无法使用 CMake 构建 Qt-Widgets 应用程序

Question

我正在尝试设置一个构建 Qt-Widgets 应用程序的 CMake 项目，但无法正确编译它。 我的项目结构如下：

• 包括/
  • 主窗口.hpp
• 资源/
  • 主窗口.ui
• 源/
  • 主文件
  • 主窗口.cpp
• CMakeLists.txt

CMakeLists.txt

cmake_minimum_required(VERSION 3.10)
find_package(Qt5 COMPONENTS Widgets REQUIRED)

project(Test VERSION 0.1 LANGUAGES CXX)

set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
set(CMAKE_AUTOUIC ON)
set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTOUIC_SEARCH_PATHS resources)

add_executable(App src/mainwindow.cpp src/main.cpp resources/mainwindow.ui)
target_include_directories(App PRIVATE include)
target_link_libraries(App PRIVATE Qt5::Widgets)

主窗口.hpp

#ifndef MAINWINDOW_HPP_
#define MAINWINDOW_HPP_

#include <QMainWindow>

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class Test : public QMainWindow {
    Q_OBJECT

public:
    Test(QWidget *parent = nullptr);
    ~Test();

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_HPP_

主窗口.cpp

#include "mainwindow.hpp"
#include "ui_mainwindow.h"

Test::Test(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindow){
    ui->setupUi(this);
}

Test::~Test(){
    delete ui;
}

主文件

#include "mainwindow.hpp"
#include <QApplication>


int main(int argc, char *argv[]){
    QApplication a(argc, argv);
    Test w;
    w.show();
    return a.exec();
}

---

当我尝试构建项目时：

cmake -Bbuild -DCMAKE_BUILD_TYPE=Debug
cmake --build build --target all

我收到以下链接器错误：

[ 20%] Automatic MOC and UIC for target App
[ 20%] Built target App_autogen
[ 40%] Building CXX object CMakeFiles/App.dir/App_autogen/mocs_compilation.cpp.o
[ 60%] Building CXX object CMakeFiles/App.dir/src/mainwindow.cpp.o
[ 80%] Building CXX object CMakeFiles/App.dir/src/main.cpp.o
[100%] Linking CXX executable App
/usr/bin/ld: CMakeFiles/App.dir/src/mainwindow.cpp.o: in function `Test::Test(QWidget*)': .../src/mainwindow.cpp:4: undefined reference to `vtable for Test'
/usr/bin/ld: .../src/mainwindow.cpp:4: undefined reference to `vtable for Test'
/usr/bin/ld: CMakeFiles/App.dir/src/mainwindow.cpp.o: in function `Test::~Test()': .../src/mainwindow.cpp:8: undefined reference to `vtable for Test'
/usr/bin/ld: .../src/mainwindow.cpp:8: undefined reference to `vtable for Test'
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/App.dir/build.make:132: App] Error 1
make[1]: *** [CMakeFiles/Makefile2:84: CMakeFiles/App.dir/all] Error 2
make: *** [Makefile:91: all] Error 2

查看 cmakes 生成的link.txt ，似乎所需的目标文件已正确链接

/usr/bin/c++ \
    -g CMakeFiles/App.dir/App_autogen/mocs_compilation.cpp.o \
       CMakeFiles/App.dir/src/mainwindow.cpp.o \
       CMakeFiles/App.dir/src/main.cpp.o \
    -o App \
       /usr/lib/libQt5Widgets.so.5.15.4 \
       /usr/lib/libQt5Gui.so.5.15.4 \
       /usr/lib/libQt5Core.so.5.15.4 

我不太确定，为什么 vtable 引用未定义。 我在这里做错了什么？

Answer 1

解决方案是将include/mainwindow.hpp添加到源中。

add_executable(App src/mainwindow.cpp src/main.cpp include/mainwindow.hpp resources/mainwindow.ui)

生成的ui_mainwindow.h似乎需要这才能查看 MainWindow 类的 vtable 条目。