note/scr/NotesProvider.java

/*
 * 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;


public class NotesProvider extends ContentProvider {
    // 定义一个静态的UriMatcher对象，用于匹配URI
    private static final UriMatcher mMatcher;

    // 创建一个NotesDatabaseHelper实例
    private NotesDatabaseHelper mHelper;

    // 定义一个常量TAG，用于日志记录
    private static final String TAG = "NotesProvider";

    // 定义一些常量URI，用于匹配不同的数据表或操作
    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;

    // 在静态代码块中初始化mMatcher，添加匹配规则
    static {
        mMatcher = new UriMatcher(UriMatcher.NO_MATCH);
        mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE);
        mMatcher.addURI(Notes.AUTHORITY, "note/#", URI_NOTE_ITEM);
        mMatcher.addURI(Notes.AUTHORITY, "data", URI_DATA);
        mMatcher.addURI(Notes.AUTHORITY, "data/#", URI_DATA_ITEM);
        mMatcher.addURI(Notes.AUTHORITY, "search", URI_SEARCH);
        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY, URI_SEARCH_SUGGEST);
        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY + "/*", URI_SEARCH_SUGGEST);
    }

    // 定义一个常量字符串，用于搜索结果的投影
    private static final String NOTES_SEARCH_PROJECTION = ... //省略具体实现

    // 定义一个常量字符串，用于搜索查询语句
    private static final String NOTES_SNIPPET_SEARCH_QUERY = ... //省略具体实现

    @Override
    public boolean onCreate() {
        // 创建NotesDatabaseHelper实例并返回true
        mHelper = NotesDatabaseHelper.getInstance(getContext());
        return true;
    }

    @Override
    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
            String sortOrder) {
        // 根据传入的URI进行匹配，执行相应的数据库查询操作
        Cursor c = null;
        SQLiteDatabase db = mHelper.getReadableDatabase();
        String id = null;
        switch (mMatcher.match(uri)) {
            // ...省略其他case的处理逻辑...
        }
        // 如果Cursor不为空，设置通知URI并返回Cursor
        if (c != null) {
            c.setNotificationUri(getContext().getContentResolver(), uri);
        }
        return c;
    }

    @Override
    public Uri insert(Uri uri, ContentValues values) {
        // 根据传入的URI进行匹配，执行相应的数据库插入操作
        SQLiteDatabase db = mHelper.getWritableDatabase();
        long dataId = 0, noteId = 0, insertedId = 0;
        switch (mMatcher.match(uri)) {
            // ...省略其他case的处理逻辑...
        }
        // 如果有对应的noteId或dataId，通知相应的URI变化
        // ...省略通知逻辑...
        // 返回新插入数据的URI
        return ContentUris.withAppendedId(uri, insertedId);
    }

    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
        // 根据传入的URI进行匹配，执行相应的数据库删除操作
        int count = 0;
        String id = null;
        SQLiteDatabase db = mHelper.getWritableDatabase();
        boolean deleteData = false;
        switch (mMatcher.match(uri)) {
            // ...省略其他case的处理逻辑...
        }
        // 返回删除的数据条数
        return count;
    }

    // ...省略其他方法的实现...
}