README.md

@@ -1,2 +0,0 @@
-# xiaomibianqian
-# 所以到底要干嘛？

src/MiNotes-master/app/src/main/java/net/micode/notes/data/Contact.java

@@ -14,60 +14,72 @@
  * limitations under the License.
  */
 
-package net.micode.notes.data;
-
-import android.content.Context;
-import android.database.Cursor;
-import android.provider.ContactsContract.CommonDataKinds.Phone;
-import android.provider.ContactsContract.Data;
-import android.telephony.PhoneNumberUtils;
-import android.util.Log;
-
-import java.util.HashMap;
-
-public class Contact {
-    private static HashMap<String, String> sContactCache;
-    private static final String TAG = "Contact";
-
-    private static final String CALLER_ID_SELECTION = "PHONE_NUMBERS_EQUAL(" + Phone.NUMBER
-    + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'"
-    + " AND " + Data.RAW_CONTACT_ID + " IN "
-            + "(SELECT raw_contact_id "
-            + " FROM phone_lookup"
-            + " WHERE min_match = '+')";
-
-    public static String getContact(Context context, String phoneNumber) {
-        if(sContactCache == null) {
-            sContactCache = new HashMap<String, String>();
-        }
-
-        if(sContactCache.containsKey(phoneNumber)) {
-            return sContactCache.get(phoneNumber);
-        }
-
-        String selection = CALLER_ID_SELECTION.replace("+",
-                PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));
-        Cursor cursor = context.getContentResolver().query(
-                Data.CONTENT_URI,
-                new String [] { Phone.DISPLAY_NAME },
-                selection,
-                new String[] { phoneNumber },
-                null);
-
-        if (cursor != null && cursor.moveToFirst()) {
-            try {
-                String name = cursor.getString(0);
-                sContactCache.put(phoneNumber, name);
-                return name;
-            } catch (IndexOutOfBoundsException e) {
-                Log.e(TAG, " Cursor get string error " + e.toString());
-                return null;
-            } finally {
-                cursor.close();
-            }
-        } else {
-            Log.d(TAG, "No contact matched with number:" + phoneNumber);
-            return null;
-        }
-    }
-}
+ package net.micode.notes.data;
+ 
+ import android.content.Context;
+  
+ import android.database.Cursor;
+ import android.provider.ContactsContract.CommonDataKinds.Phone;
+ import android.provider.ContactsContract.Data;
+ import android.telephony.PhoneNumberUtils;
+ import android.util.Log;
+  
+ import java.util.HashMap;
+ //change
+ public class Contact { //联系人
+     private static HashMap<String, String> sContactCache;
+     private static final String TAG = "Contact";
+  
+     // 定义字符串CALLER_ID_SELECTION
+     private static final String CALLER_ID_SELECTION = "PHONE_NUMBERS_EQUAL(" 
+  
+ + Phone.NUMBER
+     + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'"
+     + " AND " + Data.RAW_CONTACT_ID + " IN "
+             + "(SELECT raw_contact_id "
+             + " FROM phone_lookup"
+             + " WHERE min_match = '+')";
+     
+     // 获取联系人
+     public static String getContact(Context context, String phoneNumber) {
+         if(sContactCache == null) {
+             sContactCache = new HashMap<String, String>();
+         }
+         
+         // 查找HashMap中是否已有phoneNumber信息
+         if(sContactCache.containsKey(phoneNumber)) {
+             return sContactCache.get(phoneNumber);
+         }
+  
+         String selection = CALLER_ID_SELECTION.replace("+",
+                 PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));
+         // 查找数据库中phoneNumber的信息
+         Cursor cursor = context.getContentResolver().query(
+                 Data.CONTENT_URI,
+                 new String [] { Phone.DISPLAY_NAME },
+                 selection,
+                 new String[] { phoneNumber },
+                 null);
+         
+         // 判定查询结果 
+         // moveToFirst()返回第一条
+         if (cursor != null && cursor.moveToFirst()) {
+             try {
+             // 找到相关信息
+                 String name = cursor.getString(0);
+                 sContactCache.put(phoneNumber, name);
+                 return name;
+             // 异常
+             } catch (IndexOutOfBoundsException e) {
+                 Log.e(TAG, " Cursor get string error " + e.toString());
+                 return null;
+             } finally {
+                 cursor.close();
+             }
+             // 未找到相关信息
+         } else {
+             Log.d(TAG, "No contact matched with number:" + phoneNumber);
+             return null;
+         }
+     }
+ }

src/MiNotes-master/app/src/main/java/net/micode/notes/data/Notes.java

@@ -15,15 +15,19 @@
  */
 
 package net.micode.notes.data;
-
+ 
+import android.content.ContentUris;
 import android.net.Uri;
+// Notes 类中定义了很多常量，这些常量大多是int型和string型
 public class Notes {
     public static final String AUTHORITY = "micode_notes";
     public static final String TAG = "Notes";
+    
+    //以下三个常量对NoteColumns.TYPE的值进行设置时会用到
     public static final int TYPE_NOTE     = 0;
     public static final int TYPE_FOLDER   = 1;
     public static final int TYPE_SYSTEM   = 2;
-
+ 
     /**
      * Following IDs are system folders' identifiers
      * {@link Notes#ID_ROOT_FOLDER } is default folder
@@ -34,246 +38,282 @@ public class Notes {
     public static final int ID_TEMPARAY_FOLDER = -1;
     public static final int ID_CALL_RECORD_FOLDER = -2;
     public static final int ID_TRASH_FOLER = -3;
-
-    public static final String INTENT_EXTRA_ALERT_DATE = "net.micode.notes.alert_date";
-    public static final String INTENT_EXTRA_BACKGROUND_ID = "net.micode.notes.background_color_id";
-    public static final String INTENT_EXTRA_WIDGET_ID = "net.micode.notes.widget_id";
-    public static final String INTENT_EXTRA_WIDGET_TYPE = "net.micode.notes.widget_type";
-    public static final String INTENT_EXTRA_FOLDER_ID = "net.micode.notes.folder_id";
-    public static final String INTENT_EXTRA_CALL_DATE = "net.micode.notes.call_date";
-
+ 
+    public static final String INTENT_EXTRA_ALERT_DATE = 
+ 
+"net.micode.notes.alert_date";
+    public static final String INTENT_EXTRA_BACKGROUND_ID = 
+ 
+"net.micode.notes.background_color_id";
+    public static final String INTENT_EXTRA_WIDGET_ID = 
+ 
+"net.micode.notes.widget_id";
+    public static final String INTENT_EXTRA_WIDGET_TYPE = 
+ 
+"net.micode.notes.widget_type";
+    public static final String INTENT_EXTRA_FOLDER_ID = 
+ 
+"net.micode.notes.folder_id";
+    public static final String INTENT_EXTRA_CALL_DATE = 
+ 
+"net.micode.notes.call_date";
+ 
     public static final int TYPE_WIDGET_INVALIDE      = -1;
     public static final int TYPE_WIDGET_2X            = 0;
     public static final int TYPE_WIDGET_4X            = 1;
-
+ 
     public static class DataConstants {
         public static final String NOTE = TextNote.CONTENT_ITEM_TYPE;
         public static final String CALL_NOTE = CallNote.CONTENT_ITEM_TYPE;
     }
-
+ 
     /**
      * Uri to query all notes and folders
      */
-    public static final Uri CONTENT_NOTE_URI = Uri.parse("content://" + AUTHORITY + "/note");
-
+    public static final Uri CONTENT_NOTE_URI = Uri.parse("content://" + 
+ 
+AUTHORITY + "/note");//定义查询便签和文件夹的指针。
+ 
+//    public static final Uri my_URI = ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI , 10);
+   
     /**
      * Uri to query data
      */
-    public static final Uri CONTENT_DATA_URI = Uri.parse("content://" + AUTHORITY + "/data");
-
+    public static final Uri CONTENT_DATA_URI = Uri.parse("content://" + 
+ 
+AUTHORITY + "/data");//定义查找数据的指针。
+ 
+    // 定义NoteColumns的常量,用于后面创建数据库的表头
     public interface NoteColumns {
         /**
          * The unique ID for a row
          * <P> Type: INTEGER (long) </P>
          */
         public static final String ID = "_id";
-
+ 
         /**
          * The parent's id for note or folder
          * <P> Type: INTEGER (long) </P>
          */
-        public static final String PARENT_ID = "parent_id";
-
+        public static final String PARENT_ID = "parent_id";//为什么会有parent_id
+ 
         /**
          * Created data for note or folder
          * <P> Type: INTEGER (long) </P>
          */
         public static final String CREATED_DATE = "created_date";
-
+ 
         /**
          * Latest modified date
          * <P> Type: INTEGER (long) </P>
          */
         public static final String MODIFIED_DATE = "modified_date";
-
-
+ 
+ 
         /**
          * Alert date
          * <P> Type: INTEGER (long) </P>
          */
         public static final String ALERTED_DATE = "alert_date";
-
+ 
         /**
          * Folder's name or text content of note
          * <P> Type: TEXT </P>
          */
         public static final String SNIPPET = "snippet";
-
+ 
         /**
          * Note's widget id
          * <P> Type: INTEGER (long) </P>
          */
         public static final String WIDGET_ID = "widget_id";
-
+ 
         /**
          * Note's widget type
          * <P> Type: INTEGER (long) </P>
          */
         public static final String WIDGET_TYPE = "widget_type";
-
+ 
         /**
          * Note's background color's id
          * <P> Type: INTEGER (long) </P>
          */
         public static final String BG_COLOR_ID = "bg_color_id";
-
+ 
         /**
          * For text note, it doesn't has attachment, for multi-media
          * note, it has at least one attachment
          * <P> Type: INTEGER </P>
          */
         public static final String HAS_ATTACHMENT = "has_attachment";
-
+ 
         /**
          * Folder's count of notes
          * <P> Type: INTEGER (long) </P>
          */
         public static final String NOTES_COUNT = "notes_count";
-
+ 
         /**
          * The file type: folder or note
          * <P> Type: INTEGER </P>
          */
         public static final String TYPE = "type";
-
+ 
         /**
          * The last sync id
          * <P> Type: INTEGER (long) </P>
          */
-        public static final String SYNC_ID = "sync_id";
-
+        public static final String SYNC_ID = "sync_id";//同步
+ 
         /**
          * Sign to indicate local modified or not
          * <P> Type: INTEGER </P>
          */
         public static final String LOCAL_MODIFIED = "local_modified";
-
+ 
         /**
          * Original parent id before moving into temporary folder
          * <P> Type : INTEGER </P>
          */
         public static final String ORIGIN_PARENT_ID = "origin_parent_id";
-
+ 
         /**
          * The gtask id
          * <P> Type : TEXT </P>
          */
         public static final String GTASK_ID = "gtask_id";
-
+ 
         /**
          * The version code
          * <P> Type : INTEGER (long) </P>
          */
         public static final String VERSION = "version";
-    }
-
+    }//这些常量主要是定义便签的属性的。
+ 
+    // 定义DataColumns的常量,用于后面创建数据库的表头
     public interface DataColumns {
         /**
          * The unique ID for a row
          * <P> Type: INTEGER (long) </P>
          */
         public static final String ID = "_id";
-
+ 
         /**
          * The MIME type of the item represented by this row.
          * <P> Type: Text </P>
          */
         public static final String MIME_TYPE = "mime_type";
-
+ 
         /**
          * The reference id to note that this data belongs to
          * <P> Type: INTEGER (long) </P>
          */
         public static final String NOTE_ID = "note_id";
-
+ 
         /**
          * Created data for note or folder
          * <P> Type: INTEGER (long) </P>
          */
         public static final String CREATED_DATE = "created_date";
-
+ 
         /**
          * Latest modified date
          * <P> Type: INTEGER (long) </P>
          */
         public static final String MODIFIED_DATE = "modified_date";
-
+ 
         /**
          * Data's content
          * <P> Type: TEXT </P>
          */
         public static final String CONTENT = "content";
-
-
+ 
+ 
         /**
-         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, 
+used for
          * integer data type
          * <P> Type: INTEGER </P>
          */
         public static final String DATA1 = "data1";
-
+ 
         /**
-         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, 
+used for
          * integer data type
          * <P> Type: INTEGER </P>
          */
         public static final String DATA2 = "data2";
-
+ 
         /**
-         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, 
+used for
          * TEXT data type
          * <P> Type: TEXT </P>
          */
         public static final String DATA3 = "data3";
-
+ 
         /**
-         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, 
+used for
          * TEXT data type
          * <P> Type: TEXT </P>
          */
         public static final String DATA4 = "data4";
-
+ 
         /**
-         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, 
+used for
          * TEXT data type
          * <P> Type: TEXT </P>
          */
         public static final String DATA5 = "data5";
-    }
-
+    }//主要是定义存储便签内容数据的
     public static final class TextNote implements DataColumns {
         /**
          * Mode to indicate the text in check list mode or not
          * <P> Type: Integer 1:check list mode 0: normal mode </P>
          */
         public static final String MODE = DATA1;
-
+ 
         public static final int MODE_CHECK_LIST = 1;
-
-        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/text_note";
-
-        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/text_note";
-
-        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/text_note");
-    }
-
+ 
+        public static final String CONTENT_TYPE = 
+ 
+"vnd.android.cursor.dir/text_note";
+ 
+        public static final String CONTENT_ITEM_TYPE = 
+ 
+"vnd.android.cursor.item/text_note";
+ 
+        public static final Uri CONTENT_URI = Uri.parse("content://" + 
+ 
+AUTHORITY + "/text_note");
+    }//文本内容的数据结构
+ 
     public static final class CallNote implements DataColumns {
         /**
          * Call date for this record
          * <P> Type: INTEGER (long) </P>
          */
         public static final String CALL_DATE = DATA1;
-
+ 
         /**
          * Phone number for this record
          * <P> Type: TEXT </P>
          */
         public static final String PHONE_NUMBER = DATA3;
-
-        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/call_note";
-
-        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/call_note";
-
-        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/call_note");
-    }
-}
+ 
+        public static final String CONTENT_TYPE = 
+ 
+"vnd.android.cursor.dir/call_note";
+ 
+        public static final String CONTENT_ITEM_TYPE = 
+ 
+"vnd.android.cursor.item/call_note";
+ 
+        public static final Uri CONTENT_URI = Uri.parse("content://" + 
+ 
+AUTHORITY + "/call_note");
+    }//电话内容的数据结构
+}

src/MiNotes-master/app/src/main/java/net/micode/notes/data/NotesDatabaseHelper.java

@@ -15,33 +15,33 @@
  */
 
 package net.micode.notes.data;
-
-import android.content.ContentValues;
-import android.content.Context;
-import android.database.sqlite.SQLiteDatabase;
-import android.database.sqlite.SQLiteOpenHelper;
+ 
+import android.content.ContentValues;//就是用于保存一些数据（string boolean byte double float int long short ...）信息，这些信息可以被数据库操作时使用。
+import android.content.Context;//加载和访问资源。（android中主要是这两个功能，但是这里具体不清楚）
+import android.database.sqlite.SQLiteDatabase;//主要提供了对应于添加、删除、更新、查询的操作方法： insert()、delete()、update()和query()。配合content.values
+import android.database.sqlite.SQLiteOpenHelper;//用来管理数据的创建和版本更新
 import android.util.Log;
-
+ 
 import net.micode.notes.data.Notes.DataColumns;
 import net.micode.notes.data.Notes.DataConstants;
 import net.micode.notes.data.Notes.NoteColumns;
-
-
+//数据库操作，用SQLOpenhelper,对一些note和文件进行数据库的操作，比如删除文件后，将文件里的note也相应删除
+ 
 public class NotesDatabaseHelper extends SQLiteOpenHelper {
     private static final String DB_NAME = "note.db";
-
+ 
     private static final int DB_VERSION = 4;
-
-    public interface TABLE {
+ 
+    public interface TABLE {    //接口，分成note和data，在后面的程序里分别使用过
         public static final String NOTE = "note";
-
+ 
         public static final String DATA = "data";
     }
-
+ 
     private static final String TAG = "NotesDatabaseHelper";
-
+ 
     private static NotesDatabaseHelper mInstance;
-
+ 
     private static final String CREATE_NOTE_TABLE_SQL =
         "CREATE TABLE " + TABLE.NOTE + "(" +
             NoteColumns.ID + " INTEGER PRIMARY KEY," +
@@ -61,8 +61,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
             NoteColumns.ORIGIN_PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
             NoteColumns.GTASK_ID + " TEXT NOT NULL DEFAULT ''," +
             NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0" +
-        ")";
-
+        ")";//数据库中需要存储的项目的名称，就相当于创建一个表格的表头的内容。
+ 
     private static final String CREATE_DATA_TABLE_SQL =
         "CREATE TABLE " + TABLE.DATA + "(" +
             DataColumns.ID + " INTEGER PRIMARY KEY," +
@@ -76,12 +76,12 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
             DataColumns.DATA3 + " TEXT NOT NULL DEFAULT ''," +
             DataColumns.DATA4 + " TEXT NOT NULL DEFAULT ''," +
             DataColumns.DATA5 + " TEXT NOT NULL DEFAULT ''" +
-        ")";
-
+        ")";//和上面的功能一样，主要是存储的项目不同
+ 
     private static final String CREATE_DATA_NOTE_ID_INDEX_SQL =
         "CREATE INDEX IF NOT EXISTS note_id_index ON " +
-        TABLE.DATA + "(" + DataColumns.NOTE_ID + ");";
-
+        TABLE.DATA + "(" + DataColumns.NOTE_ID + ");";//存储便签编号的一个数据表格
+ 
     /**
      * Increase folder's note count when move note to the folder
      */
@@ -92,8 +92,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         "  UPDATE " + TABLE.NOTE +
         "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
         "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
-        " END";
-
+        " END";//在文件夹中移入一个Note之后需要更改的数据的表格。
+ 
     /**
      * Decrease folder's note count when move note from folder
      */
@@ -105,8 +105,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
         "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
         "  AND " + NoteColumns.NOTES_COUNT + ">0" + ";" +
-        " END";
-
+        " END";//在文件夹中移出一个Note之后需要更改的数据的表格。
+ 
     /**
      * Increase folder's note count when insert new note to the folder
      */
@@ -117,8 +117,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         "  UPDATE " + TABLE.NOTE +
         "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
         "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
-        " END";
-
+        " END";//在文件夹中插入一个Note之后需要更改的数据的表格。
+ 
     /**
      * Decrease folder's note count when delete note from the folder
      */
@@ -130,8 +130,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
         "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
         "  AND " + NoteColumns.NOTES_COUNT + ">0;" +
-        " END";
-
+        " END";//在文件夹中删除一个Note之后需要更改的数据的表格。
+ 
     /**
      * Update note's content when insert data with type {@link DataConstants#NOTE}
      */
@@ -143,8 +143,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         "  UPDATE " + TABLE.NOTE +
         "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
         "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
-        " END";
-
+        " END";//在文件夹中对一个Note导入新的数据之后需要更改的数据的表格。
+ 
     /**
      * Update note's content when data with {@link DataConstants#NOTE} type has changed
      */
@@ -156,8 +156,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         "  UPDATE " + TABLE.NOTE +
         "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
         "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
-        " END";
-
+        " END";//Note数据被修改后需要更改的数据的表格。
+ 
     /**
      * Update note's content when data with {@link DataConstants#NOTE} type has deleted
      */
@@ -169,8 +169,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         "  UPDATE " + TABLE.NOTE +
         "   SET " + NoteColumns.SNIPPET + "=''" +
         "  WHERE " + NoteColumns.ID + "=old." + DataColumns.NOTE_ID + ";" +
-        " END";
-
+        " END";//Note数据被删除后需要更改的数据的表格。
+ 
     /**
      * Delete datas belong to note which has been deleted
      */
@@ -180,8 +180,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         " BEGIN" +
         "  DELETE FROM " + TABLE.DATA +
         "   WHERE " + DataColumns.NOTE_ID + "=old." + NoteColumns.ID + ";" +
-        " END";
-
+        " END";//删除已删除的便签的数据后需要更改的数据的表格。
+ 
     /**
      * Delete notes belong to folder which has been deleted
      */
@@ -191,8 +191,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         " BEGIN" +
         "  DELETE FROM " + TABLE.NOTE +
         "   WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
-        " END";
-
+        " END";//删除已删除的文件夹的便签后需要更改的数据的表格。
+ 
     /**
      * Move notes belong to folder which has been moved to trash folder
      */
@@ -204,19 +204,19 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         "  UPDATE " + TABLE.NOTE +
         "   SET " + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER +
         "  WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
-        " END";
-
+        " END";//还原垃圾桶中便签后需要更改的数据的表格。
+ 
     public NotesDatabaseHelper(Context context) {
         super(context, DB_NAME, null, DB_VERSION);
-    }
-
+    }//构造函数，传入数据库的名称和版本
+ 
     public void createNoteTable(SQLiteDatabase db) {
         db.execSQL(CREATE_NOTE_TABLE_SQL);
         reCreateNoteTableTriggers(db);
         createSystemFolder(db);
         Log.d(TAG, "note table has been created");
-    }
-
+    }//创建表格（用来存储标签属性）
+ 
     private void reCreateNoteTableTriggers(SQLiteDatabase db) {
         db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_update");
         db.execSQL("DROP TRIGGER IF EXISTS decrease_folder_count_on_update");
@@ -225,7 +225,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_insert");
         db.execSQL("DROP TRIGGER IF EXISTS folder_delete_notes_on_delete");
         db.execSQL("DROP TRIGGER IF EXISTS folder_move_notes_on_trash");
-
+ 
         db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER);
         db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER);
         db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER);
@@ -233,18 +233,19 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER);
         db.execSQL(FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER);
         db.execSQL(FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER);
-    }
-
+    }//execSQL是数据库操作的API，主要是更改行为的SQL语句。
+    //在这里主要是用来重新创建上述定义的表格用的，先删除原来有的数据库的触发器再重新创建新的数据库
+ 
     private void createSystemFolder(SQLiteDatabase db) {
         ContentValues values = new ContentValues();
-
+ 
         /**
          * call record foler for call notes
          */
         values.put(NoteColumns.ID, Notes.ID_CALL_RECORD_FOLDER);
         values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
         db.insert(TABLE.NOTE, null, values);
-
+ 
         /**
          * root folder which is default folder
          */
@@ -252,7 +253,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         values.put(NoteColumns.ID, Notes.ID_ROOT_FOLDER);
         values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
         db.insert(TABLE.NOTE, null, values);
-
+ 
         /**
          * temporary folder which is used for moving note
          */
@@ -260,7 +261,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         values.put(NoteColumns.ID, Notes.ID_TEMPARAY_FOLDER);
         values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
         db.insert(TABLE.NOTE, null, values);
-
+ 
         /**
          * create trash folder
          */
@@ -268,78 +269,80 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
         values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
         db.insert(TABLE.NOTE, null, values);
-    }
-
+    }//创建几个系统文件夹
+ 
     public void createDataTable(SQLiteDatabase db) {
         db.execSQL(CREATE_DATA_TABLE_SQL);
         reCreateDataTableTriggers(db);
         db.execSQL(CREATE_DATA_NOTE_ID_INDEX_SQL);
         Log.d(TAG, "data table has been created");
-    }
-
+    }//创建表格（用来存储标签内容）
+ 
     private void reCreateDataTableTriggers(SQLiteDatabase db) {
         db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_insert");
         db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_update");
         db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_delete");
-
+ 
         db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER);
         db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER);
         db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER);
-    }
-
+    }//同上面的execSQL
+ 
     static synchronized NotesDatabaseHelper getInstance(Context context) {
         if (mInstance == null) {
             mInstance = new NotesDatabaseHelper(context);
         }
         return mInstance;
-    }
-
+    }//上网查是为解决同一时刻只能有一个线程执行.
+     //在写程序库代码时，有时有一个类需要被所有的其它类使用，
+     //但又要求这个类只能被实例化一次，是个服务类，定义一次，其它类使用同一个这个类的实例
+ 
     @Override
     public void onCreate(SQLiteDatabase db) {
         createNoteTable(db);
         createDataTable(db);
-    }
-
+    }//实现两个表格（上面创建的两个表格）
+ 
     @Override
     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
         boolean reCreateTriggers = false;
         boolean skipV2 = false;
-
+ 
         if (oldVersion == 1) {
             upgradeToV2(db);
             skipV2 = true; // this upgrade including the upgrade from v2 to v3
             oldVersion++;
         }
-
+ 
         if (oldVersion == 2 && !skipV2) {
             upgradeToV3(db);
             reCreateTriggers = true;
             oldVersion++;
         }
-
+ 
         if (oldVersion == 3) {
             upgradeToV4(db);
             oldVersion++;
         }
-
+ 
         if (reCreateTriggers) {
             reCreateNoteTableTriggers(db);
             reCreateDataTableTriggers(db);
         }
-
+ 
         if (oldVersion != newVersion) {
             throw new IllegalStateException("Upgrade notes database to version " + newVersion
                     + "fails");
         }
-    }
-
+    }//数据库版本的更新（数据库内容的更改）
+ 
     private void upgradeToV2(SQLiteDatabase db) {
         db.execSQL("DROP TABLE IF EXISTS " + TABLE.NOTE);
         db.execSQL("DROP TABLE IF EXISTS " + TABLE.DATA);
         createNoteTable(db);
         createDataTable(db);
-    }
-
+    }//更新到V2版本
+ 
     private void upgradeToV3(SQLiteDatabase db) {
         // drop unused triggers
         db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_insert");
@@ -353,10 +356,10 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
         values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
         db.insert(TABLE.NOTE, null, values);
-    }
-
+    }//更新到V3版本
+ 
     private void upgradeToV4(SQLiteDatabase db) {
         db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.VERSION
                 + " INTEGER NOT NULL DEFAULT 0");
-    }
+    }//更新到V4版本
 }

src/MiNotes-master/app/src/main/java/net/micode/notes/data/NotesProvider.java

@@ -15,8 +15,7 @@
  */
 
 package net.micode.notes.data;
-
-
+ 
 import android.app.SearchManager;
 import android.content.ContentProvider;
 import android.content.ContentUris;
@@ -28,30 +27,38 @@ import android.database.sqlite.SQLiteDatabase;
 import android.net.Uri;
 import android.text.TextUtils;
 import android.util.Log;
-
+ 
 import net.micode.notes.R;
 import net.micode.notes.data.Notes.DataColumns;
 import net.micode.notes.data.Notes.NoteColumns;
 import net.micode.notes.data.NotesDatabaseHelper.TABLE;
-
-
+//为存储和获取数据提供接口。可以在不同的应用程序之间共享数据
+//ContentProvider提供的方法
+//query：查询
+//insert：插入
+//update：更新
+//delete：删除
+//getType：得到数据类型
 public class NotesProvider extends ContentProvider {
+	// UriMatcher用于匹配Uri
     private static final UriMatcher mMatcher;
-
+ 
     private NotesDatabaseHelper mHelper;
-
+ 
     private static final String TAG = "NotesProvider";
-
+ 
     private static final int URI_NOTE            = 1;
     private static final int URI_NOTE_ITEM       = 2;
     private static final int URI_DATA            = 3;
     private static final int URI_DATA_ITEM       = 4;
-
+ 
     private static final int URI_SEARCH          = 5;
     private static final int URI_SEARCH_SUGGEST  = 6;
-
+ 
     static {
+    	// 创建UriMatcher时，调用UriMatcher(UriMatcher.NO_MATCH)表示不匹配任何路径的返回码
         mMatcher = new UriMatcher(UriMatcher.NO_MATCH);
+        // 把需要匹配Uri路径全部给注册上
         mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE);
         mMatcher.addURI(Notes.AUTHORITY, "note/#", URI_NOTE_ITEM);
         mMatcher.addURI(Notes.AUTHORITY, "data", URI_DATA);
@@ -60,11 +67,12 @@ public class NotesProvider extends ContentProvider {
         mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY, URI_SEARCH_SUGGEST);
         mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY + "/*", URI_SEARCH_SUGGEST);
     }
-
+ 
     /**
      * x'0A' represents the '\n' character in sqlite. For title and content in the search result,
      * we will trim '\n' and white space in order to show more information.
      */
+    // 声明 NOTES_SEARCH_PROJECTION
     private static final String NOTES_SEARCH_PROJECTION = NoteColumns.ID + ","
         + NoteColumns.ID + " AS " + SearchManager.SUGGEST_COLUMN_INTENT_EXTRA_DATA + ","
         + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_1 + ","
@@ -72,26 +80,32 @@ public class NotesProvider extends ContentProvider {
         + R.drawable.search_result + " AS " + SearchManager.SUGGEST_COLUMN_ICON_1 + ","
         + "'" + Intent.ACTION_VIEW + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_ACTION + ","
         + "'" + Notes.TextNote.CONTENT_TYPE + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_DATA;
-
+    // 声明NOTES_SNIPPET_SEARCH_QUERY
     private static String NOTES_SNIPPET_SEARCH_QUERY = "SELECT " + NOTES_SEARCH_PROJECTION
         + " FROM " + TABLE.NOTE
         + " WHERE " + NoteColumns.SNIPPET + " LIKE ?"
         + " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER
         + " AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE;
-
+ 
     @Override
+    // Context只有在onCreate()中才被初始化
+    // 对mHelper进行实例化
     public boolean onCreate() {
         mHelper = NotesDatabaseHelper.getInstance(getContext());
         return true;
     }
-
+ 
     @Override
+    // 查询uri在数据库中对应的位置
     public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
             String sortOrder) {
         Cursor c = null;
+        // 获取可读数据库
         SQLiteDatabase db = mHelper.getReadableDatabase();
         String id = null;
+        // 匹配查找uri
         switch (mMatcher.match(uri)) {
+        	// 对于不同的匹配值，在数据库中查找相应的条目
             case URI_NOTE:
                 c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null,
                         sortOrder);
@@ -113,23 +127,26 @@ public class NotesProvider extends ContentProvider {
             case URI_SEARCH:
             case URI_SEARCH_SUGGEST:
                 if (sortOrder != null || projection != null) {
+                	// 不合法的参数异常
                     throw new IllegalArgumentException(
                             "do not specify sortOrder, selection, selectionArgs, or projection" + "with this query");
                 }
-
+ 
                 String searchString = null;
                 if (mMatcher.match(uri) == URI_SEARCH_SUGGEST) {
                     if (uri.getPathSegments().size() > 1) {
+                    	// getPathSegments()方法得到一个String的List，
+                    	// 在uri.getPathSegments().get(1)为第2个元素
                         searchString = uri.getPathSegments().get(1);
                     }
                 } else {
                     searchString = uri.getQueryParameter("pattern");
                 }
-
+ 
                 if (TextUtils.isEmpty(searchString)) {
                     return null;
                 }
-
+ 
                 try {
                     searchString = String.format("%%%s%%", searchString);
                     c = db.rawQuery(NOTES_SNIPPET_SEARCH_QUERY,
@@ -139,6 +156,7 @@ public class NotesProvider extends ContentProvider {
                 }
                 break;
             default:
+            	// 抛出异常
                 throw new IllegalArgumentException("Unknown URI " + uri);
         }
         if (c != null) {
@@ -146,15 +164,19 @@ public class NotesProvider extends ContentProvider {
         }
         return c;
     }
-
+ 
     @Override
+    // 插入一个uri
     public Uri insert(Uri uri, ContentValues values) {
+    	// 获得可写的数据库
         SQLiteDatabase db = mHelper.getWritableDatabase();
         long dataId = 0, noteId = 0, insertedId = 0;
         switch (mMatcher.match(uri)) {
+        	// 新增一个条目
             case URI_NOTE:
                 insertedId = noteId = db.insert(TABLE.NOTE, null, values);
                 break;
+            // 如果存在，查找NOTE_ID
             case URI_DATA:
                 if (values.containsKey(DataColumns.NOTE_ID)) {
                     noteId = values.getAsLong(DataColumns.NOTE_ID);
@@ -163,28 +185,33 @@ public class NotesProvider extends ContentProvider {
                 }
                 insertedId = dataId = db.insert(TABLE.DATA, null, values);
                 break;
-            default:
+           default:
                 throw new IllegalArgumentException("Unknown URI " + uri);
         }
         // Notify the note uri
+        // notifyChange获得一个ContextResolver对象并且更新里面的内容
         if (noteId > 0) {
             getContext().getContentResolver().notifyChange(
                     ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId), null);
         }
-
+ 
         // Notify the data uri
         if (dataId > 0) {
             getContext().getContentResolver().notifyChange(
                     ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId), null);
         }
-
+ 
+        // 返回插入的uri的路径
         return ContentUris.withAppendedId(uri, insertedId);
     }
-
+ 
     @Override
+    // 删除一个uri
     public int delete(Uri uri, String selection, String[] selectionArgs) {
+    	//Uri代表要操作的数据，Android上可用的每种资源 -包括 图像、视频片段、音频资源等都可以用Uri来表示。
         int count = 0;
         String id = null;
+        // 获得可写的数据库
         SQLiteDatabase db = mHelper.getWritableDatabase();
         boolean deleteData = false;
         switch (mMatcher.match(uri)) {
@@ -226,8 +253,9 @@ public class NotesProvider extends ContentProvider {
         }
         return count;
     }
-
+ 
     @Override
+    // 更新一个uri
     public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
         int count = 0;
         String id = null;
@@ -257,7 +285,7 @@ public class NotesProvider extends ContentProvider {
             default:
                 throw new IllegalArgumentException("Unknown URI " + uri);
         }
-
+ 
         if (count > 0) {
             if (updateData) {
                 getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
@@ -266,11 +294,13 @@ public class NotesProvider extends ContentProvider {
         }
         return count;
     }
-
+    
+    // 将字符串解析成规定格式
     private String parseSelection(String selection) {
         return (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : "");
     }
-
+    
+    //增加一个noteVersion
     private void increaseNoteVersion(long id, String selection, String[] selectionArgs) {
         StringBuilder sql = new StringBuilder(120);
         sql.append("UPDATE ");
@@ -278,7 +308,7 @@ public class NotesProvider extends ContentProvider {
         sql.append(" SET ");
         sql.append(NoteColumns.VERSION);
         sql.append("=" + NoteColumns.VERSION + "+1 ");
-
+ 
         if (id > 0 || !TextUtils.isEmpty(selection)) {
             sql.append(" WHERE ");
         }
@@ -292,14 +322,15 @@ public class NotesProvider extends ContentProvider {
             }
             sql.append(selectString);
         }
-
+        
+        // execSQL()方法可以执行insert、delete、update和CREATE TABLE之类有更改行为的SQL语句
         mHelper.getWritableDatabase().execSQL(sql.toString());
     }
-
+ 
     @Override
     public String getType(Uri uri) {
         // TODO Auto-generated method stub
         return null;
     }
-
-}
+ 
+}

src/MiNotes-master/app/src/main/java/net/micode/notes/tool/BackupUtils.java

@@ -35,56 +35,60 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.PrintStream;
 
-
+ 
 public class BackupUtils {
-    private static final String TAG = "BackupUtils";
+    private static final String TAG = "BackupUtils";    
     // Singleton stuff
-    private static BackupUtils sInstance;
-
+    private static BackupUtils sInstance;   
+ 
     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
-    public static final int STATE_SD_CARD_UNMOUONTED           = 0;
-    // The backup file not exist
+    // 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
+    // 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
+    // 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
+    // Backup or restore success  成功存储
     public static final int STATE_SUCCESS                      = 4;
-
+ 
     private TextExport mTextExport;
-
-    private BackupUtils(Context context) {
+ 
+    private BackupUtils(Context context) {  //初始化函数
         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());
     }
-
+ 
     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,
@@ -92,13 +96,13 @@ public class BackupUtils {
                 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,
@@ -107,71 +111,71 @@ public class BackupUtils {
                 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 = "";
+            mFileName = "";    //为什么为空?
             mFileDirectory = "";
         }
-
-        private String getFormat(int id) {
+ 
+        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
+        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 != 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();
             }
         }
-
+ 
         /**
          * Export note identified by id to a print stream
          */
-        private void exportNoteToText(String noteId, PrintStream ps) {
+        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 != 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);
@@ -180,8 +184,8 @@ public class BackupUtils {
                             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));
                             }
@@ -214,29 +218,29 @@ public class BackupUtils {
                 Log.e(TAG, e.toString());
             }
         }
-
+ 
         /**
          * 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;
             }
-
+ 
             PrintStream ps = getExportToTextPrintStream();
             if (ps == null) {
                 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,
                     "(" + 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 {
@@ -256,14 +260,14 @@ 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,
                     NoteColumns.TYPE + "=" + +Notes.TYPE_NOTE + " AND " + NoteColumns.PARENT_ID
                             + "=0", null, null);
-
+ 
             if (noteCursor != null) {
                 if (noteCursor.moveToFirst()) {
                     do {
@@ -278,14 +282,14 @@ public class BackupUtils {
                 noteCursor.close();
             }
             ps.close();
-
+ 
             return STATE_SUCCESS;
         }
-
+ 
         /**
          * Get a print stream pointed to the file {@generateExportedTextFile}
          */
-        private PrintStream getExportToTextPrintStream() {
+        private PrintStream getExportToTextPrintStream() {                  
             File file = generateFileMountedOnSDcard(mContext, R.string.file_path,
                     R.string.file_name_txt_format);
             if (file == null) {
@@ -297,7 +301,7 @@ public class BackupUtils {
             PrintStream ps = null;
             try {
                 FileOutputStream fos = new FileOutputStream(file);
-                ps = new PrintStream(fos);
+                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;
@@ -308,22 +312,22 @@ public class BackupUtils {
             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());
-        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();
             }
@@ -336,9 +340,8 @@ public class BackupUtils {
         } catch (IOException e) {
             e.printStackTrace();
         }
-
+// try catch 异常处理
         return null;
     }
 }
-
-
+ 

src/MiNotes-master/app/src/main/java/net/micode/notes/tool/DataUtils.java

@@ -35,9 +35,11 @@ import java.util.ArrayList;
 import java.util.HashSet;
 
 
+package net.micode.notes.tool;
+ 
 public class DataUtils {
     public static final String TAG = "DataUtils";
-    public static boolean batchDeleteNotes(ContentResolver resolver, HashSet<Long> ids) {
+    public static boolean batchDeleteNotes(ContentResolver resolver, HashSet<Long> ids) {   //直接删除多个笔记
         if (ids == null) {
             Log.d(TAG, "the ids is null");
             return true;
@@ -46,19 +48,20 @@ public class DataUtils {
             Log.d(TAG, "no id is in the hashset");
             return true;
         }
-
-        ArrayList<ContentProviderOperation> operationList = new ArrayList<ContentProviderOperation>();
+ 
+        ArrayList<ContentProviderOperation> operationList = new ArrayList<ContentProviderOperation>();  //提供一个任务列表
         for (long id : ids) {
             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());
+                    .newDelete(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id));  //用newDelete实现删除功能
+            operationList.add(builder.build());   //
         }
         try {
-            ContentProviderResult[] results = resolver.applyBatch(Notes.AUTHORITY, operationList);
+            ContentProviderResult[] results = resolver.applyBatch(Notes.AUTHORITY, operationList);//主机名（或叫Authority）用于唯一标识这个ContentProvider，外部调用者可以根据这个标识来找到它。
+            //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;
@@ -71,33 +74,33 @@ public class DataUtils {
         }
         return false;
     }
-
+ 
     public static void moveNoteToFoler(ContentResolver resolver, long id, long srcFolderId, long desFolderId) {
         ContentValues values = new ContentValues();
         values.put(NoteColumns.PARENT_ID, desFolderId);
         values.put(NoteColumns.ORIGIN_PARENT_ID, srcFolderId);
         values.put(NoteColumns.LOCAL_MODIFIED, 1);
-        resolver.update(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id), values, null, null);
+        resolver.update(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id), values, null, null);  //对需要移动的便签进行数据更新，然后用update实现
     }
-
+ 
     public static boolean batchMoveToFolder(ContentResolver resolver, HashSet<Long> ids,
             long folderId) {
         if (ids == null) {
             Log.d(TAG, "the ids is null");
             return true;
         }
-
+ 
         ArrayList<ContentProviderOperation> operationList = new ArrayList<ContentProviderOperation>();
         for (long id : ids) {
             ContentProviderOperation.Builder builder = ContentProviderOperation
-                    .newUpdate(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id));
+                    .newUpdate(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id));  //通过withAppendedId方法，为该Uri加上ID
             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);
+            ContentProviderResult[] results = resolver.applyBatch(Notes.AUTHORITY, operationList);  //applyBatch一次性处理一个操作列表
             if (results == null || results.length == 0 || results[0] == null) {
                 Log.d(TAG, "delete notes failed, ids:" + ids.toString());
                 return false;
@@ -110,7 +113,7 @@ public class DataUtils {
         }
         return false;
     }
-
+ 
     /**
      * Get the all folder count except system folders {@link Notes#TYPE_SYSTEM}}
      */
@@ -119,13 +122,13 @@ 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) {
             if(cursor.moveToFirst()) {
                 try {
-                    count = cursor.getInt(0);
+                    count = cursor.getInt(0);  
                 } catch (IndexOutOfBoundsException e) {
                     Log.e(TAG, "get folder count failed:" + e.toString());
                 } finally {
@@ -134,29 +137,29 @@ public class DataUtils {
             }
         }
         return count;
-    }
-
+    } 
+ 
     public static boolean visibleInNoteDatabase(ContentResolver resolver, long noteId, int type) {
-        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId),
+        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId), //通过withAppendedId方法，为该Uri加上ID
                 null,
                 NoteColumns.TYPE + "=? AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER,
-                new String [] {String.valueOf(type)},
-                null);
-
+                new String [] {String.valueOf(type)},   
+                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();
         }
         return exist;
     }
-
+ 
     public static boolean existInNoteDatabase(ContentResolver resolver, long noteId) {
         Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId),
                 null, null, null, null);
-
+ 
         boolean exist = false;
         if (cursor != null) {
             if (cursor.getCount() > 0) {
@@ -166,11 +169,11 @@ public class DataUtils {
         }
         return exist;
     }
-
+ 
     public static boolean existInDataDatabase(ContentResolver resolver, long dataId) {
         Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId),
                 null, null, null, null);
-
+ 
         boolean exist = false;
         if (cursor != null) {
             if (cursor.getCount() > 0) {
@@ -180,13 +183,14 @@ public class DataUtils {
         }
         return exist;
     }
-
+ 
     public static boolean checkVisibleFolderName(ContentResolver resolver, String name) {
         Cursor cursor = resolver.query(Notes.CONTENT_NOTE_URI, null,
                 NoteColumns.TYPE + "=" + Notes.TYPE_FOLDER +
                 " 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) {
@@ -196,14 +200,14 @@ public class DataUtils {
         }
         return exist;
     }
-
+ 
     public static HashSet<AppWidgetAttribute> getFolderNoteWidget(ContentResolver resolver, long folderId) {
         Cursor c = resolver.query(Notes.CONTENT_NOTE_URI,
                 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) {
             if (c.moveToFirst()) {
@@ -211,26 +215,26 @@ 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();
         }
         return set;
     }
-
+ 
     public static String getCallNumberByNoteId(ContentResolver resolver, long noteId) {
         Cursor cursor = resolver.query(Notes.CONTENT_DATA_URI,
                 new String [] { CallNote.PHONE_NUMBER },
                 CallNote.NOTE_ID + "=? AND " + CallNote.MIME_TYPE + "=?",
                 new String [] { String.valueOf(noteId), CallNote.CONTENT_ITEM_TYPE },
                 null);
-
+ 
         if (cursor != null && cursor.moveToFirst()) {
             try {
                 return cursor.getString(0);
@@ -242,7 +246,7 @@ public class DataUtils {
         }
         return "";
     }
-
+ 
     public static long getNoteIdByPhoneNumberAndCallDate(ContentResolver resolver, String phoneNumber, long callDate) {
         Cursor cursor = resolver.query(Notes.CONTENT_DATA_URI,
                 new String [] { CallNote.NOTE_ID },
@@ -250,11 +254,12 @@ 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 {
-                    return cursor.getLong(0);
+                    return cursor.getLong(0); //0对应的CallNote.NOTE_ID
                 } catch (IndexOutOfBoundsException e) {
                     Log.e(TAG, "Get call note id fails " + e.toString());
                 }
@@ -263,14 +268,14 @@ public class DataUtils {
         }
         return 0;
     }
-
+ 
     public static String getSnippetById(ContentResolver resolver, long noteId) {
         Cursor cursor = resolver.query(Notes.CONTENT_NOTE_URI,
                 new String [] { NoteColumns.SNIPPET },
                 NoteColumns.ID + "=?",
                 new String [] { String.valueOf(noteId)},
-                null);
-
+                null);//查询条件：noteId
+ 
         if (cursor != null) {
             String snippet = "";
             if (cursor.moveToFirst()) {
@@ -281,8 +286,7 @@ public class DataUtils {
         }
         throw new IllegalArgumentException("Note is not found with id: " + noteId);
     }
-
-    public static String getFormattedSnippet(String snippet) {
+    public static String getFormattedSnippet(String snippet) {  //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
         if (snippet != null) {
             snippet = snippet.trim();
             int index = snippet.indexOf('\n');
@@ -292,4 +296,5 @@ public class DataUtils {
         }
         return snippet;
     }
-}
+    
+}