Building Qt5 Quick project without Qt Creator via CMake

Question

Im trying to build simple Qt Quick project and want to work with it outside Qt Creator. It means coding, building and running program only with tools like Vim or CMake.

I have two problems:

I don't understand why CMake cannot find all needed libraries by itself and build project.
I don't understand why clicking on ▶ button in Qt Creator builds default project succesfully, but running CMake by myself results in c++ error.

Firstly i made CMakeLists.txt in the image of Qt5 Quick project i found on github. Then I tried to make project via Creator, then inspect how it builds CMakeLists.txt and compose one by myself.

My first attempt:

cmake_minimum_required(VERSION 3.11..3.15)

set(PROJECT_NAME "uint32_sort_gui")

project(${PROJECT_NAME} LANGUAGES CXX)

set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)
set(CMAKE_AUTOUIC ON)

find_package(Qt5 COMPONENTS Core Gui Qml Quick QuickControls2 REQUIRED)

add_subdirectory(${PROJECT_SOURCE_DIR}/sort_lib/)

target_link_libraries(${PROJECT_NAME}
                      PUBLIC
                      Qt5::Core
                      Qt5::Gui
                      Qt5::Qml
                      Qt5::Quick
                      Qt5::QuickControls2    #(*)
                      SortCore
                      )
set_target_properties(${PROJECT_NAME} 
                      PROPERTIES 
                      CXX_STANDARD 11 
                      CXX_STANDARD_REQUIRED ON)

Second (autogenerated by Qt Creator):

cmake_minimum_required(VERSION 3.1)

project(Deleteme2 LANGUAGES CXX)

set(CMAKE_INCLUDE_CURRENT_DIR ON)
set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

find_package(Qt5 COMPONENTS Core Quick REQUIRED)

add_executable(${PROJECT_NAME} "main.cpp" "qml.qrc")
target_compile_definitions(${PROJECT_NAME} PRIVATE $<$<OR:$<CONFIG:Debug>,$<CONFIG:RelWithDebInfo>>:QT_QML_DEBUG>)
target_link_libraries(${PROJECT_NAME} PRIVATE Qt5::Core Qt5::Quick)

First listing fails on (*) line, saying

Could not find a package configuration file provided by "Qt5QuickControls2"
  with any of the following names:

    Qt5QuickControls2Config.cmake
    qt5quickcontrols2-config.cmake

  Add the installation prefix of "Qt5QuickControls2" to CMAKE_PREFIX_PATH or
  set "Qt5QuickControls2_DIR" to a directory containing one of the above
  files.  If "Qt5QuickControls2" provides a separate development package or
  SDK, be sure it has been installed.

(But i've installed everything)

And second fails with error during compilation:

make
[ 16%] Automatic MOC for target Deleteme2
[ 16%] Built target Deleteme2_autogen
[ 33%] Building CXX object CMakeFiles/Deleteme2.dir/main.cpp.o
Deleteme2/main.cpp: In function ‘int main(int, char**)’:
Deleteme2/main.cpp:6:36: error: ‘AA_EnableHighDpiScaling’ is not a member of ‘Qt’
     QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

What am i doing wrong? Why Qt Creator can build Deleteme2 without a problem?

Edited: Here is the sample code, generated by Qt Creator for second attempt

#include <QGuiApplication>
#include <QQmlApplicationEngine>

int main(int argc, char *argv[])
{
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

    QGuiApplication app(argc, argv);

    QQmlApplicationEngine engine;
    const QUrl url(QStringLiteral("qrc:/main.qml"));
    QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
                     &app, [url](QObject *obj, const QUrl &objUrl) {
        if (!obj && url == objUrl)
            QCoreApplication::exit(-1);
    }, Qt::QueuedConnection);
    engine.load(url);

    return app.exec();
}

nonForgivingJesus nonForgivingJesus · Accepted Answer · 2019-08-01T09:03:28

The main problem, why "First attempt" failed is because Qt5 installed itself in ~/Qt and CMake searched for *.cmake configuration files in /usr/lib/x86_64-linux-gnu/cmake/ (I didn't metion that i use Ubuntu 16 LTS, which have cmake 3.5.1 preinstalled).

So the way to solve this problem was to copy everything that was in

~/Qt/*last cmake version*/gcc_64 (in my case ~/Qt/5.13.0/gcc_64)

into /usr/lib/ via sudo cp -a ~/Qt/5.13.0/gcc_64/* /usr/lib/

The answer to second is short:

This happend because by default Qt Creator sets CMake output into Ninja makefiles.

Go to Tools > Options > Kits and add desired configuration or edit existing.

Building Qt5 Quick project without Qt Creator via CMake

1 Answers