Merge pull request cpp-best-practices#6 from paulbendixen/add_qt_gui

Add qt gui

Author: lefticus

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.2)
+cmake_minimum_required(VERSION 3.8)
 
 option(BUILD_SHARED_LIBS "Enable compilation of shared libraries" FALSE)
 
@@ -55,23 +55,33 @@ enable_testing()
 
 add_executable(tester tester.cpp)
 target_link_libraries(tester PRIVATE project_warnings --coverage)
-
 add_test(Tester tester)
 
+#qt
+if( DEFINED CPP_STARTER_USE_QT )
+message( "Using Qt" )
+add_subdirectory(qt)
+endif()
+
 #fltk test
+if( DEFINED CPP_STARTER_USE_FLTK )
 find_package(FLTK REQUIRED)
 add_executable(test_fltk fltk/test_fltk.cpp)
 target_link_libraries(test_fltk PRIVATE project_warnings ${FLTK_LIBRARIES})
 target_include_directories(test_fltk PRIVATE ${FLTK_INCLUDE_DIR})
+endif()
 
 # gtkmm test
+if( DEFINED CPP_STARTER_USE_GTKMM )
 find_package(PkgConfig REQUIRED)
 pkg_check_modules(GTKMM REQUIRED gtkmm-3.0)
 add_executable(test_gtkmm gtkmm/main.cpp gtkmm/hello_world.cpp)
 target_link_libraries(test_gtkmm PRIVATE project_warnings ${GTKMM_LIBRARIES})
 target_include_directories(test_gtkmm PRIVATE ${GTKMM_INCLUDE_DIRS})
+endif()
 
 # imgui example
+if( DEFINED CPP_STARTER_USE_IMGUI )
 find_package(SFML COMPONENTS graphics window system)
 find_package(OpenGL)
 
@@ -83,8 +93,10 @@ target_link_libraries(imgui INTERFACE ${SFML_LIBRARIES} ${OPENGL_gl_LIBRARY})
 add_executable(test_imgui imgui/test.cpp)
 target_link_libraries(test_imgui PRIVATE project_warnings imgui)
 target_include_directories(test_imgui PRIVATE ${SFML_INCLUDE_DIR})
+endif()
 
 # Nana
+if( DEFINED CPP_STARTER_USE_NANA )
 include(ExternalProject)
 ExternalProject_add(
  Nana
@@ -99,5 +111,4 @@ ExternalProject_Get_Property(Nana SOURCE_DIR BINARY_DIR)
 add_executable(test_nana nana/main.cpp)
 target_include_directories(test_nana PRIVATE ${SOURCE_DIR}/include)
 target_link_libraries(test_nana PRIVATE ${BINARY_DIR}/libnana.so ${NANA_LINKS})
-
-
+endif()

qt/CMakeLists.txt

@@ -0,0 +1,6 @@
+find_package( Qt5Widgets REQUIRED )
+set( CMAKE_AUTOMOC ON )
+add_executable( helloQt qtMain.cpp HelloQt.cpp )
+#set_target_properties( helloQt PROPERTIES CMAKE_AUTOMOC ON )
+target_link_libraries( helloQt Qt5::Widgets )
+target_compile_features( helloQt PUBLIC cxx_nullptr cxx_lambdas )

qt/HelloQt.cpp

@@ -0,0 +1,47 @@
+#include "HelloQt.hpp"
+#include <QHBoxLayout>
+#include <QVBoxLayout>
+#include <QPushButton>
+#include <QLabel>
+#include <QDebug>
+
+HelloQt::HelloQt(QWidget *parent) : QWidget(parent) {
+ // The memory management is not done explicitly but by using the parent
+ // relationship built into Qt
+ // The tr calls are not strictly neccesary, but it is all that is needed for
+ // future i18n.
+ auto mainLayout = new QVBoxLayout;
+ auto descriptiveLabel = new QLabel(tr("Descriptive"));
+ auto pushButton = new QPushButton(tr("Push me!"));
+ auto grouping = new QHBoxLayout;
+ auto directButton = new QPushButton(tr("Directly!"));
+ auto fatal = new QPushButton(tr("Don't push this button"));
+ // By adding the widgets to the main widget, they get parented and the
+ // parenting takes care of freeing the memory.
+ // Laying out in layouts makes the GUI automatically resize.
+ grouping->addWidget(descriptiveLabel);
+ grouping->addWidget(pushButton);
+ mainLayout->addLayout(grouping);
+ mainLayout->addWidget(directButton);
+ mainLayout->addWidget(fatal);
+ setLayout(mainLayout);
+ // Signals and slots are use to simply define relationships between actions
+ // and effects
+ // By using this "new style" connect the types are checked at compile time to
+ // match
+ connect(pushButton, &QPushButton::clicked, this, &HelloQt::writeToDebug);
+ // Lambdas can also be used as can ordinary freestanding functions
+ connect(directButton, &QPushButton::clicked,
+ []() { qDebug() << tr("I am in line"); });
+ // Most usefull signals and slots are already built into the framework.
+ connect(fatal, &QPushButton::clicked, this, &HelloQt::close); // could just use close
+};
+
+HelloQt::~HelloQt() {
+ // Nothing to do here, the parent system makes sure that all the elements that
+ // are parented to this is cleaned up
+}
+
+void HelloQt::writeToDebug(void) {
+ qDebug() << tr("I don't know what I was supposed to debug here...");
+}

qt/HelloQt.hpp

@@ -0,0 +1,12 @@
+#include <QWidget>
+
+class HelloQt : public QWidget
+{
+ Q_OBJECT // Very Important, this is all the magic that is needed
+ public:
+ explicit HelloQt(QWidget* parent = nullptr);
+ ~HelloQt();
+ private slots:
+ void writeToDebug();
+
+};

qt/qtMain.cpp

@@ -0,0 +1,12 @@
+#include "HelloQt.hpp"
+#include <QApplication>
+
+int main(int argc, char* argv[])
+{
+ QApplication app(argc, argv);
+ HelloQt dialog;
+ dialog.show();
+
+ return app.exec(); // this runs the main event loop and sees to it that cleanup is done
+}
+