/*!
    \page pref-pane.html
    \title 7. Adding Preferences Pane
	Preferences dialog in Qt Creator is used to configure the Qt Creator settings. Since Qt Creator is just a plugin loader that
	loads all the relevant plugins, the preferences dialog shows pages that configure plugins. You can get to it by clicking
	Tools->Options.
	
	\inlineimage qtc-options-7.png
	
	
	Each plugin provides one or more options pages that get shown in the preferences dialog. In the following sub-sections
	we will learn how to add our own pages to the dialog.
	
	\section1 7.1 Core::IOptionsPage interface
	
	The Core of Qt Creator exposes an interface called \bold{Core::IOptionsPage}. The interface is defined in
	plugins/coreplugin/dialogs/ioptionspage.h.
	
	\code
    class CORE_EXPORT IOptionsPage : public QObject
    {
        Q_OBJECT
        
    public:
        IOptionsPage( *parent = 0) : QObject(parent) {}
        virtual ~IOptionsPage() {}
        virtual QString id() const = 0;
        virtual QString trName() const = 0;
        virtual QString category() const = 0;
        virtual QString trCategory() const = 0;
        virtual QWidget *createPage(QWidget *parent) = 0;
        virtual void apply() = 0;
        virtual void finish() = 0;
    };
	\endcode
	
	By implementing the above interface and exposing an instance of it, we will be able to register new pages with the
	preferences dialog.
	
	\section1 7.2 Preparing the options-page
	Let's implement a plugin that shows an options page that lists out all the open and modified files.
	
	\section2  Step 1: Implementing the "modified file" list widget
	The modified file list widget is simply a \bold{QListWidget} that shows all the modified files from the project manager. The
	class declaration is as follows
	
	\code
    #include <QListWidget>
    class ModifiedFileListWidget: public QListWidget
    {
        Q_OBJECT
        
    public:
        ModifiedFileListWidget(QWidget* parent=0);
        ~ModifiedFileListWidget();
    };
    \endcode

    Within the constructor we populate the list widget with names of the modified pages

    \code
    #include <coreplugin/filemanager.h>
    #include <coreplugin/icore.h>
    #include <coreplugin/ifile.h>

    ModifiedFileListWidget::ModifiedFileListWidget(QWidget* parent):QListWidget(parent)
    {
        // Show the list of modified pages
        Core::FileManager* fm = Core::ICore::instance()->fileManager();
        QList<Core::IFile*> files = fm->modifiedFiles();

        for(int i=0; i<files.count();i++)
        this->addItem(files.at(i)->fileName());
    }
	\endcode
	
	The destructor does nothing.
	
	\code
    ModifiedFileListerPage::~ModifiedFileListerPage()
    {

    }
	\endcode
	
	\section2 Step 2: Implementing the Core::IOptionsPage interface
	We implement the \bold {Core::IOptionsPage} interface in a class called \bold {ModifiedFileLister}. The class declaration
	is as follows
	
	\code
    #include <coreplugin/dialogs/ioptionspage.h>
    class ModifiedFileLister : public Core::IOptionsPage
    {
        Q_OBJECT

    public:
        ModifiedFileLister(QObject *parent = 0);
        ~ModifiedFileLister();
        // IOptionsPage implementation
        QString id() const;
        QString trName() const;
        QString category() const;
        QString trCategory() const;
        QWidget *createPage(QWidget *parent);
        void apply();
        void finish();
    };
	\endcode
	
	The constructor and destructor are straightforward and easy to understand.
	
	\code
    ModifiedFileLister::ModifiedFileLister(QObject *parent): IOptionsPage(parent)
    {

    }

    ModifiedFileLister::~ModifiedFileLister()
    {

    }
   	\endcode
	
	The \bold{id()} method should be implemented to return a unique identifier for the options page provided by this class. The
	string will be used internally to \underline{\bold{id}}entify the page.
	
	\code
    QString ModifiedFileLister::id() const
    {
        return "ModifiedFiles";
    }
	\endcode
	
	The \bold {trName()} method should be implemented to return a translated string name that will be shown in the options
	dialog.
	
	\code
    QString ModifiedFileLister::trName() const
    {
        return tr("Modified Files");
    }
	\endcode
	
	The \bold{category()} and \bold{trCategory()} methods should be implemented to return the group under which we want to
	show the page. The latter returns the translated version of the string returned by the former.
	
	\code
    QString ModifiedFileLister::category() const
    {
        return "Help";
    }

    QString ModifiedFileLister::trCategory() const
    {
        return tr("Help");
    }
	\endcode
	
	The \bold{createPage()} method should be implemented to return a new instance of the page implemented in step 1.
	
	\code
    QWidget *ModifiedFileLister::createPage(QWidget *parent)
    {
        return new ModifiedFileListWidget(parent);
    }
	\endcode
	
	The methods \bold {apply()} and \bold {finish()} can be implemented to accept the changes made by the user made on the
	page. In our case we don't have any changes to accept, so we leave the methods empty.
	
	\code
    void ModifiedFileLister::apply()
    {
        // Do nothing
    }

    void ModifiedFileLister::finish()
    {
        // Do nothing
    }
	\endcode
	
	\section2 Step 3: Implementing the modified-file-lister plugin
	
	We implement the plugin class similar to the \bold {DoNothingPlugin} class described in Chapter 2. Hence, we only
	describe the implementation of the initialize method of the \bold {ModifiedFileListerPlugin} class here.
	
	\code
    bool ModifiedFileListerPlugin::initialize(const QStringList& args, QString *errMsg)
    {
        Q_UNUSED(args);
        Q_UNUSED(errMsg);
        addAutoReleasedObject(new ModifiedFileLister);
        return true;
    }
	\endcode
	
	\section2 Step 4: Testing the plugin
	Upon compiling the plugin and restarting Qt Creator, we can notice in the options dialog the newly added "Modified
	Files" page.
	
	
	\inlineimage  qtc-testplugin-7.png
	
    */