add code comment

src/app/src/main/java/net/micode/notes/data/Contact.java

@@ -30,6 +30,7 @@ import java.util.HashMap;
  * */
 public class Contact {
     private static HashMap<String, String> sContactCache;
+    //用于记入日志的标识
     private static final String TAG = "Contact";
 
     //在数据库中的查询条件
@@ -49,7 +50,7 @@ public class Contact {
             sContactCache = new HashMap<String, String>();
         }
 
-        //如果包含电话号码，则返回电话号码
+        //如果找到电话号码，则返回电话号码对应的字符串
         if(sContactCache.containsKey(phoneNumber)) {
             return sContactCache.get(phoneNumber);
         }

src/app/src/main/java/net/micode/notes/data/Notes.java

@@ -17,15 +17,18 @@
 package net.micode.notes.data;
 
 import android.net.Uri;
+/*
+* 该类实现了对便签的建模，实现便签的一系列接口，定义便签参数
+* */
 public class Notes {
     public static final String AUTHORITY = "micode_notes";
-    //日志标识
+    //用于写入日志的标识，类名
     public static final String TAG = "Notes";
-    //便签类型标识
+    //用于标识便签类型-普通便签
     public static final int TYPE_NOTE     = 0;
-    //文件夹标识
+    //用于标识类型-文件夹
     public static final int TYPE_FOLDER   = 1;
-    //系统标识
+    //用于标识类型-系统文件
     public static final int TYPE_SYSTEM   = 2;
 
     /**
@@ -34,10 +37,10 @@ public class Notes {
      * {@link Notes#ID_TEMPARAY_FOLDER } is for notes belonging no folder
      * {@link Notes#ID_CALL_RECORD_FOLDER} is to store call records
      */
-    public static final int ID_ROOT_FOLDER = 0;//根文件夹
+    public static final int ID_ROOT_FOLDER = 0;//根文件夹标识
-    public static final int ID_TEMPARAY_FOLDER = -1;//临时文件夹
+    public static final int ID_TEMPARAY_FOLDER = -1;//临时文件夹标识
-    public static final int ID_CALL_RECORD_FOLDER = -2;//通话记录文件夹
+    public static final int ID_CALL_RECORD_FOLDER = -2;//通话记录文件夹标识
-    public static final int ID_TRASH_FOLER = -3;//垃圾文件夹
+    public static final int ID_TRASH_FOLER = -3;//垃圾文件夹标识
 
     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";
@@ -46,9 +49,9 @@ public class Notes {
     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_INVALIDE      = -1;//用于标识widget无效
-    public static final int TYPE_WIDGET_2X            = 0;
+    public static final int TYPE_WIDGET_2X            = 0;//用于标识使用的是2X大小的widget
-    public static final int TYPE_WIDGET_4X            = 1;
+    public static final int TYPE_WIDGET_4X            = 1;//用于标识使用的是4X大小的widget
 
     public static class DataConstants {
         public static final String NOTE = TextNote.CONTENT_ITEM_TYPE;
@@ -64,7 +67,7 @@ public class Notes {
     public static final Uri CONTENT_DATA_URI = Uri.parse("content://" + AUTHORITY + "/data");
 
     /**
-     *公用接口类
+     *该类定义了一系列接口，与便签数据表，存于数据库
      */
     public interface NoteColumns {
         /**

src/app/src/main/java/net/micode/notes/data/NotesDatabaseHelper.java

@@ -29,6 +29,7 @@ import net.micode.notes.data.Notes.NoteColumns;
 
 /**
  * 该类继承了SQLiteOpenHelper类，对SQLlite数据库进行操作
+ * 提供了便签访问数据库
  */
 public class NotesDatabaseHelper extends SQLiteOpenHelper {
     //数据库名称

src/app/src/main/java/net/micode/notes/data/NotesProvider.java

@@ -35,7 +35,7 @@ import net.micode.notes.data.Notes.NoteColumns;
 import net.micode.notes.data.NotesDatabaseHelper.TABLE;
 
 /**
- *定义便签提供者类
+ *定义便签提供者类，实现了在数据库中的便签的增删查改
  */
 public class NotesProvider extends ContentProvider {
     private static final UriMatcher mMatcher;