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BackupUtils.java代码注释

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zy
lengjiao 2 years ago
parent 6385bffb6b
commit 2e41e10f8d
4 changed files with 55 additions and 28 deletions
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38
notes/tool/BackupUtils.java
Unescape View File

@ -41,8 +41,13 @@ public class BackupUtils {
// Singleton stuff
private static BackupUtils sInstance;
/*
功能描述：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）
实现过程：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。
*/
public static synchronized BackupUtils getInstance(Context context) {
if (sInstance == null) {
if (sInstance == null) {//如果当前备份不存在，则新声明一个
sInstance = new BackupUtils(context);
}
return sInstance;
@ -65,11 +70,12 @@ public class BackupUtils {
private TextExport mTextExport;
//初始化函数
private BackupUtils(Context context) {
mTextExport = new TextExport(context);
}
private static boolean externalStorageAvailable() {
private static boolean externalStorageAvailable() {//外部存储功能是否可用
return Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState());
}
@ -132,6 +138,7 @@ public class BackupUtils {
mFileDirectory = "";
}
//获取文本的组成部分
private String getFormat(int id) {
return TEXT_FORMAT[id];
}
@ -140,7 +147,7 @@ public class BackupUtils {
* Export the folder identified by folder id to text
*/
private void exportFolderToText(String folderId, PrintStream ps) {
// Query notes belong to this folder
// 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
@ -149,13 +156,13 @@ public class BackupUtils {
if (notesCursor != null) {
if (notesCursor.moveToFirst()) {
do {
// Print note's last modified date
// 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);
exportNoteToText(noteId, ps);//将文件导出到text
} while (notesCursor.moveToNext());
}
notesCursor.close();
@ -171,7 +178,7 @@ public class BackupUtils {
noteId
}, null);
if (dataCursor != 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);
@ -181,7 +188,7 @@ public class BackupUtils {
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));
}
@ -218,7 +225,7 @@ public class BackupUtils {
/**
* Note will be exported as text which is user readable
*/
public int exportToText() {
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;
@ -229,7 +236,7 @@ public class BackupUtils {
Log.e(TAG, "get print stream error");
return STATE_SYSTEM_ERROR;
}
// First export folder and its notes
// 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,
@ -257,7 +264,7 @@ public class BackupUtils {
folderCursor.close();
}
// Export notes in root's folder
// 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,
@ -298,6 +305,7 @@ public class BackupUtils {
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;
@ -314,16 +322,16 @@ public class BackupUtils {
*/
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(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 {
try {//如果这些文件不存在，则新建
if (!filedir.exists()) {
filedir.mkdir();
}
@ -336,7 +344,7 @@ public class BackupUtils {
} catch (IOException e) {
e.printStackTrace();
}
// try catch 异常处理
return null;
}
}

25
notes/tool/DataUtils.java
Unescape View File

@ -52,13 +52,14 @@ public class DataUtils {
if(id == Notes.ID_ROOT_FOLDER) {
Log.e(TAG, "Don't delete system folder root");
continue;
}
}//如果发现是根文件夹，则不删除
ContentProviderOperation.Builder builder = ContentProviderOperation
.newDelete(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id));
operationList.add(builder.build());
}
try {
ContentProviderResult[] results = resolver.applyBatch(Notes.AUTHORITY, operationList);
//数据库事务，数据库事务是由一组数据库操作序列组成，事务作为一个整体被执行
if (results == null || results.length == 0 || results[0] == null) {
Log.d(TAG, "delete notes failed, ids:" + ids.toString());
return false;
@ -94,7 +95,7 @@ public class DataUtils {
builder.withValue(NoteColumns.PARENT_ID, folderId);
builder.withValue(NoteColumns.LOCAL_MODIFIED, 1);
operationList.add(builder.build());
}
}//将ids里包含的每一列的数据逐次加入到operationList中，等待最后的批量处理
try {
ContentProviderResult[] results = resolver.applyBatch(Notes.AUTHORITY, operationList);
@ -119,7 +120,7 @@ public class DataUtils {
new String[] { "COUNT(*)" },
NoteColumns.TYPE + "=? AND " + NoteColumns.PARENT_ID + "<>?",
new String[] { String.valueOf(Notes.TYPE_FOLDER), String.valueOf(Notes.ID_TRASH_FOLER)},
null);
null); //筛选条件：源文件不为trash folder
int count = 0;
if(cursor != null) {
@ -141,11 +142,11 @@ public class DataUtils {
null,
NoteColumns.TYPE + "=? AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER,
new String [] {String.valueOf(type)},
null);
null);//查询条件：type符合，且不属于垃圾文件夹
boolean exist = false;
if (cursor != null) {
if (cursor.getCount() > 0) {
if (cursor.getCount() > 0) {//用getcount函数判断cursor是否为空
exist = true;
}
cursor.close();
@ -187,6 +188,7 @@ public class DataUtils {
" AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER +
" AND " + NoteColumns.SNIPPET + "=?",
new String[] { name }, null);
//通过名字查询文件是否存在
boolean exist = false;
if(cursor != null) {
if(cursor.getCount() > 0) {
@ -202,7 +204,7 @@ public class DataUtils {
new String[] { NoteColumns.WIDGET_ID, NoteColumns.WIDGET_TYPE },
NoteColumns.PARENT_ID + "=?",
new String[] { String.valueOf(folderId) },
null);
null);//查询条件：父ID是传入的folderId;
HashSet<AppWidgetAttribute> set = null;
if (c != null) {
@ -211,13 +213,13 @@ public class DataUtils {
do {
try {
AppWidgetAttribute widget = new AppWidgetAttribute();
widget.widgetId = c.getInt(0);
widget.widgetType = c.getInt(1);
widget.widgetId = c.getInt(0);//0对应的NoteColumns.WIDGET_ID
widget.widgetType = c.getInt(1);//1对应的NoteColumns.WIDGET_TYPE
set.add(widget);
} catch (IndexOutOfBoundsException e) {
Log.e(TAG, e.toString());
}
} while (c.moveToNext());
} while (c.moveToNext());//查询下一条
}
c.close();
}
@ -250,7 +252,7 @@ public class DataUtils {
+ CallNote.PHONE_NUMBER + ",?)",
new String [] { String.valueOf(callDate), CallNote.CONTENT_ITEM_TYPE, phoneNumber },
null);
//通过数据库操作，查询条件是（callDate和phoneNumber匹配传入参数的值）
if (cursor != null) {
if (cursor.moveToFirst()) {
try {
@ -269,7 +271,7 @@ public class DataUtils {
new String [] { NoteColumns.SNIPPET },
NoteColumns.ID + "=?",
new String [] { String.valueOf(noteId)},
null);
null);//查询条件：noteId
if (cursor != null) {
String snippet = "";
@ -282,6 +284,7 @@ public class DataUtils {
throw new IllegalArgumentException("Note is not found with id: " + noteId);
}
//对字符串进行格式处理，将字符串两头的空格去掉，同时将换行符去掉
public static String getFormattedSnippet(String snippet) {
if (snippet != null) {
snippet = snippet.trim();

4
notes/tool/GTaskStringUtils.java
Unescape View File

@ -13,9 +13,9 @@
* See the License for the specific language governing permissions and
* limitations under the License.
*/
//简介：定义了很多的静态字符串，目的就是为了提供jsonObject中相应字符串的"key"。把这些静态的定义单独写到了一个类里面，这是非常好的编程规范
package net.micode.notes.tool;
//这个类就是定义了一堆static string，实际就是为jsonObject提供Key，把这些定义全部写到一个类里，方便查看管理，是一个非常好的编程习惯
public class GTaskStringUtils {
public final static String GTASK_JSON_ACTION_ID = "action_id";

16
notes/tool/ResourceParser.java
Unescape View File

@ -15,6 +15,20 @@
*/
package net.micode.notes.tool;
/*简介：字面意义是资源分析器，实际上就是获取资源并且在程序中使用，比如颜色图片等
* 实现方法：主要利用R.java这个类，其中包括
* R.id 组件资源引用
* R.drawable 图片资源 （被使用）
* R.layout 布局资源
* R.menu 菜单资源
* R.String 文字资源
* R.style 主题资源 （被使用）
* 在按顺序设置好相应的id后，就可以编写简单的getXXX函数获取需要的资源
*
* 特殊的变量 ：
* @BG_DEFAULT_COLOR 默认背景颜色（黄）
* BG_DEFAULT_FONT_SIZE 默认文本大小（中）
*/
import android.content.Context;
import android.preference.PreferenceManager;
@ -65,6 +79,7 @@ public class ResourceParser {
}
}
//直接获取默认的背景颜色。看不太懂，这个PREFERENCE_SET_BG_COLOR_KEY是个final string,也就是说getBoolean肯定执行else
public static int getDefaultBgId(Context context) {
if (PreferenceManager.getDefaultSharedPreferences(context).getBoolean(
NotesPreferenceActivity.PREFERENCE_SET_BG_COLOR_KEY, false)) {
@ -162,6 +177,7 @@ public class ResourceParser {
R.style.TextAppearanceSuper
};
//这里有一个容错的函数，防止输入的id大于资源总量，若如此，则自动返回默认的设置结果
public static int getTexAppearanceResource(int id) {
/**
* HACKME: Fix bug of store the resource id in shared preference.

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