Development/Tutorials/Kate/KTextEditor Example

Abstract

We build a small application using KTexteditor. This example supports syntax highlighting and other useful features. We see how to use KTextEditor.

The Code

main.cpp

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#include <KApplication>
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#include <KAboutData>
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#include <KCmdLineArgs>
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#include "mainwindow.h"
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```
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int main (int argc, char *argv[])
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```
{
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  KAboutData aboutData( "editor", "editor",

```
      ki18n("Editor"), "1.0",
```

      ki18n("A simple text area which can load and save."),

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      KAboutData::License_GPL,
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      ki18n("Copyright (c) 2007 Developer") );

  KCmdLineArgs::init( argc, argv, &aboutData );

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  KApplication app;
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```
 
```

  MainWindow* window = new MainWindow();

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  window->show();
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  return app.exec();
```
```
}
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```
</code>
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```
 
```

In <tt>main.cpp</tt> just defines ''aboutData'' and ''app'' and shows ''Mainwindow''.

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===mainwindow.h===
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<syntaxhighlight lang="cpp-qt" line>
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#ifndef MAINWINDOW_H
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#define MAINWINDOW_H
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#include <KParts/MainWindow>
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```
#include <QtGui/QKeyEvent>
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```
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namespace KTextEditor
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{
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  class Document;
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  class View;
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}
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class MainWindow : public KParts::MainWindow

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{
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  Q_OBJECT
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  public:
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```
    MainWindow(QWidget *parent=0);
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```
  private slots:
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    void clear();
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    void openFile();
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  private:
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    void setupActions();
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    KTextEditor::View *m_view;
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    KTextEditor::Document *m_doc;
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};
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#endif
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</code>
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```

Class MainWindow is a successor of KXmlGuiWindow and contains KTextEditor (document and view) as a private Variable. There are also some useful methods defined.

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```
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===mainwindow.cpp===
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<syntaxhighlight lang="cpp-qt" line>
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```
#include "mainwindow.h"
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```
#include <KApplication>
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#include <KAction>
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#include <KLocale>
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#include <KActionCollection>
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#include <KStandardAction>
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#include <KFileDialog>
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#include <KMessageBox>
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#include <KIO/NetAccess>
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#include <KSaveFile>
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#include <QTextStream>
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#include <KXMLGUIFactory>
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#include <KTextEditor/Document>
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#include <KTextEditor/View>
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#include <KTextEditor/Editor>
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#include <KTextEditor/EditorChooser>
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MainWindow::MainWindow(QWidget *)
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{
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  KTextEditor::Editor *editor = KTextEditor::EditorChooser::editor();

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```
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  if (!editor) {
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    KMessageBox::error(this, i18n("A KDE text-editor component could not be found;\n"

				  "please check your KDE installation."));

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    kapp->exit(1);
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  }
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```
 
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  m_doc = editor->createDocument(0);
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  m_view = qobject_cast<KTextEditor::View*>(m_doc->createView(this));

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  setCentralWidget(m_view);
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  setupActions();
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  setXMLFile("editorui.rc");
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  createShellGUI(true);
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  guiFactory()->addClient(m_view);
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  show ();
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}
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void MainWindow::setupActions()
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{
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  KStandardAction::quit(kapp, SLOT(quit()), actionCollection());

  KStandardAction::open(this, SLOT(openFile()), actionCollection());

  KStandardAction::clear(this, SLOT(clear()), actionCollection());

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}
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void MainWindow::clear()
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{
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  m_doc->clear();
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}
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void MainWindow::openFile()
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{
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  m_view->document()->openUrl(KFileDialog::getOpenFileName());

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}
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</code>
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The implementation is straight forward and self-explanatory. Some remarks:

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```
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'''MainWindow::Mainwindow()'''
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First the editor component is created on the heap. After creating ''document()'' and ''view()'', the GUI definitions are loaded from editorui.rc. The call ''guiFactory()->addClient(m_view)'' adds the kate parts menue and toolbar definitions to MainWindow. After that a full featured texteditor with syntax highlighting etc. is available for  your application.

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'''MainWindow::setupAction()''' defines three additional actions.

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```
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===editorui.rc===
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<code xml n>
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<!DOCTYPE kpartgui SYSTEM "kpartgui.dtd">

<kpartgui name="editor" version="1"> <!-- increase version number if you don't see changes after experimenting with this file -->

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```
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<MenuBar>
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  <Menu name="file" noMerge="1"><text>&amp;File</text>

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    <Action name="file_open" />
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    <DefineGroup name="save_merge" append="save_merge" />

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    <Separator/>
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    <DefineGroup name="revert_merge" append="revert_merge"/>

    <DefineGroup name="print_merge" append="print_merge"/>

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    <Separator/>
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    <Action name="file_quit"/>
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  </Menu>
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  <Merge />
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</MenuBar>
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<ToolBar name="mainToolBar" noMerge="1"><text>Main Toolbar</text>

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  <Action name="file_open" />
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  <DefineGroup name="file_operations" />

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  <Separator />
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  <DefineGroup name="print_merge" />
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  <Separator />
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  <Action name="file_close" />
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  <Separator />
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  <DefineGroup name="edit_operations" />

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  <Separator />
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  <DefineGroup name="find_operations" />

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  <Separator />
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  <DefineGroup name="zoom_operations" />

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</ToolBar>
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<Menu name="ktexteditor_popup" noMerge="1">

  <DefineGroup name="popup_operations" />

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</Menu>
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</kpartgui>
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</code>
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===CMakeLists.txt===
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<code ini n>
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project(editor)
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find_package(KDE4 REQUIRED)
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include_directories(${KDE4_INCLUDES})
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set(editor_SRCS 
```
```
  main.cpp
```
```
  mainwindow.cpp
```
```
)
```
```
 
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kde4_add_executable(editor ${editor_SRCS})

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target_link_libraries(editor ${KDE4_KDEUI_LIBS}

                             ${KDE4_KIO_LIBS}

                             ${KDE4_KTEXTEDITOR_LIBS})

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install(TARGETS editor DESTINATION ${BIN_INSTALL_DIR})

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install(FILES editorui.rc 
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        DESTINATION ${DATA_INSTALL_DIR}/editor)

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</code>
```