/* * 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; public class BackupUtils { private static final String TAG = "BackupUtils"; // Singleton stuff private static BackupUtils sInstance; //类里面为什么可以定义自身类的对象？ public static synchronized BackupUtils getInstance(Context context) { //ynchronized 关键字，代表这个方法加锁,相当于不管哪一个线程（例如线程A） //运行到这个方法时,都要检查有没有其它线程B（或者C、 D等）正在用这个方法(或者该类的其他同步方法)，有的话要等正在使用synchronized方法的线程B（或者C 、D）运行完这个方法后再运行此线程A,没有的话,锁定调用者,然后直接运行。 //它包括两种用法：synchronized 方法和 synchronized 块。 if (sInstance == null) { //如果当前备份不存在，则新声明一个 sInstance = new BackupUtils(context); } return sInstance; } /** * Following states are signs to represents backup or restore * status */ // Currently, the sdcard is not mounted SD卡没有被装入手机 public static final int STATE_SD_CARD_UNMOUONTED = 0; // The backup file not exist 备份文件夹不存在 public static final int STATE_BACKUP_FILE_NOT_EXIST = 1; // The data is not well formated, may be changed by other programs 数据已被破坏，可能被修改 public static final int STATE_DATA_DESTROIED = 2; // Some run-time exception which causes restore or backup fails 超时异常 public static final int STATE_SYSTEM_ERROR = 3; // Backup or restore success 成功存储 public static final int STATE_SUCCESS = 4; private TextExport mTextExport; private BackupUtils(Context context) { //初始化函数 mTextExport = new TextExport(context); } private static boolean externalStorageAvailable() { //外部存储功能是否可用 return Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState()); } public int exportToText() { return mTextExport.exportToText(); } public String getExportedTextFileName() { return mTextExport.mFileName; } public String getExportedTextFileDir() { return mTextExport.mFileDirectory; } private static class TextExport { private static final String[] NOTE_PROJECTION = { NoteColumns.ID, NoteColumns.MODIFIED_DATE, NoteColumns.SNIPPET, NoteColumns.TYPE }; private static final int NOTE_COLUMN_ID = 0; private static final int NOTE_COLUMN_MODIFIED_DATE = 1; private static final int NOTE_COLUMN_SNIPPET = 2; private static final String[] DATA_PROJECTION = { DataColumns.CONTENT, DataColumns.MIME_TYPE, DataColumns.DATA1, DataColumns.DATA2, DataColumns.DATA3, DataColumns.DATA4, }; private static final int DATA_COLUMN_CONTENT = 0; private static final int DATA_COLUMN_MIME_TYPE = 1; private static final int DATA_COLUMN_CALL_DATE = 2; private static final int DATA_COLUMN_PHONE_NUMBER = 4; private final String [] TEXT_FORMAT; private static final int FORMAT_FOLDER_NAME = 0; private static final int FORMAT_NOTE_DATE = 1; private static final int FORMAT_NOTE_CONTENT = 2; private Context mContext; private String mFileName; private String mFileDirectory; public TextExport(Context context) { TEXT_FORMAT = context.getResources().getStringArray(R.array.format_for_exported_note); mContext = context; mFileName = ""; //为什么为空? mFileDirectory = ""; } private String getFormat(int id) { //获取文本的组成部分 return TEXT_FORMAT[id]; } /** * Export the folder identified by folder id to text */ private void exportFolderToText(String folderId, PrintStream ps) { // Query notes belong to this folder 通过查询parent id是文件夹id的note来选出制定ID文件夹下的Note Cursor notesCursor = mContext.getContentResolver().query(Notes.CONTENT_NOTE_URI, NOTE_PROJECTION, NoteColumns.PARENT_ID + "=?", new String[] { folderId }, null); if (notesCursor != null) { if (notesCursor.moveToFirst()) { do { // Print note's last modified date ps里面保存有这份note的日期 ps.println(String.format(getFormat(FORMAT_NOTE_DATE), DateFormat.format( mContext.getString(R.string.format_datetime_mdhm), notesCursor.getLong(NOTE_COLUMN_MODIFIED_DATE)))); // Query data belong to this note String noteId = notesCursor.getString(NOTE_COLUMN_ID); exportNoteToText(noteId, ps); //将文件导出到text } while (notesCursor.moveToNext()); } notesCursor.close(); } } /** * Export note identified by id to a print stream */ private void exportNoteToText(String noteId, PrintStream ps) { Cursor dataCursor = mContext.getContentResolver().query(Notes.CONTENT_DATA_URI, DATA_PROJECTION, DataColumns.NOTE_ID + "=?", new String[] { noteId }, null); if (dataCursor != null) { //利用光标来扫描内容，区别为callnote和note两种，靠ps.printline输出 if (dataCursor.moveToFirst()) { do { String mimeType = dataCursor.getString(DATA_COLUMN_MIME_TYPE); if (DataConstants.CALL_NOTE.equals(mimeType)) { // Print phone number String phoneNumber = dataCursor.getString(DATA_COLUMN_PHONE_NUMBER); long callDate = dataCursor.getLong(DATA_COLUMN_CALL_DATE); String location = dataCursor.getString(DATA_COLUMN_CONTENT); if (!TextUtils.isEmpty(phoneNumber)) { //判断是否为空字符 ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT), phoneNumber)); } // Print call date ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT), DateFormat .format(mContext.getString(R.string.format_datetime_mdhm), callDate))); // Print call attachment location if (!TextUtils.isEmpty(location)) { ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT), location)); } } else if (DataConstants.NOTE.equals(mimeType)) { String content = dataCursor.getString(DATA_COLUMN_CONTENT); if (!TextUtils.isEmpty(content)) { ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT), content)); } } } while (dataCursor.moveToNext()); } dataCursor.close(); } // print a line separator between note try { ps.write(new byte[] { Character.LINE_SEPARATOR, Character.LETTER_NUMBER }); } catch (IOException e) { Log.e(TAG, e.toString()); } } /** * Note will be exported as text which is user readable */ public int exportToText() { //总函数，调用上面的exportFolder和exportNote if (!externalStorageAvailable()) { Log.d(TAG, "Media was not mounted"); return STATE_SD_CARD_UNMOUONTED; } PrintStream ps = getExportToTextPrintStream(); if (ps == null) { Log.e(TAG, "get print stream error"); return STATE_SYSTEM_ERROR; } // First export folder and its notes 导出文件夹，就是导出里面包含的便签 Cursor folderCursor = mContext.getContentResolver().query( Notes.CONTENT_NOTE_URI, NOTE_PROJECTION, "(" + NoteColumns.TYPE + "=" + Notes.TYPE_FOLDER + " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER + ") OR " + NoteColumns.ID + "=" + Notes.ID_CALL_RECORD_FOLDER, null, null); if (folderCursor != null) { if (folderCursor.moveToFirst()) { do { // Print folder's name String folderName = ""; if(folderCursor.getLong(NOTE_COLUMN_ID) == Notes.ID_CALL_RECORD_FOLDER) { folderName = mContext.getString(R.string.call_record_folder_name); } else { folderName = folderCursor.getString(NOTE_COLUMN_SNIPPET); } if (!TextUtils.isEmpty(folderName)) { ps.println(String.format(getFormat(FORMAT_FOLDER_NAME), folderName)); } String folderId = folderCursor.getString(NOTE_COLUMN_ID); exportFolderToText(folderId, ps); } while (folderCursor.moveToNext()); } folderCursor.close(); } // Export notes in root's folder 将根目录里的便签导出（由于不属于任何文件夹，因此无法通过文件夹导出来实现这一部分便签的导出） Cursor noteCursor = mContext.getContentResolver().query( Notes.CONTENT_NOTE_URI, NOTE_PROJECTION, NoteColumns.TYPE + "=" + +Notes.TYPE_NOTE + " AND " + NoteColumns.PARENT_ID + "=0", null, null); if (noteCursor != null) { if (noteCursor.moveToFirst()) { do { ps.println(String.format(getFormat(FORMAT_NOTE_DATE), DateFormat.format( mContext.getString(R.string.format_datetime_mdhm), noteCursor.getLong(NOTE_COLUMN_MODIFIED_DATE)))); // Query data belong to this note String noteId = noteCursor.getString(NOTE_COLUMN_ID); exportNoteToText(noteId, ps); } while (noteCursor.moveToNext()); } noteCursor.close(); } ps.close(); return STATE_SUCCESS; } /** * Get a print stream pointed to the file {@generateExportedTextFile} */ private PrintStream getExportToTextPrintStream() { File file = generateFileMountedOnSDcard(mContext, R.string.file_path, R.string.file_name_txt_format); if (file == null) { Log.e(TAG, "create file to exported failed"); return null; } mFileName = file.getName(); mFileDirectory = mContext.getString(R.string.file_path); PrintStream ps = null; try { FileOutputStream fos = new FileOutputStream(file); ps = new PrintStream(fos); //将ps输出流输出到特定的文件，目的就是导出到文件，而不是直接输出 } catch (FileNotFoundException e) { e.printStackTrace(); return null; } catch (NullPointerException e) { e.printStackTrace(); return null; } return ps; } } /** * Generate the text file to store imported data */ private static File generateFileMountedOnSDcard(Context context, int filePathResId, int fileNameFormatResId) { StringBuilder sb = new StringBuilder(); sb.append(Environment.getExternalStorageDirectory()); //外部（SD卡）的存储路径 sb.append(context.getString(filePathResId)); //文件的存储路径 File filedir = new File(sb.toString()); //filedir应该就是用来存储路径信息 sb.append(context.getString( fileNameFormatResId, DateFormat.format(context.getString(R.string.format_date_ymd), System.currentTimeMillis()))); File file = new File(sb.toString()); try { //如果这些文件不存在，则新建 if (!filedir.exists()) { filedir.mkdir(); } if (!file.exists()) { file.createNewFile(); } return file; } catch (SecurityException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } // try catch 异常处理 return null; } }