QDialog

NAME

SYNOPSIS

Inherits QWidget.

Inherited by QColorDialog, QErrorMessage, QFileDialog, QFontDialog, QInputDialog, QMessageBox, QMotifDialog, QProgressDialog, QTabDialog, and QWizard.

Public Members

Public Slots

Properties

Protected Members

Protected Slots

DESCRIPTION

A dialog window is a top-level window mostly used for short-term tasks and brief communications with the user. QDialogs may be modal or modeless. QDialogs support extensibility and can provide a return value. They can have default buttons. QDialogs can also have a QSizeGrip in their lower-right corner, using setSizeGripEnabled().

Note that QDialog uses the parent widget slightly differently from other classes in Qt. A dialog is always a top-level widget, but if it has a parent, its default location is centered on top of the parent's top-level widget (if it is not top-level itself). It will also share the parent's taskbar entry.  

Modal Dialogs

The most common way to display a modal dialog is to call its exec() function. When the user closes the dialog, exec() will provide a useful return value. Typically we connect a default button, e.g. "OK", to the accept() slot and a" Cancel" button to the reject() slot, to get the dialog to close and return the appropriate value. Alternatively you can connect to the done() slot, passing it Accepted or Rejected.

An alternative is to call setModal(TRUE), then show(). Unlike exec(), show() returns control to the caller immediately. Calling setModal(TRUE) is especially useful for progress dialogs, where the user must have the ability to interact with the dialog, e.g. to cancel a long running operation. If you use show() and setModal(TRUE) together you must call QApplication::processEvents() periodically during processing to enable the user to interact with the dialog. (See QProgressDialog.)  

Modeless Dialogs

Modeless dialogs are displayed using show(), which returns control to the caller immediately.  

Default button

Escape Key

Extensibility

Return value (modal dialogs)

Examples

        QFileDialog *dlg = new QFileDialog( workingDirectory,


                QString::null, 0, 0, TRUE );


        dlg->setCaption( QFileDialog::tr( "Open" ) );


        dlg->setMode( QFileDialog::ExistingFile );


        QString result;


        if ( dlg->exec() == QDialog::Accepted ) {


            result = dlg->selectedFile();


            workingDirectory = dlg->url();


        }


        delete dlg;


        return result;

A modeless dialog. After the show() call, control returns to the main event loop.

    int main( int argc, char **argv )


    {


        QApplication a( argc, argv );

        int scale = 10;

        LifeDialog *life = new LifeDialog( scale );


        a.setMainWidget( life );


        life->setCaption("Qt Example - Life");


        life->show();

        return a.exec();


    }

See also QTabDialog, QWidget, QProgressDialog, GUI Design Handbook: Dialogs, Standard, Abstract Widget Classes, and Dialog Classes.  

Member Type Documentation

QDialog::DialogCode

QDialog::Accepted

QDialog::Rejected

MEMBER FUNCTION DOCUMENTATION

explicit QDialog::QDialog ( QWidget * parent = 0, const char * name = 0, bool modal = FALSE, WFlags f = 0 )

A dialog is always a top-level widget, but if it has a parent, its default location is centered on top of the parent. It will also share the parent's taskbar entry.

The widget flags f are passed on to the QWidget constructor. If, for example, you don't want a What's This button in the titlebar of the dialog, pass WStyle_Customize | WStyle_NormalBorder | WStyle_Title | WStyle_SysMenu in f.

Warning: In Qt 3.2, the modal flag is obsolete. There is now a setModal() function that can be used for obtaining a modal behavior when calling show(). This is rarely needed, because modal dialogs are usually invoked using exec(), which ignores the modal flag.

See also QWidget::setWFlags() and Qt::WidgetFlags.  

QDialog::~QDialog ()

void QDialog::accept () [virtual protected slot]

See also reject() and done().

Examples:  

void QDialog::done ( int r ) [virtual protected slot]

As with QWidget::close(), done() deletes the dialog if the WDestructiveClose flag is set. If the dialog is the application's main widget, the application terminates. If the dialog is the last window closed, the QApplication::lastWindowClosed() signal is emitted.

See also accept(), reject(), QApplication::mainWidget(), and QApplication::quit().  

int QDialog::exec () [slot]

Users cannot interact with any other window in the same application until they close the dialog.

See also show() and result().

Examples:  

QWidget * QDialog::extension () const

See also setExtension().  

bool QDialog::isModal () const

bool QDialog::isSizeGripEnabled () const

Orientation QDialog::orientation () const

See also setOrientation().  

void QDialog::reject () [virtual protected slot]

See also accept() and done().  

int QDialog::result () const

Do not call this function if the dialog was constructed with the WDestructiveClose flag.  

void QDialog::setExtension ( QWidget * extension )

This function must only be called while the dialog is hidden.

See also showExtension(), setOrientation(), and extension().  

void QDialog::setModal ( bool modal )

void QDialog::setOrientation ( Orientation orientation )

See also orientation() and setExtension().  

void QDialog::setResult ( int i ) [protected]

void QDialog::setSizeGripEnabled ( bool )

void QDialog::show () [virtual]

The dialog will be modal or modeless according to the value of the modal property.

See also exec() and modal.

Examples:

Reimplemented from QWidget.  

void QDialog::showExtension ( bool showIt ) [protected slot]

This slot is usually connected to the QButton::toggled() signal of a QPushButton.

A dialog with a visible extension is not resizeable.

See also show(), setExtension(), and setOrientation().  

Property Documentation

bool modal

By default, this property is false and show() pops up the dialog as modeless.

exec() ignores the value of this property and always pops up the dialog as modal.

See also show() and exec().

Set this property's value with setModal() and get this property's value with isModal().  

bool sizeGripEnabled

A QSizeGrip is placed in the bottom right corner of the dialog when this property is enabled. By default, the size grip is disabled.

Set this property's value with setSizeGripEnabled() and get this property's value with isSizeGripEnabled().

SEE ALSO

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