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GPL_Project/other/06_210340049葛朋林_代码标注/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;
import android.database.Cursor;
import android.os.Environment;
import android.text.TextUtils;
import android.text.format.DateFormat;
import android.util.Log;
import net.micode.notes.R;
import net.micode.notes.data.Notes;
import net.micode.notes.data.Notes.DataColumns;
import net.micode.notes.data.Notes.DataConstants;
import net.micode.notes.data.Notes.NoteColumns;
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";
// 定义了一个 TAG 常量用于日志输出。
// Singleton stuff
private static BackupUtils sInstance;
// 然后,定义了一个静态的 sInstance 变量,表示类的唯一实例,
// 在 getInstance() 方法中进行初始化。getInstance() 方法接收一个 Context 对象,
// 并通过判断 sInstance 是否为空来决定是否需要创建一个新的 BackupUtils 实例。
public static synchronized BackupUtils getInstance(Context context) {
if (sInstance == null) {
sInstance = new BackupUtils(context);
}
return sInstance;
}
/**
* Following states are signs to represents backup or restore
* status
*/
// Currently, the sdcard is not mounted
public static final int STATE_SD_CARD_UNMOUONTED = 0;
// The backup file not exist
public static final int STATE_BACKUP_FILE_NOT_EXIST = 1;
// The data is not well formated, may be changed by other programs
public static final int STATE_DATA_DESTROIED = 2;
// Some run-time exception which causes restore or backup fails
public static final int STATE_SYSTEM_ERROR = 3;
// Backup or restore success
public static final int STATE_SUCCESS = 4;
private TextExport mTextExport;
//TextExport 对象用于导出文本格式的数据
private BackupUtils(Context context) {
mTextExport = new TextExport(context);
}
private static boolean externalStorageAvailable() {
return Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState());
}
//用于检查 SD 卡是否可用,如果当前 SD 卡挂载,则返回 true否则返回 false。
public int exportToText() {
return mTextExport.exportToText();
}
//返回输出文本的文件名
public String getExportedTextFileName() {
return mTextExport.mFileName;
}
//返回输出文本文件的路径
public String getExportedTextFileDir() {
return mTextExport.mFileDirectory;
}
private static class TextExport {
//定义了一个数组储存便签的信息
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;
//从context类实例中获取信息给对应的属性赋初始值
public TextExport(Context context) {
TEXT_FORMAT = context.getResources().getStringArray(R.array.format_for_exported_note);
mContext = context;
mFileName = "";
mFileDirectory = "";
}
//获取文本组成部分
//通过ID返回文件的格式信息
private String getFormat(int id) {
return TEXT_FORMAT[id];
}
/**
* Export the folder identified by folder id to text
*/
//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,通过文件夹ID将目录导出后成文件,输出文件夹至文本
private void exportFolderToText(String folderId, PrintStream ps) {
// Query notes belong to this folder
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.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);
} while (notesCursor.moveToNext());
}
notesCursor.close();
}
}
/**
* Export note identified by id to a print stream
*/
//将便签的内容以文本的形式显示在屏幕上。比如电话号码、打电话的日期等。
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) {
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)) {
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
*/
//以TEXT形式输出到外部设备
public int exportToText() {
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
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
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}
*/
//获取指向文件的打印流
//将要输出的内容整合到一个输出里并返回该输出流
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);
} catch (FileNotFoundException e) {
e.printStackTrace();
return null;
} catch (NullPointerException e) {
e.printStackTrace();
return null;
}
return ps;
}
}
/**
* Generate the text file to store imported data
*/
//产生用于存储输入信息的文件,使文本文件存储重要数据
private static File generateFileMountedOnSDcard(Context context, int filePathResId, int fileNameFormatResId) {
StringBuilder sb = new StringBuilder();
sb.append(Environment.getExternalStorageDirectory());
sb.append(context.getString(filePathResId));
File filedir = new File(sb.toString());
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();
}
if (!file.exists()) {
file.createNewFile();
}
return file;
} catch (SecurityException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}