Development/Tutorials/KCmdLineArgs/KF5

Command line arguments (Under construction User:milliams)

Tutorial Series	Beginner Tutorial
Previous	Tutorial 4 - Loading and saving
What's Next	Tutorial 6 - ### (TODO User:milliams)
Further Reading	KCmdLineArgs KCmdLineOptions

Abstract

Now that we have a text editor which can open and save files. We will now make the editor act more like a desktop application by enabling it to open files from command line arguments or even using Open with from within Dolphin.

The Code

main.cpp

#include <cstdlib>
 
#include <QApplication>
#include <QCommandLineParser>
#include <QUrl>
#include <QDir>

#include <KAboutData>
#include <KLocalizedString>

#include "mainwindow.h"
 
int main (int argc, char *argv[])
{
    QApplication app(argc, argv);
    
    KLocalizedString::setApplicationDomain("tutorial5");
    
    KAboutData aboutData(
                         // The program name used internally. (componentName)
                         QStringLiteral("tutorial5"),
                         // A displayable program name string. (displayName)
                         i18n("Tutorial 5"),
                         // The program version string. (version)
                         QStringLiteral("1.0"),
                         // Short description of what the app does. (shortDescription)
                         i18n("A simple text area which can load and save."),
                         // The license this code is released under
                         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"));
    
    KAboutData::setApplicationData(aboutData);
 
    QCommandLineParser parser;
    parser.addHelpOption();
    parser.addVersionOption();
    parser.addPositionalArgument(QStringLiteral("file"), i18n("Document to open"));
    
    aboutData.setupCommandLine(&parser);
    parser.process(app);
    
    aboutData.processCommandLine(&parser);
    
    MainWindow* window = new MainWindow();
    window->show();
    
    if (parser.positionalArguments().count() > 0)
    {
        window->openFile(QUrl::fromUserInput(parser.positionalArguments().at(0), QDir::currentPath()));
    }
    
    return app.exec();
}

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <KXmlGuiWindow>

class KTextEdit;
class KJob;
 
class MainWindow : public KXmlGuiWindow
{
    Q_OBJECT
    
  public:
    MainWindow(QWidget *parent=0);
    void openFile(const QUrl &inputFileName);
 
  private:
    KTextEdit* textArea;
    void setupActions();
    
    QString fileName;
 
  private slots:
    void newFile();
    void openFile();
    void saveFile();
    void saveFileAs();
    void saveFileAs(const QString &outputFileName);
    
    void downloadFinished(KJob* job);
};
 
#endif

mainwindow.cpp

#include <QApplication>
#include <QAction>
#include <QSaveFile>
#include <QFileDialog>
#include <QTextStream>
#include <QByteArray>

#include <KTextEdit>
#include <KLocalizedString>
#include <KActionCollection>
#include <KStandardAction>
#include <KMessageBox>
#include <KIO/Job>

#include "mainwindow.h"

MainWindow::MainWindow(QWidget *parent) : KXmlGuiWindow(parent), fileName(QString())
{
  textArea = new KTextEdit();
  setCentralWidget(textArea);
  
  setupActions();
}

void MainWindow::setupActions()
{
    QAction* clearAction = new QAction(this);
    clearAction->setText(i18n("&Clear"));
    clearAction->setIcon(QIcon::fromTheme("document-new"));
    actionCollection()->setDefaultShortcut(clearAction, Qt::CTRL + Qt::Key_W);
    actionCollection()->addAction("clear", clearAction);
    connect(clearAction, SIGNAL(triggered(bool)), textArea, SLOT(clear()));
    
    KStandardAction::quit(qApp, SLOT(quit()), actionCollection());
    
    KStandardAction::open(this, SLOT(openFile()), actionCollection());
 
    KStandardAction::save(this, SLOT(saveFile()), actionCollection());
 
    KStandardAction::saveAs(this, SLOT(saveFileAs()), actionCollection());
 
    KStandardAction::openNew(this, SLOT(newFile()), actionCollection());
    
    setupGUI(Default, "tutorial5ui.rc");
}

void MainWindow::newFile()
{
    fileName.clear();
    textArea->clear();
}

void MainWindow::saveFileAs(const QString &outputFileName)
{
    if (!outputFileName.isNull())
    {
        QSaveFile file(outputFileName);
        file.open(QIODevice::WriteOnly);
        
        QByteArray outputByteArray;
        outputByteArray.append(textArea->toPlainText().toUtf8());
        file.write(outputByteArray);
        file.commit();

        fileName = outputFileName;
    }
}

void MainWindow::saveFileAs()
{
    saveFileAs(QFileDialog::getSaveFileName(this, i18n("Save File As")));
}

void MainWindow::saveFile()
{
    if (!fileName.isEmpty())
    {
        saveFileAs(fileName);
    }
    else
    {
        saveFileAs();
    }
}


void MainWindow::openFile()
{
    openFile(QFileDialog::getOpenFileUrl(this, i18n("Open File")));
}
    
void MainWindow::openFile(const QUrl &inputFileName)
{
    if (!inputFileName.isEmpty())
    {
        KIO::Job* job = KIO::storedGet(inputFileName);
        fileName = inputFileName.toLocalFile();

        connect(job, SIGNAL(result(KJob*)), this, SLOT(downloadFinished(KJob*)));
        
        job->exec();
    }
}

void MainWindow::downloadFinished(KJob* job)
{
    if (job->error())
    {
        KMessageBox::error(this, job->errorString());
        fileName.clear();
        return;
    }
    
    KIO::StoredTransferJob* storedJob = (KIO::StoredTransferJob*)job;
    textArea->setPlainText(QTextStream(storedJob->data(), QIODevice::ReadOnly).readAll());
}

tutorial5ui.rc

<?xml version="1.0" encoding="UTF-8"?>
<gui name="tutorial5"
     version="1"
     xmlns="http://www.kde.org/standards/kxmlgui/1.0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://www.kde.org/standards/kxmlgui/1.0
                         http://www.kde.org/standards/kxmlgui/1.0/kxmlgui.xsd" >
 
  <MenuBar>
    <Menu name="file" >
      <Action name="clear" />
    </Menu>
  </MenuBar>
 
  <ToolBar name="mainToolBar" >
    <text>Main Toolbar</text>
    <Action name="clear" />
  </ToolBar>
 
</gui>

Explanation

mainwindow.h

Here we have done nothing but add a new openFile function which takes a QString

void openFile(const QString &inputFileName);

mainwindow.cpp

There's no new code here, only rearranging. Everything from void openFile() has been moved into void openFile(const QString &inputFileName) except the call to KFileDialog::getOpenFileName().

This way, we can call openFile() if we want to display a dialog, or we can call openFile(QString) if we know the name of the file already.

main.cpp

This is where all the KCmdLineArgs magic happens.

Make, Install and Run

CMakeLists.txt

project (tutorial5)

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

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_package(Qt5 ${QT_MIN_VERSION} CONFIG REQUIRED COMPONENTS 
    Core    # QCommandLineParser, QStringLiteral, QSaveFile, QTextStream, QByteArray
    Widgets # QApplication, QAction, QFileDialog
)

find_package(KF5 ${KF5_MIN_VERSION} REQUIRED COMPONENTS
    CoreAddons      # KAboutData
    I18n            # KLocalizedString
    XmlGui          # KXmlGuiWindow, KActionCollection
    TextWidgets     # KTextEdit
    ConfigWidgets   # KStandardActions
    WidgetsAddons   # KMessageBox
    KIO             # KIO
)
    
feature_summary(WHAT ALL INCLUDE_QUIET_PACKAGES FATAL_ON_MISSING_REQUIRED_PACKAGES)
    
set(tutorial5_SRCS main.cpp mainwindow.cpp)

add_executable(tutorial5 ${tutorial5_SRCS})

target_link_libraries(tutorial5
    Qt5::Widgets
    KF5::CoreAddons
    KF5::I18n
    KF5::XmlGui
    KF5::TextWidgets
    KF5::ConfigWidgets
    KF5::WidgetsAddons
    KF5::KIOCore
)

install(TARGETS tutorial5  ${INSTALL_TARGETS_DEFAULT_ARGS})

install(FILES tutorial5ui.rc DESTINATION ${KXMLGUI_INSTALL_DIR}/tutorial5)