 0; switch (mMatcher.match(uri)) { case URI_NOTE: + // 插入便签数据 insertedId = noteId = db.insert(TABLE.NOTE, null, values); break; case URI_DATA: if (values.containsKey(DataColumns.NOTE_ID)) { + // 获取便签ID noteId = values.getAsLong(DataColumns.NOTE_ID); } else { + // 数据格式错误，记录日志 Log.d(TAG, "Wrong data format without note id:" + values.toString()); } + // 插入数据记录 insertedId = dataId = db.insert(TABLE.DATA, null, values); break; default: + // 未知URI，抛出异常 throw new IllegalArgumentException("Unknown URI " + uri); } - // Notify the note uri + // 通知便签URI数据变化 if (noteId > 0) { getContext().getContentResolver().notifyChange( ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId), null); } - // Notify the data uri + // 通知数据记录URI数据变化 if (dataId > 0) { getContext().getContentResolver().notifyChange( ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId), null); @@ -181,96 +233,148 @@ public class NotesProvider extends ContentProvider { return ContentUris.withAppendedId(uri, insertedId); } + /** + * 处理删除请求，根据不同的URI匹配码从相应的表中删除数据 + * + * @param uri 请求的URI + * @param selection 删除条件 + * @param selectionArgs 删除条件的参数 + * @return 删除的数据行数 + */ @Override public int delete(Uri uri, String selection, String[] selectionArgs) { int count = 0; String id = null; + // 获取可写数据库 SQLiteDatabase db = mHelper.getWritableDatabase(); boolean deleteData = false; switch (mMatcher.match(uri)) { case URI_NOTE: + // 处理删除便签的条件 selection = "(" + selection + ") AND " + NoteColumns.ID + ">0 "; + // 删除便签数据 count = db.delete(TABLE.NOTE, selection, selectionArgs); break; case URI_NOTE_ITEM: + // 获取便签ID id = uri.getPathSegments().get(1); /** - * ID that smaller than 0 is system folder which is not allowed to - * trash + * ID小于0的是系统文件夹，不允许删除 */ long noteId = Long.valueOf(id); if (noteId <= 0) { break; } + // 删除指定ID的便签 count = db.delete(TABLE.NOTE, NoteColumns.ID + "=" + id + parseSelection(selection), selectionArgs); break; case URI_DATA: + // 删除数据记录 count = db.delete(TABLE.DATA, selection, selectionArgs); deleteData = true; break; case URI_DATA_ITEM: + // 获取数据记录ID id = uri.getPathSegments().get(1); + // 删除指定ID的数据记录 count = db.delete(TABLE.DATA, DataColumns.ID + "=" + id + parseSelection(selection), selectionArgs); deleteData = true; break; default: + // 未知URI，抛出异常 throw new IllegalArgumentException("Unknown URI " + uri); } if (count > 0) { if (deleteData) { + // 通知便签URI数据变化 getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null); } + // 通知当前URI数据变化 getContext().getContentResolver().notifyChange(uri, null); } return count; } + /** + * 处理更新请求，根据不同的URI匹配码更新相应表中的数据，并增加便签版本号 + * + * @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 更新的数据行数 + */ @Override public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) { int count = 0; String id = null; + // 获取可写数据库 SQLiteDatabase db = mHelper.getWritableDatabase(); boolean updateData = false; switch (mMatcher.match(uri)) { case URI_NOTE: + // 增加便签版本号 increaseNoteVersion(-1, selection, selectionArgs); + // 更新便签数据 count = db.update(TABLE.NOTE, values, selection, selectionArgs); break; case URI_NOTE_ITEM: + // 获取便签ID id = uri.getPathSegments().get(1); + // 增加指定ID便签的版本号 increaseNoteVersion(Long.valueOf(id), selection, selectionArgs); + // 更新指定ID的便签 count = db.update(TABLE.NOTE, values, NoteColumns.ID + "=" + id + parseSelection(selection), selectionArgs); break; case URI_DATA: + // 更新数据记录 count = db.update(TABLE.DATA, values, selection, selectionArgs); updateData = true; break; case URI_DATA_ITEM: + // 获取数据记录ID id = uri.getPathSegments().get(1); + // 更新指定ID的数据记录 count = db.update(TABLE.DATA, values, DataColumns.ID + "=" + id + parseSelection(selection), selectionArgs); updateData = true; break; default: + // 未知URI，抛出异常 throw new IllegalArgumentException("Unknown URI " + uri); } if (count > 0) { if (updateData) { + // 通知便签URI数据变化 getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null); } + // 通知当前URI数据变化 getContext().getContentResolver().notifyChange(uri, null); } return count; } + /** + * 解析查询条件，添加额外的条件 + * + * @param selection 查询条件 + * @return 解析后的查询条件 + */ private String parseSelection(String selection) { return (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : ""); } + /** + * 增加便签的版本号，根据ID和查询条件更新便签的版本号 + * + * @param id 便签ID + * @param selection 查询条件 + * @param selectionArgs 查询条件的参数 + */ private void increaseNoteVersion(long id, String selection, String[] selectionArgs) { StringBuilder sql = new StringBuilder(120); sql.append("UPDATE "); @@ -293,13 +397,19 @@ public class NotesProvider extends ContentProvider { sql.append(selectString); } + // 执行更新版本号的SQL语句 mHelper.getWritableDatabase().execSQL(sql.toString()); } + /** + * 获取URI对应的MIME类型，目前未实现 + * + * @param uri 请求的URI + * @return MIME类型 + */ @Override public String getType(Uri uri) { // TODO Auto-generated method stub return null; } - -} +} \ No newline at end of file