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tsrxns/java/net/micode/notes/tool/BackupUtils.java

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/*
* 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.Context;//Android提供的一个上下文对象可以用于访问应用程序的资源和执行一些操作。
import android.database.Cursor;//一个用于查询数据库结果集的接口,可以用于获取查询结果中的各个数据项。
import android.os.Environment;//提供了访问系统环境的方法,例如获取外部存储路径。
import android.text.TextUtils;//个包含各种字符串处理方法的工具类,例如判断字符串是否为空。
import android.text.format.DateFormat;//提供了各种日期和时间格式化的方法。
import android.util.Log;//Android提供的日志工具类用于打印调试信息。
import net.micode.notes.R;//应用程序的资源类,用于引用应用程序中的各种资源,如布局文件、图标、字符串等。
import net.micode.notes.data.Notes;//一个自定义的Notes数据类用于访问和操作备忘录的数据。
import net.micode.notes.data.Notes.DataColumns;//Notes数据类中定义的备忘录数据列常量。
import net.micode.notes.data.Notes.DataConstants;//Notes数据类中定义的备忘录数据常量。
import net.micode.notes.data.Notes.NoteColumns;//Notes数据类中定义的备忘录笔记列常量。
//用于文件操作,如创建文件、写入内容等。
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintStream;
public class BackupUtils {
private static final String TAG = "BackupUtils";
// Singleton stuff
private static BackupUtils sInstance;
public static synchronized BackupUtils getInstance(Context context) {
if (sInstance == null) {
//如果当前的备份不存在,则重新声明一个
sInstance = new BackupUtils(context);
}
return sInstance;
}
/**
* Following states are signs to represents backup or restore
* status
*///以下状态是表示备份或恢复状态的标志。
// Currently, the sdcard is not mounted SD卡没有被装到手机里
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) {//函数初始化
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 = "";
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parentid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 将文件导出到text
String noteId = notesCursor.getString(NOTE_COLUMN_ID);
exportNoteToText(noteId, ps);
} 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) {//利用光标来扫面内容区别为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 判断是否为空字符
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)) {
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
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输出流输出到特定文件目的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());//外部的储存路径
sb.append(context.getString(filePathResId));//文件的储存路径
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 {
if (!filedir.exists()) {
filedir.mkdir();//如果文件不存在就新建文件
}
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;
}
}