Development/Tutorials/First program/KF5

Hello World

Tutorial Series	Beginner Tutorial
Previous	C++, Qt, Building KDE
What's Next	Tutorial 2 - KXmlGuiWindow
Further Reading	CMake

Abstract

KDE Frameworks 5 version of Tutorial1.

The Code

#include <cstdlib>
 
#include <QApplication>
#include <QCommandLineParser>

#include <KAboutData>
#include <KLocalizedString>
#include <KMessageBox>
 
int main (int argc, char *argv[])
{
    // 1
    QApplication app(argc, argv);
    
    // 2
    KLocalizedString::setApplicationDomain("tutorial1");
    
    // 3 new KAboutData constructor
    KAboutData aboutData(
                         // The program name used internally. (componentName)
                         QStringLiteral("tutorial1"),
                         // A displayable program name string. (displayName)
                         // 4
                         i18n("Tutorial 1"),
                         // The program version string. (version)
                         QStringLiteral("1.0"),
                         // Short description of what the app does. (shortDescription)
                         i18n("Displays a KMessageBox popup"),
                         // The license this code is released under
                         // 5
                         KAboutLicense::GPL,
                         // Copyright Statement (copyrightStatement = QString())
                         i18n("(c) 2015"),
                         // Optional text shown in the About box.
                         // Can contain any information desired. (otherText)
                         i18n("Some text..."),
                         // The program homepage string. (homePageAddress = QString())
                         QStringLiteral("http://example.com/"),
                         // The bug report email address
                         // (bugsEmailAddress = QLatin1String("[email protected]")
                         QStringLiteral("[email protected]"));
    
    aboutData.addAuthor(i18n("Name"), i18n("Task"), QStringLiteral("[email protected]"),
                         QStringLiteral("http://your.website.com"), QStringLiteral("OSC Username"));
    
    // 6
    KAboutData::setApplicationData(aboutData);
 
    // 7
    QCommandLineParser parser;
    parser.addHelpOption();
    parser.addVersionOption();
    aboutData.setupCommandLine(&parser);
    parser.process(app);
    aboutData.processCommandLine(&parser);
    
    KGuiItem yesButton( i18n( "Hello" ), QString(),
                        i18n( "This is a tooltip" ),
                        i18n( "This is a WhatsThis help text." ) );

    return 
        KMessageBox::questionYesNo 
        (0, i18n( "Hello World" ), i18n( "Hello" ), yesButton ) 
        == KMessageBox::Yes? EXIT_SUCCESS: EXIT_FAILURE;
}

Notes

1. no more KApplication https://community.kde.org/Frameworks/Porting_Notes#Application
2. no more KAboutAdata catalogName https://community.kde.org/Frameworks/Porting_Notes#KAboutData
3. new KAboutData constructor http://api.kde.org/frameworks-api/frameworks5-apidocs/kcoreaddons/html/classKAboutData.html
4. use i18n for general and immediate cases, ki18n for special KF5 Cookbook https://books.kde.org/frameworks5/KDE-Frameworks-Cookbook.html#writing-messages
5. license keys http://api.kde.org/frameworks-api/frameworks5-apidocs/kcoreaddons/html/classKAboutLicense.html#a29386ce80267871552aedd21d9ce6bbb
6. Set about data https://mail.kde.org/pipermail/kde-frameworks-devel/2015-June/024983.html
7. new way to parse command line arguments https://community.kde.org/Frameworks/Porting_Notes#KCmdLineArgs

CMakeLists.txt

project (tutorial1)

#1
cmake_minimum_required(VERSION 2.8.12 FATAL_ERROR)
set(QT_MIN_VERSION "5.3.0")
set(KF5_MIN_VERSION "5.2.0")

#2
find_package(ECM 1.0.0 REQUIRED NO_MODULE)
set(CMAKE_MODULE_PATH ${ECM_MODULE_PATH} ${ECM_KDE_MODULE_DIR} ${CMAKE_CURRENT_SOURCE_DIR}/cmake)

include(KDEInstallDirs)
include(KDECMakeSettings)
include(KDECompilerSettings)
include(FeatureSummary)

# Find Qt modules
find_package(Qt5 ${QT_MIN_VERSION} CONFIG REQUIRED COMPONENTS 
    Core    # QCommandLineParser, QStringLiteral
    Widgets # QApplication 
)

# Find KDE modules
find_package(KF5 ${KF5_MIN_VERSION} REQUIRED COMPONENTS
    CoreAddons      # KAboutData
    I18n            # KLocalizedString
    WidgetsAddons   # KMessageBox
)

feature_summary(WHAT ALL INCLUDE_QUIET_PACKAGES FATAL_ON_MISSING_REQUIRED_PACKAGES)
    
set(tutorial1_SRCS main.cpp)

# just plain add_executable
add_executable(tutorial1 ${tutorial1_SRCS})

# module-based linking
target_link_libraries(tutorial1
    Qt5::Widgets
    KF5::CoreAddons
    KF5::I18n
    KF5::WidgetsAddons
)

install(TARGETS tutorial1  ${INSTALL_TARGETS_DEFAULT_ARGS})

Notes

1. KF5 Cookbook https://techbase.kde.org/Books
2. https://community.kde.org/Frameworks/Porting_Notes#Build_System