将QT5库添加到CMake

Question

将QT5库添加到CMake

7

我是一名新手，正在使用CMake。我正在尝试创建一个简单的CMakeList文件，并为来自QT5 5.7的QPrinter和QTextDocument添加支持。从我发现的情况来看，我需要将以下库添加到我的CMakeList文件中:

QT5Core
QT5PrintSupport
Qt5Gui
Qt5Widgets

这是我目前的文件内容:

cmake_minimum_required(VERSION 2.8 FATAL_ERROR) 
PROJECT (photobooth)

find_package( Qt5Core )
find_package( Qt5PrintSupport )
find_package( Qt5Gui )
find_package( Qt5Widgets )

set( NAME_SRC
    src/main.cpp
    src/photobooth.cpp      
)

set( NAME_HEADERS 
    include/photobooth.h          

)

INCLUDE_DIRECTORIES( ${CMAKE_CURRENT_SOURCE_DIR}/include )
link_directories( ${CMAKE_BINARY_DIR}/bin)

set(EXECUTABLE_OUTPUT_PATH ${CMAKE_BINARY_DIR}/bin)

add_executable( photobooth ${NAME_SRC} ${NAME_HEADERS} )

target_link_libraries( photobooth Qt5::Widgets )
target_link_libraries( photobooth Qt5::Core )
target_link_libraries( photobooth Qt5::Qt5PrintSupport )
target_link_libraries( photobooth Qt5::Qt5Gui )

以下是Cmake的输出内容:

Configuring done
CMake Warning (dev) in CMakeLists.txt:
  Policy CMP0020 is not set: Automatically link Qt executables to qtmain
  target on Windows.  Run "cmake --help-policy CMP0020" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) in CMakeLists.txt:
  Policy CMP0020 is not set: Automatically link Qt executables to qtmain
  target on Windows.  Run "cmake --help-policy CMP0020" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at CMakeLists.txt:24 (add_executable):
  Policy CMP0028 is not set: Double colon in target name means ALIAS or
  IMPORTED target.  Run "cmake --help-policy CMP0028" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.

  Target "photobooth" links to target "Qt5::Qt5PrintSupport" but the target
  was not found.  Perhaps a find_package() call is missing for an IMPORTED
  target, or an ALIAS target is missing?
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at CMakeLists.txt:24 (add_executable):
  Policy CMP0028 is not set: Double colon in target name means ALIAS or
  IMPORTED target.  Run "cmake --help-policy CMP0028" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.

  Target "photobooth" links to target "Qt5::Qt5Gui" but the target was not
  found.  Perhaps a find_package() call is missing for an IMPORTED target, or
  an ALIAS target is missing?
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) in CMakeLists.txt:
  Policy CMP0020 is not set: Automatically link Qt executables to qtmain
  target on Windows.  Run "cmake --help-policy CMP0020" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at CMakeLists.txt:24 (add_executable):
  Policy CMP0028 is not set: Double colon in target name means ALIAS or
  IMPORTED target.  Run "cmake --help-policy CMP0028" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.

  Target "photobooth" links to target "Qt5::Qt5PrintSupport" but the target
  was not found.  Perhaps a find_package() call is missing for an IMPORTED
  target, or an ALIAS target is missing?
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at CMakeLists.txt:24 (add_executable):
  Policy CMP0028 is not set: Double colon in target name means ALIAS or
  IMPORTED target.  Run "cmake --help-policy CMP0028" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.

  Target "photobooth" links to target "Qt5::Qt5Gui" but the target was not
  found.  Perhaps a find_package() call is missing for an IMPORTED target, or
  an ALIAS target is missing?
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) in CMakeLists.txt:
  Policy CMP0020 is not set: Automatically link Qt executables to qtmain
  target on Windows.  Run "cmake --help-policy CMP0020" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at CMakeLists.txt:24 (add_executable):
  Policy CMP0028 is not set: Double colon in target name means ALIAS or
  IMPORTED target.  Run "cmake --help-policy CMP0028" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.

  Target "photobooth" links to target "Qt5::Qt5PrintSupport" but the target
  was not found.  Perhaps a find_package() call is missing for an IMPORTED
  target, or an ALIAS target is missing?
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at CMakeLists.txt:24 (add_executable):
  Policy CMP0028 is not set: Double colon in target name means ALIAS or
  IMPORTED target.  Run "cmake --help-policy CMP0028" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.

  Target "photobooth" links to target "Qt5::Qt5Gui" but the target was not
  found.  Perhaps a find_package() call is missing for an IMPORTED target, or
  an ALIAS target is missing?
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) in CMakeLists.txt:
  Policy CMP0020 is not set: Automatically link Qt executables to qtmain
  target on Windows.  Run "cmake --help-policy CMP0020" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at CMakeLists.txt:24 (add_executable):
  Policy CMP0028 is not set: Double colon in target name means ALIAS or
  IMPORTED target.  Run "cmake --help-policy CMP0028" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.

  Target "photobooth" links to target "Qt5::Qt5PrintSupport" but the target
  was not found.  Perhaps a find_package() call is missing for an IMPORTED
  target, or an ALIAS target is missing?
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at CMakeLists.txt:24 (add_executable):
  Policy CMP0028 is not set: Double colon in target name means ALIAS or
  IMPORTED target.  Run "cmake --help-policy CMP0028" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.

  Target "photobooth" links to target "Qt5::Qt5Gui" but the target was not
  found.  Perhaps a find_package() call is missing for an IMPORTED target, or
  an ALIAS target is missing?
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) in CMakeLists.txt:
  Policy CMP0020 is not set: Automatically link Qt executables to qtmain
  target on Windows.  Run "cmake --help-policy CMP0020" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) in CMakeLists.txt:
  Policy CMP0020 is not set: Automatically link Qt executables to qtmain
  target on Windows.  Run "cmake --help-policy CMP0020" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) in CMakeLists.txt:
  Policy CMP0020 is not set: Automatically link Qt executables to qtmain
  target on Windows.  Run "cmake --help-policy CMP0020" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) in CMakeLists.txt:
  Policy CMP0020 is not set: Automatically link Qt executables to qtmain
  target on Windows.  Run "cmake --help-policy CMP0020" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at CMakeLists.txt:24 (add_executable):
  Policy CMP0028 is not set: Double colon in target name means ALIAS or
  IMPORTED target.  Run "cmake --help-policy CMP0028" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.

  Target "photobooth" links to target "Qt5::Qt5PrintSupport" but the target
  was not found.  Perhaps a find_package() call is missing for an IMPORTED
  target, or an ALIAS target is missing?
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at CMakeLists.txt:24 (add_executable):
  Policy CMP0028 is not set: Double colon in target name means ALIAS or
  IMPORTED target.  Run "cmake --help-policy CMP0028" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.

  Target "photobooth" links to target "Qt5::Qt5Gui" but the target was not
  found.  Perhaps a find_package() call is missing for an IMPORTED target, or
  an ALIAS target is missing?
This warning is for project developers.  Use -Wno-dev to suppress it.

Generating done

我的项目使用Visual Studio 14 2015 Win64进行构建，生成良好。当我在main.cpp中包含QTextDocument时，它可以找到它，但是找不到QPrinter。是否有什么我做错了的地方？

- ns533

2

也许您忘记了在qmake的include目录中添加内容，例如 target_include_directories(photobooth ${Qt5Widgets_INCLUDE_DIRS})。您看过这个吗？顺便提一下，尝试升级您的cmake版本。 - Stargateur

2个回答

2

您需要使用CMake的“2.8”版本，这个版本太低了，不能使用Qt的一些特性，比如导入目标和在Windows上自动连接qtmain，这正是策略警告的作用所在。

相反，建议使用更高版本的CMake。

cmake_minimium_required(VERSION 2.8.11)

对于这个版本，不再需要使用FATAL_ERROR选项。

请注意，即使您拥有CMake 2.8.12，它也会模拟您在cmake_minimium_required命令中编写的确切版本。

- Tsyvarev

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- rocambille · Accepted Answer

一些提示：

find_package( Qt5Core )
find_package( Qt5PrintSupport )
find_package( Qt5Gui )
find_package( Qt5Widgets )

您可以在一个 find_package 中合并这些调用，以寻找Qt5：

find_package(Qt5 REQUIRED
    Core
    PrintSupport
    Gui
    Widgets
)

注意使用关键字REQUIRED，如果找不到该软件包，CMake将会报错。根据你的错误日志看起来这可能是你的问题所在。你是否在某个地方设置了Qt5_DIR？

这里Core和Gui是可选的，因为Widgets依赖于它们，所以它们将被自动添加。

您应该将CMake的所需版本更改为2.8.11，以确保导入的目标嵌入包含目录。

您应该考虑使用target_include_directories代替INCLUDE_DIRECTORIES以避免全局污染，并将参数附加到目标上。虽然这不是当前问题的实质，但对未来的大型项目来说是一个好的实践。

在此处调用link_directories是无用的。如果需要链接库，请优先使用target_link_libraries。

EXECUTABLE_OUTPUT_PATH是一个旧变量，已经被RUNTIME_OUTPUT_DIRECTORY取代，这是一个目标属性。

清理后，您的CMake项目可能如下所示：

cmake_minimum_required(VERSION 2.8.11 FATAL_ERROR)
PROJECT (photobooth)

find_package(Qt5 REQUIRED
    Widgets
    PrintSupport
)

set( NAME_SRC
    src/main.cpp
    src/photobooth.cpp
)
set( NAME_HEADERS
    include/photobooth.h
)

add_executable( photobooth ${NAME_SRC} ${NAME_HEADERS} )

set_target_properties(photobooth PROPERTIES
    RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin
)

target_include_directories(photobooth PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include)

target_link_libraries( photobooth Qt5::Widgets Qt5::PrintSupport )