Development/Tutorials/KCmdLineArgs

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 <KApplication>
include <KAboutData>
include <KCmdLineArgs>
include <KUrl> //new

include "mainwindow.h"

int main (int argc, char *argv[])
{

 KAboutData aboutData( "tutorial5", "tutorial5",
     ki18n("Tutorial 5"), "1.0",
     ki18n("A simple text area which can load and save."),
     KAboutData::License_GPL,
     ki18n("Copyright (c) 2007 Developer") );
 KCmdLineArgs::init( argc, argv, &aboutData );

 KCmdLineOptions options; //new
 options.add("+[file]", ki18n("Document to open")); //new
 KCmdLineArgs::addCmdLineOptions(options); //new

 KApplication app;

 MainWindow* window = new MainWindow();
 window->show();

 KCmdLineArgs *args = KCmdLineArgs::parsedArgs(); //new
 if(args->count()) //new
 {
   window->openFile(args->url(0).url()); //new
 }

 return app.exec();

}

mainwindow.h

ifndef MAINWINDOW_H
define MAINWINDOW_H

include <KXmlGuiWindow>
include <KTextEdit>

class MainWindow : public KXmlGuiWindow
{

 Q_OBJECT
 
 public:
   MainWindow(QWidget *parent=0);
   void openFile(const QString &inputFileName); //new
 
 private:
   KTextEdit* textArea;
   void setupActions();
   QString fileName;

 private slots:
   void newFile();
   void openFile();
   void saveFile();
   void saveFileAs();
   void saveFileAs(const QString &outputFileName);

};

endif

mainwindow.cpp

include "mainwindow.h"

include <KApplication>
include <KAction>
include <KLocale>
include <KActionCollection>
include <KStandardAction>
include <KFileDialog>
include <KMessageBox>
include <KIO/NetAccess>
include <KSaveFile>
include <QTextStream>

MainWindow::MainWindow(QWidget *parent)

   : KXmlGuiWindow(parent),
     fileName(QString())

 textArea = new KTextEdit;
 setCentralWidget(textArea);

 setupActions();

}
void MainWindow::setupActions()
{

 KAction* clearAction = new KAction(this);
 clearAction->setText(i18n("Clear"));
 clearAction->setIcon(KIcon("document-new"));
 clearAction->setShortcut(Qt::CTRL + Qt::Key_W);
 actionCollection()->addAction("clear", clearAction);
 connect(clearAction, SIGNAL(triggered(bool)),
         textArea, SLOT(clear()));

 KStandardAction::quit(kapp, 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();

}
void MainWindow::newFile()
{

 fileName.clear();
 textArea->clear();

}
void MainWindow::saveFileAs(const QString &outputFileName)
{

 KSaveFile file(outputFileName);
 file.open();
 
 QByteArray outputByteArray;
 outputByteArray.append(textArea->toPlainText());
 file.write(outputByteArray);
 file.finalize();
 file.close();
 
 fileName = outputFileName;

}
void MainWindow::saveFileAs()
{

 saveFileAs(KFileDialog::getSaveFileName());

}
void MainWindow::saveFile()
{

 if(!fileName.isEmpty())
 {
   saveFileAs(fileName);
 }
 else
 {
   saveFileAs();
 }

}
void MainWindow::openFile() //changed
{

 openFile(KFileDialog::getOpenFileName());

}
void MainWindow::openFile(const QString &inputFileName) //new
{

 QString tmpFile;
 if(KIO::NetAccess::download(inputFileName, tmpFile, 
        this))
 {
   QFile file(tmpFile);
   file.open(QIODevice::ReadOnly);
   textArea->setPlainText(QTextStream(&file).readAll());
   fileName = inputFileName;

   KIO::NetAccess::removeTempFile(tmpFile);
 }
 else
 {
   KMessageBox::error(this, 
       KIO::NetAccess::lastErrorString());
 }

}

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> This is identical to the tutorialxui.rc from the last two tutorials except tutorialx is now tutorial5.

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)

find_package(KDE4 REQUIRED) include_directories( ${KDE4_INCLUDES} )

set(tutorial5_SRCS

 main.cpp
 mainwindow.cpp

)
kde4_add_executable(tutorial5 ${tutorial5_SRCS})
target_link_libraries(tutorial5 ${KDE4_KDEUI_LIBS}

                               ${KDE4_KIO_LIBS})

install(TARGETS tutorial5 DESTINATION ${BIN_INSTALL_DIR})
install( FILES tutorial5ui.rc

        DESTINATION  ${DATA_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
$HOME/bin/tutorial5

Moving On

Now you can move on to the ### (TODO User:milliams) tutorial.