新增了文件夹嵌套的功能

src/main/java/net/micode/notes/tool/DataUtils.java

@@ -272,11 +272,27 @@ public class DataUtils {
      * @return 存在返回true，否则返回false
      */
     public static boolean checkVisibleFolderName(ContentResolver resolver, String name) {
+        return checkVisibleFolderName(resolver, name, Notes.ID_ROOT_FOLDER);
+    }
+    
+    /**
+     * 检查可见文件夹名称是否存在（重载方法，支持指定父文件夹ID）
+     * <p>
+     * 检查指定名称的文件夹是否存在于指定父文件夹下，且不在垃圾箱中。
+     * </p>
+     * 
+     * @param resolver ContentResolver实例，用于与内容提供者交互
+     * @param name 文件夹名称
+     * @param parentId 父文件夹ID
+     * @return 存在返回true，否则返回false
+     */
+    public static boolean checkVisibleFolderName(ContentResolver resolver, String name, long parentId) {
         Cursor cursor = resolver.query(Notes.CONTENT_NOTE_URI, null,
                 NoteColumns.TYPE + "=" + Notes.TYPE_FOLDER +
                 " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER +
+                " AND " + NoteColumns.PARENT_ID + "=?" +
                 " AND " + NoteColumns.SNIPPET + "=?",
-                new String[] { name }, null);
+                new String[] { String.valueOf(parentId), name }, null);
         boolean exist = false;
         if(cursor != null) {
             if(cursor.getCount() > 0) {

src/main/java/net/micode/notes/ui/NotesListActivity.java

@@ -201,7 +201,7 @@ public class NotesListActivity extends Activity implements OnClickListener, OnIt
          * Insert an introduction when user firstly use this application
          */
         setAppInfoFromRawRes();
-        
+
         // 注册Android 13+的返回键回调
         if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.TIRAMISU) {
             getOnBackInvokedDispatcher().registerOnBackInvokedCallback(
@@ -1002,7 +1002,7 @@ public class NotesListActivity extends Activity implements OnClickListener, OnIt
             public void onClick(View v) {
                 hideSoftInput(etName);
                 String name = etName.getText().toString();
-                if (DataUtils.checkVisibleFolderName(mContentResolver, name)) {
+                if (DataUtils.checkVisibleFolderName(mContentResolver, name, mCurrentFolderId)) {
                     Toast.makeText(NotesListActivity.this, getString(R.string.folder_exist, name),
                             Toast.LENGTH_LONG).show();
                     etName.setSelection(0, etName.length());
@@ -1023,6 +1023,7 @@ public class NotesListActivity extends Activity implements OnClickListener, OnIt
                     ContentValues values = new ContentValues();
                     values.put(NoteColumns.SNIPPET, name);
                     values.put(NoteColumns.TYPE, Notes.TYPE_FOLDER);
+                    values.put(NoteColumns.PARENT_ID, mCurrentFolderId);
                     mContentResolver.insert(Notes.CONTENT_NOTE_URI, values);
                 }
                 dialog.dismiss();
@@ -1068,10 +1069,32 @@ public class NotesListActivity extends Activity implements OnClickListener, OnIt
     private void handleBackPress() {
         switch (mState) {
             case SUB_FOLDER:
-                mCurrentFolderId = Notes.ID_ROOT_FOLDER;
-                mState = ListEditState.NOTE_LIST;
-                startAsyncNotesListQuery();
-                mTitleBar.setVisibility(View.GONE);
+                // 查询当前文件夹的父文件夹ID
+                Cursor cursor = mContentResolver.query(Notes.CONTENT_NOTE_URI,
+                        new String[]{NoteColumns.PARENT_ID, NoteColumns.SNIPPET},
+                        NoteColumns.ID + "=?",
+                        new String[]{String.valueOf(mCurrentFolderId)},
+                        null);
+                
+                if (cursor != null && cursor.moveToFirst()) {
+                    long parentId = cursor.getLong(0);
+                    String parentName = cursor.getString(1);
+                    cursor.close();
+                    
+                    if (parentId == Notes.ID_ROOT_FOLDER) {
+                        // 如果父文件夹是根文件夹，返回根目录
+                        mCurrentFolderId = Notes.ID_ROOT_FOLDER;
+                        mState = ListEditState.NOTE_LIST;
+                        mTitleBar.setVisibility(View.GONE);
+                    } else {
+                        // 否则返回上一级文件夹
+                        mCurrentFolderId = parentId;
+                        mState = ListEditState.SUB_FOLDER;
+                        mTitleBar.setText(parentName);
+                        mTitleBar.setVisibility(View.VISIBLE);
+                    }
+                    startAsyncNotesListQuery();
+                }
                 break;
             case CALL_RECORD_FOLDER:
                 mCurrentFolderId = Notes.ID_ROOT_FOLDER;
@@ -1402,13 +1425,21 @@ public class NotesListActivity extends Activity implements OnClickListener, OnIt
                         }
                         break;
                     case SUB_FOLDER:
-                    case CALL_RECORD_FOLDER:
                         if (item.getType() == Notes.TYPE_NOTE) {
                             openNode(item);
+                        } else if (item.getType() == Notes.TYPE_FOLDER) {
+                            openFolder(item);
                         } else {
                             Log.e(TAG, "Wrong note type in SUB_FOLDER");
                         }
                         break;
+                    case CALL_RECORD_FOLDER:
+                        if (item.getType() == Notes.TYPE_NOTE) {
+                            openNode(item);
+                        } else {
+                            Log.e(TAG, "Wrong note type in CALL_RECORD_FOLDER");
+                        }
+                        break;
                     default:
                         break;
                 }

src/main/res/menu/sub_folder.xml

@@ -18,6 +18,9 @@
 <menu
     xmlns:android="http://schemas.android.com/apk/res/android">
 
+    <item
+        android:id="@+id/menu_new_folder"
+        android:title="@string/menu_create_folder"/>
     <item
         android:id="@+id/menu_new_note"
         android:title="@string/notelist_menu_new"/>