diff --git a/src/net/micode/notes/tool/BackupUtils.java b/src/net/micode/notes/tool/BackupUtils.java index 39f6ec4..85ca9c1 100644 --- a/src/net/micode/notes/tool/BackupUtils.java +++ b/src/net/micode/notes/tool/BackupUtils.java @@ -37,13 +37,13 @@ import java.io.PrintStream; public class BackupUtils { - private static final String TAG = "BackupUtils"; + private static final String TAG = "BackupUtils";// 定义了一个私有静态常量字符串TAG，用于在日志中标记该类 // Singleton stuff - private static BackupUtils sInstance; + private static BackupUtils sInstance;// 声明了一个私有静态BackupUtils对象sInstance，用于实现单例模式 - public static synchronized BackupUtils getInstance(Context context) { + public static synchronized BackupUtils getInstance(Context context) {//获取BackupUtils类的实例的静态方法 if (sInstance == null) { - sInstance = new BackupUtils(context); + sInstance = new BackupUtils(context);//在第一次调用时，会创建一个新的BackupUtils对象，并将其赋值给静态变量sInstance } return sInstance; } @@ -53,53 +53,53 @@ public class BackupUtils { * status */ // Currently, the sdcard is not mounted - public static final int STATE_SD_CARD_UNMOUONTED = 0; + public static final int STATE_SD_CARD_UNMOUONTED = 0;//表示sd卡未挂载的状态。 // The backup file not exist - public static final int STATE_BACKUP_FILE_NOT_EXIST = 1; + public static final int STATE_BACKUP_FILE_NOT_EXIST = 1;//表示备份文件不存在的状态 // The data is not well formated, may be changed by other programs - public static final int STATE_DATA_DESTROIED = 2; + public static final int STATE_DATA_DESTROIED = 2;//表示数据格式错误，可能被其他程序修改的状态 // Some run-time exception which causes restore or backup fails - public static final int STATE_SYSTEM_ERROR = 3; + public static final int STATE_SYSTEM_ERROR = 3;//表示备份或还原过程中发生运行时异常的状态 // Backup or restore success - public static final int STATE_SUCCESS = 4; + public static final int STATE_SUCCESS = 4;//表示备份或还原成功的状态 private TextExport mTextExport; - private BackupUtils(Context context) { + private BackupUtils(Context context) {//用于初始化BackupUtils对象。在构造函数内部，创建了一个TextExport对象mTextExport。 mTextExport = new TextExport(context); } - private static boolean externalStorageAvailable() { + private static boolean externalStorageAvailable() {//检查外部存储是否可用 return Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState()); } - public int exportToText() { + public int exportToText() {//执行导出到文本的操作 return mTextExport.exportToText(); } - public String getExportedTextFileName() { + public String getExportedTextFileName() {//返回导出的文本文件名 return mTextExport.mFileName; } - public String getExportedTextFileDir() { + public String getExportedTextFileDir() {//导出的文本文件所在目录 return mTextExport.mFileDirectory; } - private static class TextExport { - private static final String[] NOTE_PROJECTION = { + private static class TextExport {//处理文本导出的具体实现 + private static final String[] NOTE_PROJECTION = {//查询备份数据的列名 NoteColumns.ID, NoteColumns.MODIFIED_DATE, NoteColumns.SNIPPET, NoteColumns.TYPE }; - private static final int NOTE_COLUMN_ID = 0; + private static final int NOTE_COLUMN_ID = 0;//笔记的ID列索引 - private static final int NOTE_COLUMN_MODIFIED_DATE = 1; + private static final int NOTE_COLUMN_MODIFIED_DATE = 1;//修改日期列索引 - private static final int NOTE_COLUMN_SNIPPET = 2; + private static final int NOTE_COLUMN_SNIPPET = 2;//摘要列索引 - private static final String[] DATA_PROJECTION = { + private static final String[] DATA_PROJECTION = {//查询的数据列 DataColumns.CONTENT, DataColumns.MIME_TYPE, DataColumns.DATA1, @@ -116,14 +116,14 @@ public class BackupUtils { 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 final String [] TEXT_FORMAT;//存储了用于格式化导出文本的模板字符串 + private static final int FORMAT_FOLDER_NAME = 0;//文件夹名称的格式索引 + private static final int FORMAT_NOTE_DATE = 1;//笔记日期的格式索引 + private static final int FORMAT_NOTE_CONTENT = 2;//笔记内容的格式索引 - private Context mContext; - private String mFileName; - private String mFileDirectory; + private Context mContext;//上下文对象 + private String mFileName;//文件名 + private String mFileDirectory;//文件所在的目录 public TextExport(Context context) { TEXT_FORMAT = context.getResources().getStringArray(R.array.format_for_exported_note); @@ -139,7 +139,7 @@ public class BackupUtils { /** * Export the folder identified by folder id to text */ - private void exportFolderToText(String folderId, PrintStream ps) { + private void exportFolderToText(String folderId, PrintStream ps) {//将该文件夹中的笔记导出为文本 // Query notes belong to this folder Cursor notesCursor = mContext.getContentResolver().query(Notes.CONTENT_NOTE_URI, NOTE_PROJECTION, NoteColumns.PARENT_ID + "=?", new String[] { @@ -148,12 +148,13 @@ public class BackupUtils { if (notesCursor != null) { if (notesCursor.moveToFirst()) { - do { + do {// 打印笔记的最后修改日期 // 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 + // 查询属于该笔记的数据 String noteId = notesCursor.getString(NOTE_COLUMN_ID); exportNoteToText(noteId, ps); } while (notesCursor.moveToNext()); @@ -171,17 +172,18 @@ public class BackupUtils { noteId }, null); - if (dataCursor != null) { + if (dataCursor != null) {//是否有符合条件的数据行 if (dataCursor.moveToFirst()) { + // 遍历游标以检索每个数据行的MIME类型 do { String mimeType = dataCursor.getString(DATA_COLUMN_MIME_TYPE); - if (DataConstants.CALL_NOTE.equals(mimeType)) { + if (DataConstants.CALL_NOTE.equals(mimeType)) {// 将电话号码、通话日期和位置信息打印到输出流中 // 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)) { + if (!TextUtils.isEmpty(phoneNumber)) {//判断是否为空字符 ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT), phoneNumber)); } @@ -218,43 +220,45 @@ public class BackupUtils { /** * Note will be exported as text which is user readable */ - public int exportToText() { - if (!externalStorageAvailable()) { - Log.d(TAG, "Media was not mounted"); - return STATE_SD_CARD_UNMOUONTED; + public int exportToText() { //总函数，调用上面的exportFolder和exportNote + if (!externalStorageAvailable()) {// 检查外部存储是否可用（即 SD 卡是否已挂载） + Log.d(TAG, "Media was not mounted");// 如果外部存储不可用，则在日志中记录错误消息 + return STATE_SD_CARD_UNMOUONTED;// 返回常量表示 SD 卡未挂载 } - PrintStream ps = getExportToTextPrintStream(); - if (ps == null) { + PrintStream ps = getExportToTextPrintStream();// 获取一个打印流来写入导出的笔记 + if (ps == null) {// 如果无法获取打印流，则记录错误消息并返回常量表示系统错误 Log.e(TAG, "get print stream error"); return STATE_SYSTEM_ERROR; } + // 首先导出文件夹及其下的笔记 // First export folder and its notes Cursor folderCursor = mContext.getContentResolver().query( - Notes.CONTENT_NOTE_URI, + Notes.CONTENT_NOTE_URI,// 查询内容 URI 表示要访问的数据库表 NOTE_PROJECTION, - "(" + NoteColumns.TYPE + "=" + Notes.TYPE_FOLDER + " AND " + "(" + NoteColumns.TYPE + "=" + Notes.TYPE_FOLDER + " AND "// 查询条件 + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER + ") OR " - + NoteColumns.ID + "=" + Notes.ID_CALL_RECORD_FOLDER, null, null); + + NoteColumns.ID + "=" + Notes.ID_CALL_RECORD_FOLDER, null, null);//查询中用的可选参数 - if (folderCursor != null) { + if (folderCursor != null) {// 如果能够查询到文件夹 if (folderCursor.moveToFirst()) { do { // Print folder's name + // 打印文件夹的名称 String folderName = ""; - if(folderCursor.getLong(NOTE_COLUMN_ID) == Notes.ID_CALL_RECORD_FOLDER) { + if(folderCursor.getLong(NOTE_COLUMN_ID) == Notes.ID_CALL_RECORD_FOLDER) {// // 如果当前文件夹是来电录音文件夹 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)); + if (!TextUtils.isEmpty(folderName)) {// 如果文件夹名称不为空 + ps.println(String.format(getFormat(FORMAT_FOLDER_NAME), folderName));// 写入文件夹名称到打印流中 } String folderId = folderCursor.getString(NOTE_COLUMN_ID); - exportFolderToText(folderId, ps); + exportFolderToText(folderId, ps); // 导出当前文件夹的笔记到打印流中 } while (folderCursor.moveToNext()); } - folderCursor.close(); + folderCursor.close();// 关闭查询结果集游标 } // Export notes in root's folder @@ -264,7 +268,7 @@ public class BackupUtils { NoteColumns.TYPE + "=" + +Notes.TYPE_NOTE + " AND " + NoteColumns.PARENT_ID + "=0", null, null); - if (noteCursor != null) { + if (noteCursor != null) {//导出在根文件夹中的笔记 if (noteCursor.moveToFirst()) { do { ps.println(String.format(getFormat(FORMAT_NOTE_DATE), DateFormat.format( @@ -285,15 +289,15 @@ public class BackupUtils { /** * Get a print stream pointed to the file {@generateExportedTextFile} */ - private PrintStream getExportToTextPrintStream() { - File file = generateFileMountedOnSDcard(mContext, R.string.file_path, + private PrintStream getExportToTextPrintStream() {//私有方法，返回一个PrintStream对象，用于导出文本 + File file = generateFileMountedOnSDcard(mContext, R.string.file_path,//调用generateFileMountedOnSDcard方法生成一个文件对象，作为导出文件的路径。 R.string.file_name_txt_format); - if (file == null) { + if (file == null) {//如果文件对象为空，表示创建导出文件失败，打印错误消息并返回空 Log.e(TAG, "create file to exported failed"); return null; } mFileName = file.getName(); - mFileDirectory = mContext.getString(R.string.file_path); + mFileDirectory = mContext.getString(R.string.file_path);//将文件名和文件路径保存到相应的变量中 PrintStream ps = null; try { FileOutputStream fos = new FileOutputStream(file); @@ -321,10 +325,10 @@ public class BackupUtils { fileNameFormatResId, DateFormat.format(context.getString(R.string.format_date_ymd), System.currentTimeMillis()))); - File file = new File(sb.toString()); + File file = new File(sb.toString());//在指定的路径上创建一个新的文件 try { - if (!filedir.exists()) { + if (!filedir.exists()) {//如果文件目录不存在，则尝试创建目录 filedir.mkdir(); } if (!file.exists()) { @@ -334,7 +338,7 @@ public class BackupUtils { } catch (SecurityException e) { e.printStackTrace(); } catch (IOException e) { - e.printStackTrace(); + e.printStackTrace();//会打印错误信息并返回空 } return null;