添加了Data包中的多处注释

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

@@ -25,46 +25,54 @@ import android.util.Log;
 
 import java.util.HashMap;
 
+/**
+ * 联系人
+ */
 public class Contact {
     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;

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

@@ -26,6 +26,7 @@ import android.net.Uri;
 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;
@@ -172,7 +173,7 @@ public class Notes {
          */
         public static final String VERSION = "version";
     }
-
+    // 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
@@ -245,7 +246,7 @@ public class Notes {
          * <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 {
         /**
@@ -261,7 +262,7 @@ public class Notes {
         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 {
         /**
@@ -281,5 +282,5 @@ public class Notes {
         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
 }

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

@@ -32,7 +32,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
 
     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";
@@ -61,7 +61,7 @@ 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 + "(" +
@@ -76,11 +76,11 @@ 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
@@ -92,7 +92,7 @@ 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
@@ -105,7 +105,7 @@ 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
@@ -117,7 +117,7 @@ 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
@@ -130,7 +130,7 @@ 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}
@@ -143,7 +143,7 @@ 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
@@ -156,7 +156,7 @@ 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
@@ -169,7 +169,7 @@ 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
@@ -180,7 +180,7 @@ 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
@@ -191,7 +191,7 @@ 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
@@ -204,18 +204,18 @@ 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");
-    }
+    }//构造函数，传入数据库的名称和版本
 
     private void reCreateNoteTableTriggers(SQLiteDatabase db) {
         db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_update");
@@ -233,7 +233,8 @@ 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();
@@ -268,14 +269,14 @@ 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");
@@ -285,20 +286,22 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         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) {
@@ -331,7 +334,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
             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);

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

@@ -34,8 +34,17 @@ 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
+ * update：更新
+ * 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;
@@ -51,7 +60,9 @@ public class NotesProvider extends ContentProvider {
     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);
+        // 创建UriMatcher时，调用UriMatcher(UriMatcher.NO_MATCH)表示不匹配任何路径的返回码
         mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE);
         mMatcher.addURI(Notes.AUTHORITY, "note/#", URI_NOTE_ITEM);
         mMatcher.addURI(Notes.AUTHORITY, "data", URI_DATA);
@@ -80,18 +91,24 @@ public class NotesProvider extends ContentProvider {
             + " 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);
@@ -113,6 +130,7 @@ 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");
                 }
@@ -120,6 +138,8 @@ public class NotesProvider extends ContentProvider {
                 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 {
@@ -139,6 +159,7 @@ public class NotesProvider extends ContentProvider {
                 }
                 break;
             default:
+                //抛出异常
                 throw new IllegalArgumentException("Unknown URI " + uri);
         }
         if (c != null) {
@@ -148,7 +169,9 @@ public class NotesProvider extends ContentProvider {
     }
 
     @Override
+    // 插入一个uri
     public Uri insert(Uri uri, ContentValues values) {
+        // 插入一个uri
         SQLiteDatabase db = mHelper.getWritableDatabase();
         long dataId = 0, noteId = 0, insertedId = 0;
         switch (mMatcher.match(uri)) {
@@ -183,8 +206,10 @@ public class NotesProvider extends ContentProvider {
 
     @Override
     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)) {
@@ -266,11 +291,11 @@ 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 ");
@@ -292,7 +317,7 @@ 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());
     }