使用 CMake 检测 Qt5

Question

我正在尝试在Ubuntu上安装和使用Qt 5。为我的需要Qt 5的项目运行CMake会导致：

-- The C compiler identification is GNU 4.8.4
-- The CXX compiler identification is GNU 4.8.4
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
CMake Warning at /usr/local/share/cmake-3.2/Modules/FindQt4.cmake:626 (message):
  /usr/bin/qmake reported QT_INSTALL_LIBS as "/usr/lib/x86_64-linux-gnu" but
  QtCore could not be found there.  Qt is NOT installed correctly for the
  target build environment.

我尝试了来自

https://askubuntu.com/questions/508503/whats-the-development-package-for-qt5-in-14-04

https://www.kdab.com/using-cmake-with-qt-5/

如何查找和使用 Qt 5 和 CMake？

Answer 1

查看 Qt 5 文档，其中包含有关如何使用 CMake 的部分： http://doc.qt.io/qt-5/cmake-manual.html

它提供了一个示例：

cmake_minimum_required(VERSION 2.8.11)
project(testproject)
# Find includes in corresponding build directories
set(CMAKE_INCLUDE_CURRENT_DIR ON)
# Instruct CMake to run moc automatically when needed.
set(CMAKE_AUTOMOC ON)
# Find the QtWidgets library
find_package(Qt5Widgets)
# Tell CMake to create the helloworld executable
add_executable(helloworld WIN32 main.cpp)
# Use the Widgets module from Qt 5.
target_link_libraries(helloworld Qt5::Widgets)

请注意包含与您的行不同的find_package的行。它还包含建议，如何帮助CMake找到您的Qt安装：

为了使find_package成功，必须在下面找到Qt 5 必须在 CMake 中设置CMAKE_PREFIX_PATH或Qt5_DIR 缓存到 Qt5WidgetsConfig.cmake 文件的位置。最简单的 使用 CMake 的方法是设置CMAKE_PREFIX_PATH环境变量 到 Qt 5 的安装前缀。

延伸阅读：CMake：以正确的方式找到Qt5

Answer 2

我按照 usr1234567 的建议添加了正确的"CMAKE_PREFIX_PATH"（不应该由安装程序制作吗？添加了以下包含目录https://www.kdab.com/using-cmake-with-qt-5/（它是否应该包含在手册 http://doc.qt.io/qt-5/cmake-manual.html 和 KDevelop 生成的 CMakeList 中.txt ？），此外，生成 GUI 元素的源文件（将 #include 目录从QtGui改为QtWidgets后，不应该由KDevelop制作吗？我将CMakeLists.txt转换为显示的内容。也许不是最佳的，但有效。（这是我第一次尝试Qt，我想提到的困难会阻止那些喜欢开箱即用的解决方案的人）

cmake_minimum_required(VERSION 2.8.11)
project(MyFirst)
# Find includes in corresponding build directories
set(CMAKE_INCLUDE_CURRENT_DIR ON)
# Instruct CMake to run moc automatically when needed.
set(CMAKE_AUTOMOC ON)
# Find the QtWidgets library
find_package(Qt5Widgets)
# Tell CMake to create the helloworld executable
add_executable(MyFirst main.cpp MyFirst.cpp)
# The Qt5Widgets_INCLUDES also includes the include directories for
  # dependencies QtCore and QtGui
  include_directories(${Qt5Widgets_INCLUDES})
  # We need add -DQT_WIDGETS_LIB when using QtWidgets in Qt 5.
  add_definitions(${Qt5Widgets_DEFINITIONS})
  # Executables fail to build with Qt 5 in the default configuration
  # without -fPIE. We add that here.
  set(CMAKE_CXX_FLAGS "${Qt5Widgets_EXECUTABLE_COMPILE_FLAGS}")
# Use the Widgets module from Qt 5.
target_link_libraries(MyFirst Qt5::Widgets)