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# Listviews with Checkable Items

This example program shows how to use listviews with different types of checkable items.

Header file:

    /****************************************************************************
    ** $Id:  qt/checklists.h   3.0.4   edited Oct 12 2001 $
    **
    ** Copyright (C) 1992-2000 Trolltech AS.  All rights reserved.
    **
    ** This file is part of an example program for Qt.  This example
    ** program may be used, distributed and modified without limitation.
    **
    *****************************************************************************/

    #ifndef CHECKLISTS_H
    #define CHECKLISTS_H

    #include <qwidget.h>

    class QListView;
    class QLabel;

    class CheckLists : public QWidget
    {
        Q_OBJECT

    public:
        CheckLists( QWidget *parent = 0, const char *name = 0 );

    protected:
        QListView *lv1, *lv2;
        QLabel *label;

    protected slots:
        void copy1to2();
        void copy2to3();

    };

    #endif

Implementation:

    /****************************************************************************
    ** $Id:  qt/checklists.cpp   3.0.4   edited Oct 12 2001 $
    **
    ** Copyright (C) 1992-2000 Trolltech AS.  All rights reserved.
    **
    ** This file is part of an example program for Qt.  This example
    ** program may be used, distributed and modified without limitation.
    **
    *****************************************************************************/

    #include "checklists.h"

    #include <qlistview.h>
    #include <qvbox.h>
    #include <qlabel.h>
    #include <qvaluelist.h>
    #include <qstring.h>
    #include <qpushbutton.h>
    #include <qlayout.h>

    /*
     * Constructor
     *
     * Create all child widgets of the CheckList Widget
     */

    CheckLists::CheckLists( QWidget *parent, const char *name )
        : QWidget( parent, name )
    {
        QHBoxLayout *lay = new QHBoxLayout( this );
        lay->setMargin( 5 );

        // create a widget which layouts its childs in a column
        QVBoxLayout *vbox1 = new QVBoxLayout( lay );
        vbox1->setMargin( 5 );

        // First child: a Label
        vbox1->addWidget( new QLabel( "Check some items!", this ) );

        // Second child: the ListView
        lv1 = new QListView( this );
        vbox1->addWidget( lv1 );
        lv1->addColumn( "Items" );
        lv1->setRootIsDecorated( TRUE );

        // create a list with 4 ListViewItems which will be parent items of other ListViewItems
        QValueList<QListViewItem *> parentList;

        parentList.append( new QListViewItem( lv1, "Parent Item 1" ) );
        parentList.append( new QListViewItem( lv1, "Parent Item 2" ) );
        parentList.append( new QListViewItem( lv1, "Parent Item 3" ) );
        parentList.append( new QListViewItem( lv1, "Parent Item 4" ) );

        QListViewItem *item = 0;
        unsigned int num = 1;
        // go through the list of parent items...
        for ( QValueList<QListViewItem*>::Iterator it = parentList.begin(); it != parentList.end();
              ( *it )->setOpen( TRUE ), ++it, num++ ) {
            item = *it;
            // ...and create 5 checkable child ListViewItems for each parent item
            for ( unsigned int i = 1; i <= 5; i++ )
                (void)new QCheckListItem( item, QString( "%1. Child of Parent %2" ).arg( i ).arg( num ), QCheckListItem::CheckBox );
        }

        // Create another widget for layouting
        QVBoxLayout *tmp = new QVBoxLayout( lay );
        tmp->setMargin( 5 );

        // create a pushbutton
        QPushButton *copy1 = new QPushButton( "  ->  ", this );
        tmp->addWidget( copy1 );
        copy1->setMaximumWidth( copy1->sizeHint().width() );
        // connect the SIGNAL clicked() of the pushbutton with the SLOT copy1to2()
        connect( copy1, SIGNAL( clicked() ), this, SLOT( copy1to2() ) );

        // another widget for layouting
        QVBoxLayout *vbox2 = new QVBoxLayout( lay );
        vbox2->setMargin( 5 );

        // and another label
        vbox2->addWidget( new QLabel( "Check one item!", this ) );

        // create the second listview
        lv2 = new QListView( this );
        vbox2->addWidget( lv2 );
        lv2->addColumn( "Items" );
        lv2->setRootIsDecorated( TRUE );

        // another widget needed for layouting only
        tmp = new QVBoxLayout( lay );
        tmp->setMargin( 5 );

        // create another pushbutton...
        QPushButton *copy2 = new QPushButton( "  ->  ", this );
        lay->addWidget( copy2 );
        copy2->setMaximumWidth( copy2->sizeHint().width() );
        // ...and connect its clicked() SIGNAL to the copy2to3() SLOT
        connect( copy2, SIGNAL( clicked() ), this, SLOT( copy2to3() ) );

        tmp = new QVBoxLayout( lay );
        tmp->setMargin( 5 );

        // and create a label which will be at the right of the window
        label = new QLabel( "No Item yet...", this );
        tmp->addWidget( label );
    }

    /*
     * SLOT copy1to2()
     *
     * Copies all checked ListViewItems from the first ListView to
     * the second one, and inserts them as Radio-ListViewItem.
     */

    void CheckLists::copy1to2()
    {
        // create an iterator which operates on the first ListView
        QListViewItemIterator it( lv1 );

        lv2->clear();

        // Insert first a controller Item into the second ListView. Always if Radio-ListViewItems
        // are inserted into a Listview, the parent item of these MUST be a controller Item!
        QCheckListItem *item = new QCheckListItem( lv2, "Controller", QCheckListItem::Controller );
        item->setOpen( TRUE );

        // iterate through the first ListView...
        for ( ; it.current(); ++it )
            // ...check state of childs, and...
            if ( it.current()->parent() )
                // ...if the item is checked...
                if ( ( (QCheckListItem*)it.current() )->isOn() )
                    // ...insert a Radio-ListViewItem with the same text into the second ListView
                    (void)new QCheckListItem( item, it.current()->text( 0 ), QCheckListItem::RadioButton );

        if ( item->firstChild() )
            ( ( QCheckListItem* )item->firstChild() )->setOn( TRUE );
    }

    /*
     * SLOT copy2to3()
     *
     * Copies the checked item of the second ListView into the
     * Label at the right.
     */

    void CheckLists::copy2to3()
    {
        // create an iterator which operates on the second ListView
        QListViewItemIterator it( lv2 );

        label->setText( "No Item checked" );

        // iterate through the second ListView...
        for ( ; it.current(); ++it )
            // ...check state of childs, and...
            if ( it.current()->parent() )
                // ...if the item is checked...
                if ( ( (QCheckListItem*)it.current() )->isOn() )
                    // ...set the text of the item to the label
                    label->setText( it.current()->text( 0 ) );
    }

Main:

    /****************************************************************************
    ** $Id:  qt/main.cpp   3.0.4   edited Oct 12 2001 $
    **
    ** Copyright (C) 1992-2000 Trolltech AS.  All rights reserved.
    **
    ** This file is part of an example program for Qt.  This example
    ** program may be used, distributed and modified without limitation.
    **
    *****************************************************************************/

    #include "checklists.h"
    #include <qapplication.h>

    int main( int argc, char **argv )
    {
        QApplication a( argc, argv );

        CheckLists checklists;
        checklists.resize( 650, 350 );
        checklists.setCaption( "Qt Example - CheckLists" );
        a.setMainWidget( &checklists );
        checklists.show();

        return a.exec();
    }

See also Examples.