Update README.md

Author: woshimajintao

annotation_tool/ui/classification/README.md

@@ -1,41 +1,44 @@
 # 🏷️ Classification UI Module
 
-This directory contains the user interface components specifically designed for the **Whole-Video Classification** task.
+This directory contains the specific user interface components designed for the **Whole-Video Classification** task.
 
-In this mode, users assign attributes (labels) to an entire video clip rather than specific timestamps. The UI is designed to dynamically adapt to the project's JSON schema.
+Unlike the previous monolithic structure, this module is split into two specialized sub-packages (`event_editor` and `media_player`) that plug into the application's common workspace.
 
-## 📂 File Descriptions
+## 📂 Directory Structure & Modules
 
-### `panels.py`
+### 1. `event_editor/` (The Right Panel)
+**Responsible for:** Dynamic annotation forms, Schema management, and Task controls.
 
-This file defines the structural containers for the classification interface. It arranges the screen into three distinct areas:
+* **`editor.py`**:
+    * Defines **`ClassificationEventEditor`**: The main container for the right side of the screen.
+    * Hosts the **Undo/Redo** buttons specific to classification.
+    * Contains the **Schema Editor** (Add Head) and the **Manual Annotation Box** (Confirm/Clear).
+* **`dynamic_widgets.py`**:
+    * Contains the logic to programmatically generate UI elements based on the JSON schema:
+        * **`DynamicSingleLabelGroup`**: Generates Radio Buttons for mutually exclusive categories.
+        * **`DynamicMultiLabelGroup`**: Generates Checkboxes for multi-select categories.
+* **`__init__.py`**: Exposes `ClassificationEventEditor` for external use.
 
-* **`LeftPanel`**:
-    * Hosts the **Project Controls** (imported from `ui/common`).
-    * Displays the **Action Clip List** (File Tree).
-    * Manages filtering options (All / Done / Not Done).
-* **`CenterPanel`**:
-    * Contains the video player (`VideoViewAndControl`).
-    * Hosts navigation buttons (Previous/Next Action, Previous/Next Clip).
-* **`RightPanel`**:
-    * **Dynamic Form Area**: Automatically generates input fields based on the project Schema.
-    * **Manual Annotation Box**: Displays the current selection state and confirmation buttons.
+### 2. `media_player/` (The Center Panel)
+**Responsible for:** Video rendering, playback controls, and navigation.
 
-### `widgets.py`
-**Task-Specific Components**
-
-This file contains specialized widgets that are mostly generated programmatically based on the user's label definitions:
-
-* **`DynamicSingleLabelGroup`**: A `QGroupBox` containing **Radio Buttons**. Used when the schema defines a "single_label" type (Mutually exclusive).
-* **`DynamicMultiLabelGroup`**: A `QGroupBox` containing **Checkboxes**. Used when the schema defines a "multi_label" type (Multiple selections allowed).
-* **`VideoViewAndControl`**: A wrapper widget combining `QVideoWidget`, a custom clickable seek slider, and time labels specific to the classification workflow.
-
-### `__init__.py`
-* Exposes the classes from `panels` and `widgets` to the rest of the application, simplifying import statements.
+* **`preview.py`**:
+    * Defines **`MediaPreview`**: A wrapper around `QMediaPlayer` and `QVideoWidget`.
+    * Includes the custom **`ClickableSlider`** for instant seeking and time labels (e.g., `00:05 / 01:30`).
+* **`controls.py`**:
+    * Defines **`NavigationToolbar`**: Hosts the buttons for navigating between clips (Previous/Next Clip) and actions (Previous/Next Action).
+* **`__init__.py`**:
+    * Exposes **`ClassificationMediaPlayer`**: The assembled widget that combines the preview area and the navigation toolbar into a vertical layout.
 
 ---
 
-## 💡 Key Concepts
+## 🏗️ Architecture Changes
+
+### Where is `panels.py`?
+The specific `LeftPanel`, `CenterPanel`, and `RightPanel` classes have been refactored:
+1.  **Left Panel**: Now uses the generic **`CommonProjectTreePanel`** (located in `ui/common/clip_explorer.py`).
+2.  **Center & Right Panels**: Now reside in the `media_player` and `event_editor` folders described above.
+3.  **Assembly**: The overall layout is now handled by the **`UnifiedTaskPanel`** (in `ui/common/workspace.py`), which composes these components dynamically.
 
-1.  **Dynamic UI Generation**: The **RightPanel** does not have hardcoded buttons for labels (e.g., "Goal", "Foul"). Instead, it reads the `label_definitions` from the Model and instantiates the appropriate `Dynamic...LabelGroup` widgets from `widgets.py` at runtime.
-2.  **Shared Controls**: The **LeftPanel** embeds the `UnifiedProjectControls` from the `../common/` directory to ensure the "Save/Load/Export" experience is consistent with the Localization mode.
+### Dynamic UI Generation
+The **`event_editor`** module retains the core capability of adapting to the project's data model. It reads `label_definitions` from the Model and instantiates `Dynamic...LabelGroup` widgets at runtime, ensuring the tool works with any classification schema without code changes.