Development/Tutorials/KCmdLineArgs: Difference between revisions

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{{Template:I18n/Language Navigation Bar|Development/Tutorials/KCmdLineArgs}}
 


{{TutorialBrowser|
{{TutorialBrowser|
Line 5: Line 5:
series=Beginner Tutorial|
series=Beginner Tutorial|


name=Command line arguments (Under construction [[User:milliams]])|
name=Command line arguments|


pre=[[Development/Tutorials/Saving and loading|Tutorial 4 - Loading and saving]]|
pre=[[Development/Tutorials/Saving and loading|Tutorial 4 - Loading and saving]]|


next=[[Development/Tutorials/###|Tutorial 6 - ###]] (TODO [[User:milliams]])|
}}


reading={{class|KCmdLineArgs}} {{class|KCmdLineOptions}}
}}


==Abstract==
==Abstract==
Line 18: Line 16:
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.
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.


[[image:introtokdetutorial5.png|frame|center]]
[[image:tutorial5-kf5.png|frame|center]]


== The Code ==
== The Code ==


===main.cpp===
===main.cpp===
<code cppqt n>
<syntaxhighlight lang="cpp-qt">
#include <KApplication>
#include <cstdlib>
#include <QApplication>
#include <QCommandLineParser>
#include <QUrl>
#include <QDir>
 
#include <KAboutData>
#include <KAboutData>
#include <KCmdLineArgs>
#include <KLocalizedString>
#include <KUrl> //new
 
#include "mainwindow.h"
#include "mainwindow.h"
   
   
int main (int argc, char *argv[])
int main (int argc, char *argv[])
{
{
  KAboutData aboutData( "tutorial5", "tutorial5",
    QApplication app(argc, argv);
      ki18n("Tutorial 5"), "1.0",
   
      ki18n("A simple text area which can load and save."),
    KLocalizedString::setApplicationDomain("tutorial5");
      KAboutData::License_GPL,
   
      ki18n("Copyright (c) 2007 Developer") );
    KAboutData aboutData(
  KCmdLineArgs::init( argc, argv, &aboutData );
                        // The program name used internally. (componentName)
 
                        QStringLiteral("tutorial5"),
  KCmdLineOptions options; //new
                        // A displayable program name string. (displayName)
  options.add("+[file]", ki18n("Document to open")); //new
                        i18n("Tutorial 5"),
  KCmdLineArgs::addCmdLineOptions(options); //new
                        // The program version string. (version)
 
                        QStringLiteral("1.0"),
  KApplication app;
                        // 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);
   
   
  MainWindow* window = new MainWindow();
    QCommandLineParser parser;
  window->show();
    parser.addHelpOption();
 
    parser.addVersionOption();
  KCmdLineArgs *args = KCmdLineArgs::parsedArgs(); //new
    parser.addPositionalArgument(QStringLiteral("file"), i18n("Document to open"));
  if(args->count()) //new
   
  {
    aboutData.setupCommandLine(&parser);
    window->openFile(args->url(0).url()); //new
    parser.process(app);
  }
   
 
    aboutData.processCommandLine(&parser);
  return app.exec();
   
    MainWindow* window = new MainWindow();
    window->show();
   
    if (parser.positionalArguments().count() > 0)
    {
        window->openFile(QUrl::fromUserInput(parser.positionalArguments().at(0), QDir::currentPath()));
    }
   
    return app.exec();
}
}
</code>
</syntaxhighlight>


===mainwindow.h===
===mainwindow.h===
<code cppqt n>
<syntaxhighlight lang="cpp-qt">
#ifndef MAINWINDOW_H
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#define MAINWINDOW_H
   
   
#include <KXmlGuiWindow>
#include <KXmlGuiWindow>
#include <KTextEdit>
 
class KTextEdit;
class KJob;
   
   
class MainWindow : public KXmlGuiWindow
class MainWindow : public KXmlGuiWindow
{
{
  Q_OBJECT
    Q_OBJECT
 
   
   public:
   public:
     MainWindow(QWidget *parent=0);
     MainWindow(QWidget *parent=0);
     void openFile(const QString &inputFileName); //new
     void openFile(const QUrl &inputFileName);
 
   private:
   private:
     KTextEdit* textArea;
     KTextEdit* textArea;
     void setupActions();
     void setupActions();
   
     QString fileName;
     QString fileName;
   
   
Line 86: Line 119:
     void saveFileAs();
     void saveFileAs();
     void saveFileAs(const QString &outputFileName);
     void saveFileAs(const QString &outputFileName);
   
    void downloadFinished(KJob* job);
};
};
   
   
#endif
#endif
</code>
</syntaxhighlight>


===mainwindow.cpp===
===mainwindow.cpp===
<code cppqt n>
<syntaxhighlight lang="cpp-qt">
#include "mainwindow.h"
#include <QApplication>
#include <QAction>
#include <KApplication>
#include <QSaveFile>
#include <KAction>
#include <QFileDialog>
#include <KLocale>
#include <QTextStream>
#include <QByteArray>
 
#include <KTextEdit>
#include <KLocalizedString>
#include <KActionCollection>
#include <KActionCollection>
#include <KStandardAction>
#include <KStandardAction>
#include <KFileDialog>
#include <KMessageBox>
#include <KMessageBox>
#include <KIO/NetAccess>
#include <KIO/Job>
#include <KSaveFile>
 
#include <QTextStream>
#include "mainwindow.h"
 
MainWindow::MainWindow(QWidget *parent)
MainWindow::MainWindow(QWidget *parent) : KXmlGuiWindow(parent), fileName(QString())
    : KXmlGuiWindow(parent),
      fileName(QString())
{
{
   textArea = new KTextEdit;
   textArea = new KTextEdit();
   setCentralWidget(textArea);
   setCentralWidget(textArea);
 
   setupActions();
   setupActions();
}
}
 
void MainWindow::setupActions()
void MainWindow::setupActions()
{
{
  KAction* clearAction = new KAction(this);
    QAction* clearAction = new QAction(this);
  clearAction->setText(i18n("Clear"));
    clearAction->setText(i18n("&Clear"));
  clearAction->setIcon(KIcon("document-new"));
    clearAction->setIcon(QIcon::fromTheme("document-new"));
  clearAction->setShortcut(Qt::CTRL + Qt::Key_W);
    actionCollection()->setDefaultShortcut(clearAction, Qt::CTRL + Qt::Key_W);
  actionCollection()->addAction("clear", clearAction);
    actionCollection()->addAction("clear", clearAction);
  connect(clearAction, SIGNAL(triggered(bool)),
    connect(clearAction, SIGNAL(triggered(bool)), textArea, SLOT(clear()));
          textArea, SLOT(clear()));
   
    KStandardAction::quit(qApp, SLOT(quit()), actionCollection());
  KStandardAction::quit(kapp, SLOT(quit()),
   
                        actionCollection());
    KStandardAction::open(this, SLOT(openFile()), actionCollection());
   
   
  KStandardAction::open(this, SLOT(openFile()),
    KStandardAction::save(this, SLOT(saveFile()), actionCollection());
                        actionCollection());
   
   
  KStandardAction::save(this, SLOT(saveFile()),
    KStandardAction::saveAs(this, SLOT(saveFileAs()), actionCollection());
                        actionCollection());
   
   
  KStandardAction::saveAs(this, SLOT(saveFileAs()),
    KStandardAction::openNew(this, SLOT(newFile()), actionCollection());
                        actionCollection());
   
    setupGUI(Default, "tutorial5ui.rc");
  KStandardAction::openNew(this, SLOT(newFile()),
                        actionCollection());
  setupGUI();
}
}
 
void MainWindow::newFile()
void MainWindow::newFile()
{
{
  fileName.clear();
    fileName.clear();
  textArea->clear();
    textArea->clear();
}
}
 
void MainWindow::saveFileAs(const QString &outputFileName)
void MainWindow::saveFileAs(const QString &outputFileName)
{
{
  KSaveFile file(outputFileName);
    if (!outputFileName.isNull())
  file.open();
    {
 
        QSaveFile file(outputFileName);
  QByteArray outputByteArray;
        file.open(QIODevice::WriteOnly);
  outputByteArray.append(textArea->toPlainText());
       
  file.write(outputByteArray);
        QByteArray outputByteArray;
  file.finalize();
        outputByteArray.append(textArea->toPlainText().toUtf8());
  file.close();
        file.write(outputByteArray);
 
        file.commit();
  fileName = outputFileName;
 
        fileName = outputFileName;
    }
}
}
 
void MainWindow::saveFileAs()
void MainWindow::saveFileAs()
{
{
  saveFileAs(KFileDialog::getSaveFileName());
    saveFileAs(QFileDialog::getSaveFileName(this, i18n("Save File As")));
}
}
 
void MainWindow::saveFile()
void MainWindow::saveFile()
{
{
  if(!fileName.isEmpty())
    if (!fileName.isEmpty())
  {
    {
    saveFileAs(fileName);
        saveFileAs(fileName);
  }
    }
  else
    else
  {
    {
    saveFileAs();
        saveFileAs();
  }
    }
}
 
 
void MainWindow::openFile()
{
    openFile(QFileDialog::getOpenFileUrl(this, i18n("Open File")));
}
}
   
void MainWindow::openFile() //changed
void MainWindow::openFile(const QUrl &inputFileName)
{
{
  openFile(KFileDialog::getOpenFileName());
    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::openFile(const QString &inputFileName) //new
void MainWindow::downloadFinished(KJob* job)
{
{
  QString tmpFile;
    if (job->error())
  if(KIO::NetAccess::download(inputFileName, tmpFile,
    {
        this))
        KMessageBox::error(this, job->errorString());
  {
        fileName.clear();
    QFile file(tmpFile);
        return;
    file.open(QIODevice::ReadOnly);
     }
    textArea->setPlainText(QTextStream(&file).readAll());
   
     fileName = inputFileName;
     KIO::StoredTransferJob* storedJob = (KIO::StoredTransferJob*)job;
     textArea->setPlainText(QTextStream(storedJob->data(), QIODevice::ReadOnly).readAll());
     KIO::NetAccess::removeTempFile(tmpFile);
  }
  else
  {
     KMessageBox::error(this,  
        KIO::NetAccess::lastErrorString());
  }
}
}
</code>
</syntaxhighlight>


===tutorial5ui.rc===
===tutorial5ui.rc===
<code xml n>
<syntaxhighlight lang="xml">
<?xml version="1.0" encoding="UTF-8"?>
<?xml version="1.0" encoding="UTF-8"?>
<gui name="tutorial5"
<gui name="tutorial5"
Line 216: Line 255:
     xsi:schemaLocation="http://www.kde.org/standards/kxmlgui/1.0
     xsi:schemaLocation="http://www.kde.org/standards/kxmlgui/1.0
                         http://www.kde.org/standards/kxmlgui/1.0/kxmlgui.xsd" >
                         http://www.kde.org/standards/kxmlgui/1.0/kxmlgui.xsd" >
 
   <MenuBar>
   <MenuBar>
     <Menu name="file" >
     <Menu name="file" >
Line 222: Line 261:
     </Menu>
     </Menu>
   </MenuBar>
   </MenuBar>
 
   <ToolBar name="mainToolBar" >
   <ToolBar name="mainToolBar" >
     <text>Main Toolbar</text>
     <text>Main Toolbar</text>
     <Action name="clear" />
     <Action name="clear" />
   </ToolBar>
   </ToolBar>
 
</gui>
</gui>
</code>
</syntaxhighlight>
This is identical to the <tt>tutorial''x''ui.rc</tt> from the last two tutorials except <tt>tutorial''x''</tt> is now <tt>tutorial5</tt>.


==Explanation==
==Explanation==
Line 236: Line 274:
===mainwindow.h===
===mainwindow.h===


Here we have done nothing but add a new <tt>openFile</tt> function which takes a <tt>QString</tt>
Here we have done nothing but add a new <tt>openFile</tt> function which takes a <tt>QUrl</tt>. Again, we use a QUrl instead of a QString so that we can also work with remote files as if they were local.
<code cppqt>
<syntaxhighlight lang="cpp-qt">
void openFile(const QString &inputFileName);
void openFile(const QUrl &inputFileName);
</code>
</syntaxhighlight>


===mainwindow.cpp===
===mainwindow.cpp===


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


This way, we can call <tt>openFile()</tt> if we want to display a dialog, or we can call <tt>openFile(QString)</tt> if we know the name of the file already.
This way, we can call <tt>openFile()</tt> if we want to display a dialog, or we can call <tt>openFile(QString)</tt> if we know the name of the file already. Which will be the case when we feed the file name through the command line.


===main.cpp===
===main.cpp===


This is where all the {{class|KCmdLineArgs}} magic happens.
This is where all the [http://doc.qt.io/qt-5/qcommandlineparser.html QCommandLineParser] magic happens. In previous examples, we only used the class to feed QApplication the necessary data for using flags like <tt>--version</tt> or <tt>--author</tt>. Now we actually get to use it to process command line arguments.


==Make, Install And Run==
First, we tell QCommandLineParser that we want to add a new positional arguments. In a nutshell, these are arguments that are not options. <tt>-h</tt> or <tt>--version</tt> are options, <tt>file</tt> is an argument.
<syntaxhighlight lang="cpp-qt">
parser.addPositionalArgument(QStringLiteral("file"), i18n("Document to open"));
</syntaxhighlight>
 
 
Later on, we start processing positional arguments, but only if there is one. Otherwise, we proceed as usual. In our case we can only open one file at a time, so only the first file is of interest to us. We call the <tt>openFile()</tt> function and feed it the URL of the file we want to open, whether it is a local file like {{path|$HOME/foo}} or a remote one like {{path|ftp.mydomain.com/bar}}. We use the overloaded form of <tt>[http://doc.qt.io/qt-5/qurl.html#fromUserInput-1 QUrl::fromUserInput()]</tt> in order to set the current path. This is needed in order to work with relative paths like <tt>"../baz"</tt>.
<syntaxhighlight lang="cpp-qt">
if (parser.positionalArguments().count() > 0)
{
    window->openFile(QUrl::fromUserInput(parser.positionalArguments().at(0), QDir::currentPath()));
}
</syntaxhighlight>
 
==Make, Install and Run==


===CMakeLists.txt===
===CMakeLists.txt===
<code ini n>
<syntaxhighlight lang="cmake">
project(tutorial5)
project (tutorial5)
 
find_package(KDE4 REQUIRED)
cmake_minimum_required(VERSION 2.8.12 FATAL_ERROR)
include_directories( ${KDE4_INCLUDES} )
set(QT_MIN_VERSION "5.3.0")
set(KF5_MIN_VERSION "5.2.0")
set(tutorial5_SRCS  
 
  main.cpp
find_package(ECM 1.0.0 REQUIRED NO_MODULE)
  mainwindow.cpp
set(CMAKE_MODULE_PATH ${ECM_MODULE_PATH} ${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
)
)
 
kde4_add_executable(tutorial5 ${tutorial5_SRCS})
install(TARGETS tutorial5  ${INSTALL_TARGETS_DEFAULT_ARGS})
   
 
target_link_libraries(tutorial5 ${KDE4_KDEUI_LIBS}
install(FILES tutorial5ui.rc DESTINATION ${KXMLGUI_INSTALL_DIR}/tutorial5)
                                ${KDE4_KIO_LIBS})
</syntaxhighlight>
 
install(TARGETS tutorial5 DESTINATION ${BIN_INSTALL_DIR})
install( FILES tutorial5ui.rc  
        DESTINATION ${DATA_INSTALL_DIR}/tutorial5 )
</code>


With this file, the tutorial can built and run in the same way as tutorial 3 and 4. For more information, see tutorial 3.
With this file, the tutorial can built and run in the same way as tutorial 3 and 4. For more information, see tutorial 3.
<syntaxhighlight lang="bash">
mkdir build && cd build
cmake .. -DCMAKE_INSTALL_PREFIX=$HOME
make install
XDG_DATA_DIRS=$HOME/share:$XDG_DATA_DIRS $HOME/bin/tutorial5
</syntaxhighlight>


mkdir build && cd build
cmake .. -DCMAKE_INSTALL_PREFIX=$HOME
make install
$HOME/bin/tutorial5


==Moving On==
{{Attention||The source code on this page applies only the current KDE Frameworks 5 ("KF5") version. For the older KDE Development Platform ("KDE4"), See [[Development/Tutorials/First_program/KDE4]]}}
Now you can move on to the ### (TODO [[User:milliams]]) tutorial.


[[Category:C++]]
[[Category:C++]]

Latest revision as of 18:04, 18 April 2020


Command line arguments
Tutorial Series   Beginner Tutorial
Previous   Tutorial 4 - Loading and saving
What's Next   n/a
Further Reading   n/a


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 QUrl. Again, we use a QUrl instead of a QString so that we can also work with remote files as if they were local.

void openFile(const QUrl &inputFileName);

mainwindow.cpp

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

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. Which will be the case when we feed the file name through the command line.

main.cpp

This is where all the QCommandLineParser magic happens. In previous examples, we only used the class to feed QApplication the necessary data for using flags like --version or --author. Now we actually get to use it to process command line arguments.

First, we tell QCommandLineParser that we want to add a new positional arguments. In a nutshell, these are arguments that are not options. -h or --version are options, file is an argument.

parser.addPositionalArgument(QStringLiteral("file"), i18n("Document to open"));


Later on, we start processing positional arguments, but only if there is one. Otherwise, we proceed as usual. In our case we can only open one file at a time, so only the first file is of interest to us. We call the openFile() function and feed it the URL of the file we want to open, whether it is a local file like $HOME/foo or a remote one like ftp.mydomain.com/bar. We use the overloaded form of QUrl::fromUserInput() in order to set the current path. This is needed in order to work with relative paths like "../baz".

if (parser.positionalArguments().count() > 0)
{
    window->openFile(QUrl::fromUserInput(parser.positionalArguments().at(0), QDir::currentPath()));
}

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} ${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)


With this file, the tutorial can built and run in the same way as tutorial 3 and 4. For more information, see tutorial 3.

mkdir build && cd build
cmake .. -DCMAKE_INSTALL_PREFIX=$HOME
make install
XDG_DATA_DIRS=$HOME/share:$XDG_DATA_DIRS $HOME/bin/tutorial5


The source code on this page applies only the current KDE Frameworks 5 ("KF5") version. For the older KDE Development Platform ("KDE4"), See Development/Tutorials/First_program/KDE4