mainwindow_showcase 教学示例：补 Designer 双版本表单（mainwindow2）+ 表单维护

- 新增 mainwindow2.{h,cpp,ui}：用 Qt Designer 生成的第二套 QMainWindow 表单
  （File/Edit/Help 菜单 + actionOpen/actionAbout_Me），供课堂对比「代码搭界面」
  与「Designer 拖界面」两条路线。
- 新增子目录 CMakeLists.txt：供单独打开该示例构建（顶层 add_subdirectory 不递归，
  与 lineedit_eye_toggle / mandelbrot_renderer 同模式）。
- mainwindow.ui / mainwindow.qrc：经 Designer 重新保存后的表单与资源清单维护
  （iconset 去掉 resource= 显式引用、属性顺序由 Designer 重排）。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/teaching/examples/mainwindow_showcase/CMakeLists.txt

@@ -0,0 +1,51 @@
+cmake_minimum_required(VERSION 3.5)
+
+project(qt_mainwindow_showcase LANGUAGES CXX)
+
+set(CMAKE_INCLUDE_CURRENT_DIR ON)
+
+set(CMAKE_AUTOUIC ON)
+set(CMAKE_AUTOMOC ON)
+set(CMAKE_AUTORCC ON)
+
+set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+# QtCreator supports the following variables for Android, which are identical to qmake Android variables.
+# Check http://doc.qt.io/qt-5/deployment-android.html for more information.
+# They need to be set before the find_package(Qt5 ...) call.
+
+#if(ANDROID)
+#    set(ANDROID_PACKAGE_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/android")
+#    if (ANDROID_ABI STREQUAL "armeabi-v7a")
+#        set(ANDROID_EXTRA_LIBS
+#            ${CMAKE_CURRENT_SOURCE_DIR}/path/to/libcrypto.so
+#            ${CMAKE_CURRENT_SOURCE_DIR}/path/to/libssl.so)
+#    endif()
+#endif()
+
+find_package(Qt5 COMPONENTS Widgets REQUIRED)
+
+if(ANDROID)
+  add_library(qt_mainwindow_showcase
+    main.cpp
+    mainwindow_showcase.cpp
+    mainwindow_showcase.h
+    mainwindow2.cpp
+    mainwindow2.h
+    mainwindow2.ui
+    mainwindow.ui
+  )
+else()
+add_executable(qt_mainwindow_showcase
+    main.cpp
+    mainwindow_showcase.cpp
+    mainwindow_showcase.h
+    mainwindow2.cpp
+    mainwindow2.h
+    mainwindow2.ui
+    mainwindow.ui
+    mainwindow.qrc)
+endif()
+
+target_link_libraries(qt_mainwindow_showcase PRIVATE Qt5::Widgets)

docs/teaching/examples/mainwindow_showcase/mainwindow.qrc

@@ -6,4 +6,8 @@
         <file>icons/about.png</file>
         <file>icons/dock.png</file>
     </qresource>
+    <qresource prefix="/new/prefix1">
+        <file>icons/about.png</file>
+    </qresource>
+    <qresource prefix="/new/prefix2"/>
 </RCC>

docs/teaching/examples/mainwindow_showcase/mainwindow.ui

@@ -14,10 +14,9 @@
    <string>QMainWindow 教学综合示例</string>
   </property>
   <property name="windowIcon">
-   <iconset resource="mainwindow.qrc">
+   <iconset>
     <normaloff>:/icons/app.png</normaloff>:/icons/app.png</iconset>
   </property>
-  <!-- 5.5 中心部件：QTextEdit（编辑器主体） -->
   <widget class="QWidget" name="centralwidget">
    <layout class="QVBoxLayout" name="centralLayout">
     <property name="spacing">
@@ -46,14 +45,13 @@
     </item>
    </layout>
   </widget>
-  <!-- 5.1 菜单栏：文件 / 视图 / 帮助 -->
   <widget class="QMenuBar" name="menubar">
    <property name="geometry">
     <rect>
      <x>0</x>
      <y>0</y>
      <width>720</width>
-     <height>22</height>
+     <height>21</height>
     </rect>
    </property>
    <widget class="QMenu" name="menuFile">
@@ -95,9 +93,7 @@
    <addaction name="menuView"/>
    <addaction name="menuHelp"/>
   </widget>
-  <!-- 5.3 状态栏（.ui 占位，永久标签在 .cpp 用 addPermanentWidget 添加） -->
   <widget class="QStatusBar" name="statusbar"/>
-  <!-- 5.2 工具栏：复用同一批 QAction（QAction 是菜单项与工具按钮的公共抽象） -->
   <widget class="QToolBar" name="mainToolBar">
    <property name="windowTitle">
     <string>主工具栏</string>
@@ -113,7 +109,6 @@
    <addaction name="actionToggleDockFloating"/>
    <addaction name="actionAbout"/>
   </widget>
-  <!-- 5.4 铆接部件（浮动窗口）：可拖出浮动、停靠到边缘 -->
   <widget class="QDockWidget" name="dockWidget">
    <property name="windowTitle">
     <string>浮动窗口</string>
@@ -138,36 +133,35 @@
     </layout>
    </widget>
   </widget>
-  <!-- 5.1 QAction：菜单项与工具按钮的公共抽象。图标取自 5.6 资源文件 -->
   <action name="actionNew">
    <property name="icon">
-    <iconset resource="mainwindow.qrc">
+    <iconset>
      <normaloff>:/icons/new.png</normaloff>:/icons/new.png</iconset>
    </property>
    <property name="text">
     <string>新建</string>
    </property>
-   <property name="shortcut">
-    <string>Ctrl+N</string>
-   </property>
    <property name="statusTip">
     <string>清空编辑区（5.5 中心部件）</string>
    </property>
+   <property name="shortcut">
+    <string>Ctrl+N</string>
+   </property>
   </action>
   <action name="actionQuit">
    <property name="icon">
-    <iconset resource="mainwindow.qrc">
+    <iconset>
      <normaloff>:/icons/quit.png</normaloff>:/icons/quit.png</iconset>
    </property>
    <property name="text">
     <string>退出</string>
    </property>
-   <property name="shortcut">
-    <string>Ctrl+Q</string>
-   </property>
    <property name="statusTip">
     <string>退出程序</string>
    </property>
+   <property name="shortcut">
+    <string>Ctrl+Q</string>
+   </property>
   </action>
   <action name="actionToggleToolBar">
    <property name="checkable">
@@ -213,7 +207,7 @@
   </action>
   <action name="actionToggleDockFloating">
    <property name="icon">
-    <iconset resource="mainwindow.qrc">
+    <iconset>
      <normaloff>:/icons/dock.png</normaloff>:/icons/dock.png</iconset>
    </property>
    <property name="text">
@@ -281,7 +275,7 @@
   </action>
   <action name="actionAbout">
    <property name="icon">
-    <iconset resource="mainwindow.qrc">
+    <iconset>
      <normaloff>:/icons/about.png</normaloff>:/icons/about.png</iconset>
    </property>
    <property name="text">
@@ -292,8 +286,6 @@
    </property>
   </action>
  </widget>
- <resources>
+ <resources/>
-  <include location="mainwindow.qrc"/>
- </resources>
  <connections/>
 </ui>

docs/teaching/examples/mainwindow_showcase/mainwindow2.cpp

@@ -0,0 +1,14 @@
+#include "mainwindow2.h"
+#include "ui_mainwindow2.h"
+
+MainWindow2::MainWindow2(QWidget *parent) :
+    QMainWindow(parent),
+    ui(new Ui::MainWindow2)
+{
+    ui->setupUi(this);
+}
+
+MainWindow2::~MainWindow2()
+{
+    delete ui;
+}

docs/teaching/examples/mainwindow_showcase/mainwindow2.h

@@ -0,0 +1,22 @@
+#ifndef MAINWINDOW2_H
+#define MAINWINDOW2_H
+
+#include <QMainWindow>
+
+namespace Ui {
+class MainWindow2;
+}
+
+class MainWindow2 : public QMainWindow
+{
+    Q_OBJECT
+
+public:
+    explicit MainWindow2(QWidget *parent = nullptr);
+    ~MainWindow2();
+
+private:
+    Ui::MainWindow2 *ui;
+};
+
+#endif // MAINWINDOW2_H

docs/teaching/examples/mainwindow_showcase/mainwindow2.ui

@@ -0,0 +1,66 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>MainWindow2</class>
+ <widget class="QMainWindow" name="MainWindow2">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>640</width>
+    <height>480</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>MainWindow</string>
+  </property>
+  <widget class="QWidget" name="centralwidget"/>
+  <widget class="QMenuBar" name="menubar">
+   <property name="geometry">
+    <rect>
+     <x>0</x>
+     <y>0</y>
+     <width>640</width>
+     <height>21</height>
+    </rect>
+   </property>
+   <widget class="QMenu" name="menuFile">
+    <property name="title">
+     <string>&amp;File</string>
+    </property>
+    <addaction name="actionOpen"/>
+   </widget>
+   <widget class="QMenu" name="menuEdit">
+    <property name="title">
+     <string>Edit</string>
+    </property>
+    <addaction name="actionOpen"/>
+   </widget>
+   <widget class="QMenu" name="menuAbout">
+    <property name="title">
+     <string>Help</string>
+    </property>
+    <addaction name="actionOpen"/>
+    <addaction name="actionAbout_Me"/>
+   </widget>
+   <addaction name="menuFile"/>
+   <addaction name="menuEdit"/>
+   <addaction name="menuAbout"/>
+  </widget>
+  <widget class="QStatusBar" name="statusbar"/>
+  <action name="actionOpen">
+   <property name="text">
+    <string>&amp;Open</string>
+   </property>
+   <property name="shortcut">
+    <string>Alt+O</string>
+   </property>
+  </action>
+  <action name="actionAbout_Me">
+   <property name="text">
+    <string>About Me</string>
+   </property>
+  </action>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>