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添加注释

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zbq
abandon 3 months ago
parent 0a5f074a70
commit 50d1550c68
1 changed files with 86 additions and 28 deletions
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112
Notes-master/src/net/micode/notes/data/NotesProvider.java
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@ -2,21 +2,15 @@
* 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;
import android.app.SearchManager;
import android.content.ContentProvider;
import android.content.ContentUris;
@ -34,23 +28,28 @@ import net.micode.notes.data.Notes.DataColumns;
import net.micode.notes.data.Notes.NoteColumns;
import net.micode.notes.data.NotesDatabaseHelper.TABLE;
/**
* 笔记应用的内容提供者
* 实现了Android ContentProvider接口，提供标准化的数据访问API
* 支持笔记和附属数据的CRUD操作以及全文搜索功能
*/
public class NotesProvider extends ContentProvider {
// URI匹配器，用于解析不同的URI请求
private static final UriMatcher mMatcher;
private NotesDatabaseHelper mHelper;
private NotesDatabaseHelper mHelper; // 数据库辅助类实例
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匹配码常量
private static final int URI_NOTE = 1; // 笔记集合
private static final int URI_NOTE_ITEM = 2; // 单个笔记
private static final int URI_DATA = 3; // 附属数据集合
private static final int URI_DATA_ITEM = 4; // 单个附属数据
private static final int URI_SEARCH = 5; // 搜索请求
private static final int URI_SEARCH_SUGGEST = 6; // 搜索建议
static {
// 初始化URI匹配器
mMatcher = new UriMatcher(UriMatcher.NO_MATCH);
mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE);
mMatcher.addURI(Notes.AUTHORITY, "note/#", URI_NOTE_ITEM);
@ -62,8 +61,12 @@ 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.
* 笔记搜索投影定义
* 定义了搜索结果的字段映射关系，包括：
* - 笔记ID
* - 搜索建议文本（去除换行符）
* - 图标资源
* - 点击意图（查看笔记详情）
*/
private static final String NOTES_SEARCH_PROJECTION = NoteColumns.ID + ","
+ NoteColumns.ID + " AS " + SearchManager.SUGGEST_COLUMN_INTENT_EXTRA_DATA + ","
@ -73,18 +76,31 @@ public class NotesProvider extends ContentProvider {
+ "'" + Intent.ACTION_VIEW + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_ACTION + ","
+ "'" + Notes.TextNote.CONTENT_TYPE + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_DATA;
/**
* 笔记搜索查询SQL
* 在笔记摘要中搜索关键词，并排除回收站中的笔记
*/
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;
/**
* 内容提供者初始化
* 获取数据库辅助类实例
*/
@Override
public boolean onCreate() {
mHelper = NotesDatabaseHelper.getInstance(getContext());
return true;
}
/**
* 查询数据
* 根据不同的URI类型执行相应的数据库查询操作
* 支持笔记查询、附属数据查询和搜索功能
*/
@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
String sortOrder) {
@ -93,25 +109,30 @@ public class NotesProvider extends ContentProvider {
String id = null;
switch (mMatcher.match(uri)) {
case URI_NOTE:
// 查询所有笔记
c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null,
sortOrder);
break;
case URI_NOTE_ITEM:
// 查询单个笔记
id = uri.getPathSegments().get(1);
c = db.query(TABLE.NOTE, projection, NoteColumns.ID + "=" + id
+ parseSelection(selection), selectionArgs, null, null, sortOrder);
break;
case URI_DATA:
// 查询所有附属数据
c = db.query(TABLE.DATA, projection, selection, selectionArgs, null, null,
sortOrder);
break;
case URI_DATA_ITEM:
// 查询单个附属数据
id = uri.getPathSegments().get(1);
c = db.query(TABLE.DATA, projection, DataColumns.ID + "=" + id
+ parseSelection(selection), selectionArgs, null, null, sortOrder);
break;
case URI_SEARCH:
case URI_SEARCH_SUGGEST:
// 搜索功能实现
if (sortOrder != null || projection != null) {
throw new IllegalArgumentException(
"do not specify sortOrder, selection, selectionArgs, or projection" + "with this query");
@ -131,6 +152,7 @@ public class NotesProvider extends ContentProvider {
}
try {
// 构建模糊搜索条件并执行查询
searchString = String.format("%%%s%%", searchString);
c = db.rawQuery(NOTES_SNIPPET_SEARCH_QUERY,
new String[] { searchString });
@ -142,20 +164,28 @@ public class NotesProvider extends ContentProvider {
throw new IllegalArgumentException("Unknown URI " + uri);
}
if (c != null) {
// 设置通知URI，数据变化时通知观察者
c.setNotificationUri(getContext().getContentResolver(), uri);
}
return c;
}
/**
* 插入数据
* 根据不同的URI类型执行相应的插入操作
* 插入后通知数据变化
*/
@Override
public Uri insert(Uri uri, ContentValues values) {
SQLiteDatabase db = mHelper.getWritableDatabase();
long dataId = 0, noteId = 0, insertedId = 0;
switch (mMatcher.match(uri)) {
case URI_NOTE:
// 插入笔记
insertedId = noteId = db.insert(TABLE.NOTE, null, values);
break;
case URI_DATA:
// 插入附属数据
if (values.containsKey(DataColumns.NOTE_ID)) {
noteId = values.getAsLong(DataColumns.NOTE_ID);
} else {
@ -166,13 +196,12 @@ public class NotesProvider extends ContentProvider {
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
// Notify the note uri
// 通知笔记和数据的URI变化
if (noteId > 0) {
getContext().getContentResolver().notifyChange(
ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId), null);
}
// Notify the data uri
if (dataId > 0) {
getContext().getContentResolver().notifyChange(
ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId), null);
@ -181,6 +210,12 @@ public class NotesProvider extends ContentProvider {
return ContentUris.withAppendedId(uri, insertedId);
}
/**
* 删除数据
* 根据不同的URI类型执行相应的删除操作
* 不允许删除系统文件夹（ID <= 0）
* 删除后通知数据变化
*/
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
int count = 0;
@ -195,8 +230,7 @@ public class NotesProvider extends ContentProvider {
case URI_NOTE_ITEM:
id = uri.getPathSegments().get(1);
/**
* ID that smaller than 0 is system folder which is not allowed to
* trash
* ID <= 0 的是系统文件夹，不允许删除
*/
long noteId = Long.valueOf(id);
if (noteId <= 0) {
@ -219,6 +253,7 @@ public class NotesProvider extends ContentProvider {
throw new IllegalArgumentException("Unknown URI " + uri);
}
if (count > 0) {
// 通知数据变化
if (deleteData) {
getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
}
@ -227,6 +262,12 @@ public class NotesProvider extends ContentProvider {
return count;
}
/**
* 更新数据
* 根据不同的URI类型执行相应的更新操作
* 更新笔记时自动增加版本号
* 更新后通知数据变化
*/
@Override
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
int count = 0;
@ -235,20 +276,24 @@ public class NotesProvider extends ContentProvider {
boolean updateData = false;
switch (mMatcher.match(uri)) {
case URI_NOTE:
// 更新笔记集合，增加版本号
increaseNoteVersion(-1, selection, selectionArgs);
count = db.update(TABLE.NOTE, values, selection, selectionArgs);
break;
case URI_NOTE_ITEM:
// 更新单个笔记，增加版本号
id = uri.getPathSegments().get(1);
increaseNoteVersion(Long.valueOf(id), selection, selectionArgs);
count = db.update(TABLE.NOTE, values, NoteColumns.ID + "=" + id
+ parseSelection(selection), selectionArgs);
break;
case URI_DATA:
// 更新附属数据集合
count = db.update(TABLE.DATA, values, selection, selectionArgs);
updateData = true;
break;
case URI_DATA_ITEM:
// 更新单个附属数据
id = uri.getPathSegments().get(1);
count = db.update(TABLE.DATA, values, DataColumns.ID + "=" + id
+ parseSelection(selection), selectionArgs);
@ -259,6 +304,7 @@ public class NotesProvider extends ContentProvider {
}
if (count > 0) {
// 通知数据变化
if (updateData) {
getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
}
@ -267,10 +313,18 @@ public class NotesProvider extends ContentProvider {
return count;
}
/**
* 解析查询条件
* 将附加的查询条件添加到主条件中
*/
private String parseSelection(String selection) {
return (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : "");
}
/**
* 增加笔记版本号
* 用于记录数据变更，支持同步冲突检测
*/
private void increaseNoteVersion(long id, String selection, String[] selectionArgs) {
StringBuilder sql = new StringBuilder(120);
sql.append("UPDATE ");
@ -279,6 +333,7 @@ public class NotesProvider extends ContentProvider {
sql.append(NoteColumns.VERSION);
sql.append("=" + NoteColumns.VERSION + "+1 ");
// 构建更新条件
if (id > 0 || !TextUtils.isEmpty(selection)) {
sql.append(" WHERE ");
}
@ -296,10 +351,13 @@ public class NotesProvider extends ContentProvider {
mHelper.getWritableDatabase().execSQL(sql.toString());
}
/**
* 获取URI对应的MIME类型
* 目前未实现，返回null
*/
@Override
public String getType(Uri uri) {
// TODO Auto-generated method stub
return null;
}
}
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