Development/Tutorials/Using KActions: Difference between revisions

    From KDE TechBase
    (Proofreading. Remove all the crap that's been added over time to make the article more focused.)
    Line 49: Line 49:
    }
    }
    </code>
    </code>
    This time, very little has changed in <tt>main.cpp</tt>, only the KAboutData constructor has been updated to show that we are now on tutorial 3.


    ===mainwindow.h===
    ===mainwindow.h===
    Line 70: Line 71:
    #endif
    #endif
    </code>
    </code>
    Only a function <tt>void setupActions()</tt> has been added which will do all the work setting up the KActions.


    ===mainwindow.cpp===
    ===mainwindow.cpp===
    Line 95: Line 97:
       clearAction->setText(i18n("Clear"));
       clearAction->setText(i18n("Clear"));
       clearAction->setIcon(KIcon("document-new"));
       clearAction->setIcon(KIcon("document-new"));
       clearAction->setShortcut(Qt::CTRL+Qt::Key_W);
       clearAction->setShortcut(Qt::CTRL + Qt::Key_W);
       actionCollection()->addAction("clear", clearAction);
       actionCollection()->addAction("clear", clearAction);
       connect(clearAction, SIGNAL(triggered(bool)),
       connect(clearAction, SIGNAL(triggered(bool)),
    Line 108: Line 110:


    ==Explanation==
    ==Explanation==
    This builds upon the KXmlGuiWindow code from [[Development/Tutorials/Using_KXmlGuiWindow|Tutorial 2]]. Most of the changes are to <tt>mainwindow.cpp</tt>, an important structural change being that the constructor for MainWindow now calls <tt>setupActions()</tt> instead of <tt>setupGUI()</tt>. <tt>setupActions()</tt> is where the new KAction code goes before finally calling <tt>setupGUI()</tt>.
    This builds upon the KXmlGuiWindow code from [[Development/Tutorials/Using_KXmlGuiWindow|Tutorial 2]]. Most of the changes are to <tt>mainwindow.cpp</tt>, an important structural change being that the constructor for MainWindow now calls <tt>setupActions()</tt> instead of <tt>setupGUI()</tt>. <tt>setupActions()</tt> is where the new KAction code goes before finally calling <tt>setupGUI()</tt> itself.


    ===Creating the KAction object===
    ===Creating the KAction object===
    Line 123: Line 125:
    Now we have our KAction object, we can start setting its properties. The following code sets the text that will be displayed in the menu and under the <tt>KAction</tt>'s icon in the toolbar.
    Now we have our KAction object, we can start setting its properties. The following code sets the text that will be displayed in the menu and under the <tt>KAction</tt>'s icon in the toolbar.
    <code cppqt>clearAction->setText(i18n("Clear"));</code>
    <code cppqt>clearAction->setText(i18n("Clear"));</code>
    Note that the text is passed through the i18n() function; this is necessary for the UI to be translatable.
    Note that the text is passed through the i18n() function; this is necessary for the UI to be translatable (more information on this can be found in the [[Development/Tutorials/Localization/i18n|i18n tutorial]]).


    ====Icon====
    ====Icon====
    Line 131: Line 133:
    ====Keyboard Shortcut====
    ====Keyboard Shortcut====
    Setting a keyboard shortcut to perform our action is equally simple:
    Setting a keyboard shortcut to perform our action is equally simple:
    <code cppqt>clearAction->setShortcut(Qt::CTRL+Qt::Key_W);</code>
    <code cppqt>clearAction->setShortcut(Qt::CTRL + Qt::Key_W);</code>
    This associates Ctrl+W with the KAction.
    This associates Ctrl+W with the KAction.


    ===Adding to the Collection===
    ===Adding to the Collection===
    In order for the action to be accessed by the XmlGui framework (explained in depth later) it must be added to the application's ''action collection''. The ''action collection'' is accessed via the <tt>actionCollection()</tt> function thusly:  
    In order for the action to be accessed by the XMLGUI framework (explained in depth later) it must be added to the application's ''action collection''. The action collection is accessed via the <tt>actionCollection()</tt> function like this:  
    <code cppqt>
    <code cppqt>
    actionCollection()->addAction("clear", clearAction);
    actionCollection()->addAction("clear", clearAction);
    </code>
    </code>
    Here, the <tt>clearAction</tt> KAction is added to the collection and given a name of ''clear''. This name (''clear'') is used by the XmlGui framework to refer to the action.
    Here, the <tt>clearAction</tt> KAction is added to the collection and given a name of ''clear''. This name (''clear'') is used by the XMLGUI framework to refer to the action.


    ====Connecting the action====
    ====Connecting the action====
    Now that the action is fully set up, it needs to be connected to something useful. In this case (because we want to clear the text area), we connect our action to the <tt>clear()</tt> action belonging to a KTextArea (which, unsurprisingly, clears the KTextArea).
    Now that the action is fully set up, it needs to be connected to something useful. In this case (because we want to clear the text area), we connect our action to the <tt>clear()</tt> action belonging to a KTextEdit (which, unsurprisingly, clears the KTextEdit)
    <code cppqt>
    <code cppqt>
    connect( clearAction, SIGNAL( triggered(bool) ),  
    connect( clearAction, SIGNAL( triggered(bool) ),  
    Line 158: Line 160:


    ==Adding the action to menus and toolbars==
    ==Adding the action to menus and toolbars==
    At the moment, the new "Clear" action has been created but it hasn't been associated with any menus or toolbars. This is done with a KDE technology called XmlGUI, which does nice things like movable toolbars for you.
    At the moment, the new "Clear" action has been created but it hasn't been associated with any menus or toolbars. This is done with a KDE technology called XMLGUI, which does nice things like movable toolbars for you.


    {{note|In a later version of KDE4, XmlGui may be replaced with a new framework called liveui. For now, XmlGui is the only and correct way to set up the UI.}}
    {{note|In a later version of KDE4, XMLGUI, may be replaced with a new framework called liveui. For now, XMLGUI, is the only and correct way to set up the UI.}}


    ==XmlGui==
    ==XMLGUI==


    The <tt>setupGUI()</tt> function in {{class|KXmlGuiWindow}} depends on the XmlGui system to construct the GUI, which XmlGui does by parsing an XML file description of the interface.
    The <tt>setupGUI()</tt> function in {{class|KXmlGuiWindow}} depends on the XMLGUI system to construct the GUI, which XMLGUI does by parsing an XML file description of the interface.


    The rule for naming this XML file is <tt>appnameui.rc</tt>, where <tt>appname</tt> is the name you set in {{class|KAboutData}} (in this case, ''tutorial3''). So in our example, the file is called <tt>tutorial3ui.rc</tt>, and is located in the build directory. Where the file will ultimately be placed is handled by CMake.
    The rule for naming this XML file is <tt>appnameui.rc</tt>, where <tt>appname</tt> is the name you set in {{class|KAboutData}} (in this case, ''tutorial3''). So in our example, the file is called <tt>tutorial3ui.rc</tt>, and is located in the build directory. Where the file will ultimately be placed is handled by CMake.
    Line 170: Line 172:
    ==''appname''ui.rc File==
    ==''appname''ui.rc File==


    Since the description of the UI is defined with XML, the layout must follow strict rules. This tutorial will not go into great depth on this topic, but for more information, see the _detailed_XmlGui_page_ (link pending).
    Since the description of the UI is defined with XML, the layout must follow strict rules. This tutorial will not go into great depth on this topic, but for more information, see the [[Development/Architecture/KDE4/XMLGUI_Technology|detailed XMLGUI page]].


    ===tutorial3ui.rc===
    ===tutorial3ui.rc===
    Line 177: Line 179:
    <!DOCTYPE kpartgui SYSTEM "kpartgui.dtd">
    <!DOCTYPE kpartgui SYSTEM "kpartgui.dtd">
    <gui name="tutorial3" version="1">
    <gui name="tutorial3" version="1">
       <ToolBar name="mainToolBar" >
       <ToolBar name="mainToolBar" >
         <text>Main Toolbar</text>
         <text>Main Toolbar</text>
         <Action name="clear" />
         <Action name="clear" />
        <ActionList name="dynamicActionlist" />
       </ToolBar>
       </ToolBar>
       <MenuBar>
       <MenuBar>
         <Menu name="file" >
         <Menu name="file" >
          <text>&amp;File</text>
           <Action name="clear" />
           <Action name="clear" />
         </Menu>
         </Menu>
    Line 196: Line 195:
    Besides having the action in the toolbar, it can also be added to the menubar. Here the action is being added to the ''File'' menu of the <tt>MenuBar</tt> the same way it was added to the toolbar.
    Besides having the action in the toolbar, it can also be added to the menubar. Here the action is being added to the ''File'' menu of the <tt>MenuBar</tt> the same way it was added to the toolbar.


    Note that you can also add dynamic action lists to your configuration file using a <tt><ActionList></tt> tag. For more information about this, see the <tt>plugActionList()</tt> method of the {{class|KXMLGUIClient}} documentation.
    Change the 'version' attribute of the <tt><nowiki><gui></nowiki></tt> tag if you changed .rc file since the last install to force a system cache update.
     
    Change the 'version' attribute of the gui tag if you changed .rc file since the last install to force a system cache update.


    ==CMake==
    ==CMake==
    Line 228: Line 225:
    If you don't have write access to where your KDE4 installation directory, you can install it to a folder in your home directory.
    If you don't have write access to where your KDE4 installation directory, you can install it to a folder in your home directory.


    To tell CMake where to install the program, set the <tt>DCMAKE_INSTALL_PREFIX</tt> switch. For example, to install the program to the KDE directory:
    To tell CMake where to install the program, set the <tt>DCMAKE_INSTALL_PREFIX</tt> switch. You probably just want to install it somewhere local for testing (it's probably a bit silly to go to the effort of installing these tutorials to your KDE directory), so the following might be appropriate:
      cmake . -DCMAKE_INSTALL_PREFIX=$KDEDIR
    mkdir build && cd build
      cmake .. -DCMAKE_INSTALL_PREFIX=$HOME
      make install
      make install
      tutorial3
      $HOME/bin/tutorial3
    Though, if you just want to install it somewhere local for testing (it's probably a bit silly to go to the effort of installing these tutorials to your KDE directory), the following might be more appropriate:
    which will create a KDE-like directory structure in your user's home directory directory and will install the executable to {{path|$HOME/bin/tutorial3}}.
    cmake . -DCMAKE_INSTALL_PREFIX=$PWD
    which will create a KDE-like directory structure under the current directory and will install the executable to {{path|$PWD/bin/tutorial3}}.


    ==Moving On==
    ==Moving On==

    Revision as of 22:52, 25 December 2007


    Development/Tutorials/Using_KActions


    How To Use KActions and XmlGui
    Tutorial Series   Beginner Tutorial
    Previous   Tutorial 2 - KXmlGuiWindow, Basic XML knowledge
    What's Next   TODO (milliams)
    Further Reading   None

    Abstract

    This tutorial introduces the concept of actions. Actions are a unified way of supplying the user with ways to interact with your program.

    For example, if we wanted to let the user of Tutorial 2 clear the text box by clicking a button in the toolbar, from an option in the File menu or through a keyboard shortcut, it could all be done with one KAction.

    KAction

    A KAction is an object which contains all the information about the icon and shortcuts that is associated with a certain action. The action is then connected to a slot which carries out the work of your action.

    The Code

    main.cpp

    1. include <KApplication>
    2. include <KAboutData>
    3. include <KCmdLineArgs>
    1. include "mainwindow.h"

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

     KAboutData aboutData( "tutorial3", "tutorial3",
         ki18n("Tutorial 3"), "1.0",
         ki18n("A simple text area using KAction etc."),
         KAboutData::License_GPL,
         ki18n("Copyright (c) 2007 Developer") );
     KCmdLineArgs::init( argc, argv, &aboutData );
     KApplication app;
    
     MainWindow* window = new MainWindow();
     window->show();
     return app.exec();
    

    } This time, very little has changed in main.cpp, only the KAboutData constructor has been updated to show that we are now on tutorial 3.

    mainwindow.h

    1. ifndef MAINWINDOW_H
    2. define MAINWINDOW_H
    1. include <KXmlGuiWindow>
    2. include <KTextEdit>

    class MainWindow : public KXmlGuiWindow {

     public:
       MainWindow(QWidget *parent=0);
    
     private:
       KTextEdit* textArea;
       void setupActions();
    

    };

    1. endif

    Only a function void setupActions() has been added which will do all the work setting up the KActions.

    mainwindow.cpp

    1. include "mainwindow.h"
    1. include <KApplication>
    2. include <KAction>
    3. include <KLocale>
    4. include <KActionCollection>
    5. include <KStandardAction>

    MainWindow::MainWindow(QWidget *parent)

       : KXmlGuiWindow(parent)
    

    {

     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());
    
     setupGUI();
    

    }

    Explanation

    This builds upon the KXmlGuiWindow code from Tutorial 2. Most of the changes are to mainwindow.cpp, an important structural change being that the constructor for MainWindow now calls setupActions() instead of setupGUI(). setupActions() is where the new KAction code goes before finally calling setupGUI() itself.

    Creating the KAction object

    The KAction is built up in a number of steps. The first is including the KAction library and then creating the KAction:

    1. include <KAction>

    ... KAction* clearAction = new KAction(this); This creates a new KAction called clearAction.

    Setting KAction Properties

    Text

    Now we have our KAction object, we can start setting its properties. The following code sets the text that will be displayed in the menu and under the KAction's icon in the toolbar. clearAction->setText(i18n("Clear")); Note that the text is passed through the i18n() function; this is necessary for the UI to be translatable (more information on this can be found in the i18n tutorial).

    Icon

    If the action is going to be displayed in a toolbar, it's nice to have an icon depicting the action. The following code sets the icon to the standard KDE document-new icon through the use of the setIcon() function: clearAction->setIcon(KIcon("document-new"));

    Keyboard Shortcut

    Setting a keyboard shortcut to perform our action is equally simple: clearAction->setShortcut(Qt::CTRL + Qt::Key_W); This associates Ctrl+W with the KAction.

    Adding to the Collection

    In order for the action to be accessed by the XMLGUI framework (explained in depth later) it must be added to the application's action collection. The action collection is accessed via the actionCollection() function like this: actionCollection()->addAction("clear", clearAction); Here, the clearAction KAction is added to the collection and given a name of clear. This name (clear) is used by the XMLGUI framework to refer to the action.

    Connecting the action

    Now that the action is fully set up, it needs to be connected to something useful. In this case (because we want to clear the text area), we connect our action to the clear() action belonging to a KTextEdit (which, unsurprisingly, clears the KTextEdit) connect( clearAction, SIGNAL( triggered(bool) ),

            textArea, SLOT( clear() ) );
    

    This is the same as it would be done in Qt with a QAction.

    KStandardAction

    For actions which would likely appear in almost every KDE application such as 'quit', 'save', and 'load' there are pre-created convenience KActions, accessed through KStandardAction.

    They are very simple to use. Once the library has been included (#include <KStandardAction>), simply supply it with what you want the function to do and which KActionCollection to add it to. For example: KStandardAction::quit(kapp, SLOT(quit()), actionCollection()); This creates a KAction with the correct icon, text and shortcut and even adds it to the File menu.

    Adding the action to menus and toolbars

    At the moment, the new "Clear" action has been created but it hasn't been associated with any menus or toolbars. This is done with a KDE technology called XMLGUI, which does nice things like movable toolbars for you.

    Note
    In a later version of KDE4, XMLGUI, may be replaced with a new framework called liveui. For now, XMLGUI, is the only and correct way to set up the UI.


    XMLGUI

    The setupGUI() function in KXmlGuiWindow depends on the XMLGUI system to construct the GUI, which XMLGUI does by parsing an XML file description of the interface.

    The rule for naming this XML file is appnameui.rc, where appname is the name you set in KAboutData (in this case, tutorial3). So in our example, the file is called tutorial3ui.rc, and is located in the build directory. Where the file will ultimately be placed is handled by CMake.

    appnameui.rc File

    Since the description of the UI is defined with XML, the layout must follow strict rules. This tutorial will not go into great depth on this topic, but for more information, see the detailed XMLGUI page.

    tutorial3ui.rc

    <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE kpartgui SYSTEM "kpartgui.dtd"> <gui name="tutorial3" version="1">

     <ToolBar name="mainToolBar" >
       <text>Main Toolbar</text>
       <Action name="clear" />
     </ToolBar>
     <MenuBar>
       <Menu name="file" >
         <Action name="clear" />
       </Menu>
     </MenuBar>
    

    </gui>

    The <Toolbar> tag allows you to describe the toolbar, which is the bar across the top of the window normally with icons. Here it is given the unique name mainToolBar and its user visible name set to Main Toolbar using the <text> tag. The clear action is added to the toolbar using the <Action> tag, the name parameter in this tag being the string that was passed to the KActionCollection with addAction() in mainwindow.cpp.

    Besides having the action in the toolbar, it can also be added to the menubar. Here the action is being added to the File menu of the MenuBar the same way it was added to the toolbar.

    Change the 'version' attribute of the <gui> tag if you changed .rc file since the last install to force a system cache update.

    CMake

    Finally, the tutorial3ui.rc needs to go somewhere where KDE can find it (can't just leave it in the source directory!). This means the project needs to be installed somewhere.

    CMakeLists.txt

    project(tutorial3)

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

    set(tutorial3_SRCS

     main.cpp
     mainwindow.cpp
    

    )

    kde4_add_executable(tutorial3 ${tutorial3_SRCS})

    target_link_libraries(tutorial3 ${KDE4_KDEUI_LIBS})

    install(TARGETS tutorial3 DESTINATION ${BIN_INSTALL_DIR}) install( FILES tutorial3ui.rc

            DESTINATION  ${DATA_INSTALL_DIR}/tutorial3 )
    

    This file is almost identical to the one for tutorial2, but with two extra lines at the end that describe where the files are to be installed. Firstly, the tutorial3 target is installed to the BIN_INSTALL_DIR then the tutorial3ui.rc file that describes the layout of the user interface is installed to the application's data directory.

    Make, Install And Run

    If you don't have write access to where your KDE4 installation directory, you can install it to a folder in your home directory.

    To tell CMake where to install the program, set the DCMAKE_INSTALL_PREFIX switch. You probably just want to install it somewhere local for testing (it's probably a bit silly to go to the effort of installing these tutorials to your KDE directory), so the following might be appropriate:

    mkdir build && cd build
    cmake .. -DCMAKE_INSTALL_PREFIX=$HOME
    make install
    $HOME/bin/tutorial3
    

    which will create a KDE-like directory structure in your user's home directory directory and will install the executable to $HOME/bin/tutorial3.

    Moving On

    TODO