Update NotesProvider.java

源程序代码-小米便签-Notes-master/Notes-master/src/net/micode/notes/data/NotesProvider.java

@@ -34,7 +34,10 @@ import net.micode.notes.data.Notes.DataColumns;
 import net.micode.notes.data.Notes.NoteColumns;
 import net.micode.notes.data.NotesDatabaseHelper.TABLE;
 
-
+/**
+ * NotesProvider 是小米便签应用的内容提供者，负责管理便签数据的访问。
+ * 它实现了对便签和便签数据的CRUD操作，并支持搜索功能。
+ */
 public class NotesProvider extends ContentProvider {
     private static final UriMatcher mMatcher;
 
@@ -42,15 +45,16 @@ public class NotesProvider extends ContentProvider {
 
     private static final String TAG = "NotesProvider";
 
-    private static final int URI_NOTE            = 1;
+    private static final int URI_NOTE            = 1;   // 匹配所有便签
-    private static final int URI_NOTE_ITEM       = 2;
+    private static final int URI_NOTE_ITEM       = 2;   // 匹配单个便签
-    private static final int URI_DATA            = 3;
+    private static final int URI_DATA            = 3;  // 匹配所有便签数据
-    private static final int URI_DATA_ITEM       = 4;
+    private static final int URI_DATA_ITEM       = 4;  // 匹配单个便签数据
 
-    private static final int URI_SEARCH          = 5;
+    private static final int URI_SEARCH          = 5;   // 匹配搜索请求
-    private static final int URI_SEARCH_SUGGEST  = 6;
+    private static final int URI_SEARCH_SUGGEST  = 6;   // 匹配搜索建议请求
 
     static {
+      	// 初始化URI匹配器，用于识别不同的URI请求
         mMatcher = new UriMatcher(UriMatcher.NO_MATCH);
         mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE);
         mMatcher.addURI(Notes.AUTHORITY, "note/#", URI_NOTE_ITEM);
@@ -72,19 +76,31 @@ 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;
-
+	// 便签搜索查询语句，用于搜索便签摘要中包含特定关键词的便签
     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;
-
+	    /**
+     * 初始化ContentProvider，创建数据库帮助类实例
+     * @return 初始化成功返回true，否则返回false
+     */
     @Override
     public boolean onCreate() {
         mHelper = NotesDatabaseHelper.getInstance(getContext());
         return true;
     }
 
+    /**
+     * 查询便签数据
+     * @param uri 查询的URI
+     * @param projection 返回的列
+     * @param selection 选择条件
+     * @param selectionArgs 选择条件参数
+     * @param sortOrder 排序方式
+     * @return 返回符合条件的Cursor
+     */
     @Override
     public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
             String sortOrder) {
@@ -93,25 +109,30 @@ public class NotesProvider extends ContentProvider {
         String id = null;
         switch (mMatcher.match(uri)) {
             case URI_NOTE:
+             // 查询所有便签
                 c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null,
                         sortOrder);
                 break;
             case URI_NOTE_ITEM:
+            // 查询单个便签
                 id = uri.getPathSegments().get(1);
                 c = db.query(TABLE.NOTE, projection, NoteColumns.ID + "=" + id
                         + parseSelection(selection), selectionArgs, null, null, sortOrder);
                 break;
             case URI_DATA:
+            // 查询所有便签数据
                 c = db.query(TABLE.DATA, projection, selection, selectionArgs, null, null,
                         sortOrder);
                 break;
             case URI_DATA_ITEM:
+             // 查询单个便签数据
                 id = uri.getPathSegments().get(1);
                 c = db.query(TABLE.DATA, projection, DataColumns.ID + "=" + id
                         + parseSelection(selection), selectionArgs, null, null, sortOrder);
                 break;
             case URI_SEARCH:
             case URI_SEARCH_SUGGEST:
+            // 处理搜索请求
                 if (sortOrder != null || projection != null) {
                     throw new IllegalArgumentException(
                             "do not specify sortOrder, selection, selectionArgs, or projection" + "with this query");
@@ -131,6 +152,7 @@ public class NotesProvider extends ContentProvider {
                 }
 
                 try {
+                  // 执行搜索查询
                     searchString = String.format("%%%s%%", searchString);
                     c = db.rawQuery(NOTES_SNIPPET_SEARCH_QUERY,
                             new String[] { searchString });
@@ -141,21 +163,29 @@ public class NotesProvider extends ContentProvider {
             default:
                 throw new IllegalArgumentException("Unknown URI " + uri);
         }
+// 设置通知URI，当数据变化时通知观察者
         if (c != null) {
             c.setNotificationUri(getContext().getContentResolver(), uri);
         }
         return c;
     }
-
+    /**
+     * 插入新的便签或便签数据
+     * @param uri 插入的URI
+     * @param values 要插入的数据
+     * @return 返回插入后的URI
+     */
     @Override
     public Uri insert(Uri uri, ContentValues values) {
         SQLiteDatabase db = mHelper.getWritableDatabase();
         long dataId = 0, noteId = 0, insertedId = 0;
         switch (mMatcher.match(uri)) {
             case URI_NOTE:
+            // 插入新便签
                 insertedId = noteId = db.insert(TABLE.NOTE, null, values);
                 break;
             case URI_DATA:
+            // 插入新便签数据
                 if (values.containsKey(DataColumns.NOTE_ID)) {
                     noteId = values.getAsLong(DataColumns.NOTE_ID);
                 } else {
@@ -181,6 +211,13 @@ public class NotesProvider extends ContentProvider {
         return ContentUris.withAppendedId(uri, insertedId);
     }
 
+    /**
+     * 删除便签或便签数据
+     * @param uri 删除的URI
+     * @param selection 选择条件
+     * @param selectionArgs 选择条件参数
+     * @return 返回删除的行数
+     */
     @Override
     public int delete(Uri uri, String selection, String[] selectionArgs) {
         int count = 0;
@@ -189,10 +226,12 @@ public class NotesProvider extends ContentProvider {
         boolean deleteData = false;
         switch (mMatcher.match(uri)) {
             case URI_NOTE:
+            // 删除便签
                 selection = "(" + selection + ") AND " + NoteColumns.ID + ">0 ";
                 count = db.delete(TABLE.NOTE, selection, selectionArgs);
                 break;
             case URI_NOTE_ITEM:
+            // 删除单个便签
                 id = uri.getPathSegments().get(1);
                 /**
                  * ID that smaller than 0 is system folder which is not allowed to
@@ -206,10 +245,12 @@ public class NotesProvider extends ContentProvider {
                         NoteColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
                 break;
             case URI_DATA:
+             // 删除便签数据
                 count = db.delete(TABLE.DATA, selection, selectionArgs);
                 deleteData = true;
                 break;
             case URI_DATA_ITEM:
+             // 删除单个便签数据
                 id = uri.getPathSegments().get(1);
                 count = db.delete(TABLE.DATA,
                         DataColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
@@ -218,6 +259,7 @@ public class NotesProvider extends ContentProvider {
             default:
                 throw new IllegalArgumentException("Unknown URI " + uri);
         }
+      // 通知数据变化
         if (count > 0) {
             if (deleteData) {
                 getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
@@ -226,7 +268,14 @@ public class NotesProvider extends ContentProvider {
         }
         return count;
     }
-
+    /**
+     * 更新便签或便签数据
+     * @param uri 更新的URI
+     * @param values 要更新的数据
+     * @param selection 选择条件
+     * @param selectionArgs 选择条件参数
+     * @return 返回更新的行数
+     */
     @Override
     public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
         int count = 0;
@@ -235,20 +284,24 @@ public class NotesProvider extends ContentProvider {
         boolean updateData = false;
         switch (mMatcher.match(uri)) {
             case URI_NOTE:
+            // 更新便签
                 increaseNoteVersion(-1, selection, selectionArgs);
                 count = db.update(TABLE.NOTE, values, selection, selectionArgs);
                 break;
             case URI_NOTE_ITEM:
+            // 更新单个便签
                 id = uri.getPathSegments().get(1);
                 increaseNoteVersion(Long.valueOf(id), selection, selectionArgs);
                 count = db.update(TABLE.NOTE, values, NoteColumns.ID + "=" + id
                         + parseSelection(selection), selectionArgs);
                 break;
             case URI_DATA:
+            // 更新便签数据
                 count = db.update(TABLE.DATA, values, selection, selectionArgs);
                 updateData = true;
                 break;
             case URI_DATA_ITEM:
+            // 更新单个便签数据
                 id = uri.getPathSegments().get(1);
                 count = db.update(TABLE.DATA, values, DataColumns.ID + "=" + id
                         + parseSelection(selection), selectionArgs);
@@ -257,7 +310,7 @@ public class NotesProvider extends ContentProvider {
             default:
                 throw new IllegalArgumentException("Unknown URI " + uri);
         }
-
+	// 通知数据变化
         if (count > 0) {
             if (updateData) {
                 getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
@@ -266,11 +319,20 @@ public class NotesProvider extends ContentProvider {
         }
         return count;
     }
-
+    /**
+     * 解析选择条件，添加额外的条件
+     * @param selection 原始选择条件
+     * @return 解析后的选择条件
+     */
     private String parseSelection(String selection) {
         return (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : "");
     }
-
+    /**
+     * 增加便签版本号，用于数据同步
+     * @param id 便签ID，如果为-1则更新所有符合条件的便签
+     * @param selection 选择条件
+     * @param selectionArgs 选择条件参数
+     */
     private void increaseNoteVersion(long id, String selection, String[] selectionArgs) {
         StringBuilder sql = new StringBuilder(120);
         sql.append("UPDATE ");
@@ -296,6 +358,11 @@ public class NotesProvider extends ContentProvider {
         mHelper.getWritableDatabase().execSQL(sql.toString());
     }
 
+    /**
+     * 获取URI对应的MIME类型
+     * @param uri 请求的URI
+     * @return 返回对应的MIME类型
+     */
     @Override
     public String getType(Uri uri) {
         // TODO Auto-generated method stub