Notes/src/tool/DataUtils.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.tool;

import android.content.ContentProviderOperation;
import android.content.ContentProviderResult;
import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.OperationApplicationException;
import android.database.Cursor;
import android.os.RemoteException;
import android.util.Log;

import net.micode.notes.data.Notes;
import net.micode.notes.data.Notes.CallNote;
import net.micode.notes.data.Notes.NoteColumns;
import net.micode.notes.ui.NotesListAdapter.AppWidgetAttribute;

import java.util.ArrayList;
import java.util.HashSet;


public class DataUtils {
    public static final String TAG = "DataUtils";
    //批量操作删除便签，发生错误就返回flase，删除成功就返回true
    public static boolean batchDeleteNotes(ContentResolver resolver, HashSet<Long> ids) {
        if (ids == null) {
            Log.d(TAG, "the ids is null");
            return true;
        }
        if (ids.size() == 0) {
            Log.d(TAG, "no id is in the hashset");
            return true;
        }
         // 构建删除操作：拼接标签ID到标签ContentUR
        ArrayList<ContentProviderOperation> operationList = new ArrayList<ContentProviderOperation>();
        for (long id : ids) {
            if(id == Notes.ID_ROOT_FOLDER) {
                Log.e(TAG, "Don't delete system folder root");
                continue;
            }

            ContentProviderOperation.Builder builder = ContentProviderOperation
                    .newDelete(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id));
                    //创建一个 ContentProviderOperation.Builder，删除指定id的标签   只查询 ID 为 id 的那一条记录
            operationList.add(builder.build());
        }
        try {
            ContentProviderResult[] results = resolver.applyBatch(Notes.AUTHORITY, operationList);
            if (results == null || results.length == 0 || results[0] == null) {////上面的一条执行数据库操作删除并返回结果数组
                Log.d(TAG, "delete notes failed, ids:" + ids.toString());
                return false;
            }
            return true;
        } catch (RemoteException e) {  //记录错误信息
            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
        } catch (OperationApplicationException e) {
            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
        }
        return false;
    }
    //便签转进新文件夹
    public static void moveNoteToFoler(ContentResolver resolver, long id, long srcFolderId, long desFolderId) {
        ContentValues values = new ContentValues();
        values.put(NoteColumns.PARENT_ID, desFolderId);
        values.put(NoteColumns.ORIGIN_PARENT_ID, srcFolderId);
        values.put(NoteColumns.LOCAL_MODIFIED, 1);
        resolver.update(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id), values, null, null);
    }
    //批量操作便签转进新文件夹
    public static boolean batchMoveToFolder(ContentResolver resolver, HashSet<Long> ids,
            long folderId) {
        if (ids == null) {
            Log.d(TAG, "the ids is null");
            return true;
        }

        ArrayList<ContentProviderOperation> operationList = new ArrayList<ContentProviderOperation>();
        for (long id : ids) {
            ContentProviderOperation.Builder builder = ContentProviderOperation
                    .newUpdate(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id)); //创建更新,
            builder.withValue(NoteColumns.PARENT_ID, folderId);
            builder.withValue(NoteColumns.LOCAL_MODIFIED, 1);
            operationList.add(builder.build());
        }

        try {
            ContentProviderResult[] results = resolver.applyBatch(Notes.AUTHORITY, operationList);
            if (results == null || results.length == 0 || results[0] == null) {
                Log.d(TAG, "delete notes failed, ids:" + ids.toString());
                return false;
            }
            return true;
        } catch (RemoteException e) {
            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
        } catch (OperationApplicationException e) {
            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
        }
        return false;
    }
    /**
     * Get the all folder count except system folders {@link Notes#TYPE_SYSTEM}}
     */
    public static int getUserFolderCount(ContentResolver resolver) {      
        //查询设备中「类型为文件夹（TYPE_FOLDER）」且「父文件夹 ID 不等于回收站 ID（ID_TRASH_FOLER）」的文件夹总数。
'''
触发了一次跨进程的数据库查询操作
Cursor query(
    Uri uri,                // 要查询的数据 URI
    String[] projection,    // 要返回的列（字段），null 表示所有列
    String selection,       // WHERE 子句（不含 "WHERE" 关键字）
    String[] selectionArgs, // WHERE 子句中占位符 ? 的实际值
    String sortOrder        // 排序方式（如 "date DESC"）
);
'''
        Cursor cursor =resolver.query(Notes.CONTENT_NOTE_URI,
                new String[] { "COUNT(*)" },
                NoteColumns.TYPE + "=? AND " + NoteColumns.PARENT_ID + "<>?",
                new String[] { String.valueOf(Notes.TYPE_FOLDER), String.valueOf(Notes.ID_TRASH_FOLER)},
                null);

        int count = 0;
        if(cursor != null) {
            if(cursor.moveToFirst()) {
                try {
                    count = cursor.getInt(0);//从当前游标指向的行中，读取第 0 列（第一列）的整数类型数据
                } catch (IndexOutOfBoundsException e) {
                    Log.e(TAG, "get folder count failed:" + e.toString());
                } finally {
                    cursor.close();
                }
            }
        }
        return count;
    }
    //变迁是否可见（没进回收站）
    public static boolean visibleInNoteDatabase(ContentResolver resolver, long noteId, int type) {
        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId),
                null,
                NoteColumns.TYPE + "=? AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER, //笔记的 parent_id 不能等于回收站的 ID（即不在回收站中）
                new String [] {String.valueOf(type)},
                null);

        boolean exist = false;
        if (cursor != null) {
            if (cursor.getCount() > 0) {
                exist = true;
            }
            cursor.close();
        }
        return exist;
    }
    //便签还存在否
    public static boolean existInNoteDatabase(ContentResolver resolver, long noteId) {
        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId),
                null, null, null, null);

        boolean exist = false;
        if (cursor != null) {
            if (cursor.getCount() > 0) {
                exist = true;
            }
            cursor.close();
        }
        return exist;
    }
    //便签数据还存在否
    public static boolean existInDataDatabase(ContentResolver resolver, long dataId) {
        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId),
                null, null, null, null);

        boolean exist = false;
        if (cursor != null) {
            if (cursor.getCount() > 0) {
                exist = true;
            }
            cursor.close();
        }
        return exist;
    }
    //查看是否存在一个名字是XX的文件夹
    public static boolean checkVisibleFolderName(ContentResolver resolver, String name) {
        Cursor cursor = resolver.query(Notes.CONTENT_NOTE_URI, null,
                NoteColumns.TYPE + "=" + Notes.TYPE_FOLDER + //类型是文件夹
                " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER +//没进回收站
                " AND " + NoteColumns.SNIPPET + "=?", //存储在snippet的名字和下面的name一样
                new String[] { name }, null);
        boolean exist = false;
        if(cursor != null) {
            if(cursor.getCount() > 0) {
                exist = true;
            }
            cursor.close();
        }
        return exist;
    }
    //获得文件夹下的便签，并仅返回它们的 Widget ID 和 Widget 类型
    public static HashSet<AppWidgetAttribute> getFolderNoteWidget(ContentResolver resolver, long folderId) {
        Cursor c = resolver.query(Notes.CONTENT_NOTE_URI, //获得便签
                new String[] { NoteColumns.WIDGET_ID, NoteColumns.WIDGET_TYPE },
                NoteColumns.PARENT_ID + "=?",
                new String[] { String.valueOf(folderId) },
                null);

        HashSet<AppWidgetAttribute> set = null;
        if (c != null) {
            if (c.moveToFirst()) {
                set = new HashSet<AppWidgetAttribute>();
                do {
                    try {
                        AppWidgetAttribute widget = new AppWidgetAttribute();
                        widget.widgetId = c.getInt(0);
                        widget.widgetType = c.getInt(1);
                        set.add(widget);
                    } catch (IndexOutOfBoundsException e) {
                        Log.e(TAG, e.toString());
                    }
                } while (c.moveToNext());
            }
            c.close();
        }
        return set;
    }
    //获得电话号
    public static String getCallNumberByNoteId(ContentResolver resolver, long noteId) {
        Cursor cursor = resolver.query(Notes.CONTENT_DATA_URI,
                new String [] { CallNote.PHONE_NUMBER },
                CallNote.NOTE_ID + "=? AND " + CallNote.MIME_TYPE + "=?",
                new String [] { String.valueOf(noteId), CallNote.CONTENT_ITEM_TYPE },
                null);

        if (cursor != null && cursor.moveToFirst()) {
            try {
                return cursor.getString(0); //返回电话号
            } catch (IndexOutOfBoundsException e) {
                Log.e(TAG, "Get call number fails " + e.toString());
            } finally {
                cursor.close();
            }
        }
        return "";
    }
//通过电话号和日期查找便签
    public static long getNoteIdByPhoneNumberAndCallDate(ContentResolver resolver, String phoneNumber, long callDate) {
        Cursor cursor = resolver.query(Notes.CONTENT_DATA_URI,
                new String [] { CallNote.NOTE_ID },
                CallNote.CALL_DATE + "=? AND " + CallNote.MIME_TYPE + "=? AND PHONE_NUMBERS_EQUAL("
                + CallNote.PHONE_NUMBER + ",?)",
                new String [] { String.valueOf(callDate), CallNote.CONTENT_ITEM_TYPE, phoneNumber },
                null);

        if (cursor != null) {
            if (cursor.moveToFirst()) {
                try {
                    return cursor.getLong(0);
                } catch (IndexOutOfBoundsException e) {
                    Log.e(TAG, "Get call note id fails " + e.toString());
                }
            }
            cursor.close();
        }
        return 0;
    }
//通过id获得名字
    public static String getSnippetById(ContentResolver resolver, long noteId) {
        Cursor cursor = resolver.query(Notes.CONTENT_NOTE_URI,
                new String [] { NoteColumns.SNIPPET },
                NoteColumns.ID + "=?",
                new String [] { String.valueOf(noteId)},
                null);

        if (cursor != null) {
            String snippet = "";
            if (cursor.moveToFirst()) {
                snippet = cursor.getString(0);
            }
            cursor.close();
            return snippet;
        }
        throw new IllegalArgumentException("Note is not found with id: " + noteId);
    }
//从一段文本（snippet）中提取作为标题
    public static String getFormattedSnippet(String snippet) {
        if (snippet != null) {
            snippet = snippet.trim();//清空无用制表符
            int index = snippet.indexOf('\n');//index即录字符串中第一个换行符 \n 出现的位置
            if (index != -1) {
                snippet = snippet.substring(0, index);//只获取换行前的部分（核心）。
            }
        }
        return snippet;
    }
}