QMessageBox Class

The QMessageBox class provides a modal dialog for informing the user or for asking the user a question and receiving an answer. More...

Header:	#include <QMessageBox>
qmake:	QT += widgets
Inherits:	QDialog

• List of all members, including inherited members
• Obsolete members

Public Types

enum	ButtonRole { InvalidRole, AcceptRole, RejectRole, DestructiveRole, ActionRole, …, ResetRole }
enum	Icon { NoIcon, Question, Information, Warning, Critical }
enum	StandardButton { Ok, Open, Save, Cancel, Close, …, ButtonMask }
flags	StandardButtons

Properties

detailedText : QString icon : Icon iconPixmap : QPixmap informativeText : QString

standardButtons : StandardButtons text : QString textFormat : Qt::TextFormat textInteractionFlags : Qt::TextInteractionFlags

Public Functions

	QMessageBox(QMessageBox::Icon icon, const QString &title, const QString &text, QMessageBox::StandardButtons buttons = NoButton, QWidget *parent = nullptr, Qt::WindowFlags f = Qt::Dialog | Qt::MSWindowsFixedSizeDialogHint)
	QMessageBox(QWidget *parent = nullptr)
virtual	~QMessageBox()
void	addButton(QAbstractButton *button, QMessageBox::ButtonRole role)
QPushButton *	addButton(const QString &text, QMessageBox::ButtonRole role)
QPushButton *	addButton(QMessageBox::StandardButton button)
QAbstractButton *	button(QMessageBox::StandardButton which) const
QMessageBox::ButtonRole	buttonRole(QAbstractButton *button) const
QList<QAbstractButton *>	buttons() const
QCheckBox *	checkBox() const
QAbstractButton *	clickedButton() const
QPushButton *	defaultButton() const
QString	detailedText() const
QAbstractButton *	escapeButton() const
QMessageBox::Icon	icon() const
QPixmap	iconPixmap() const
QString	informativeText() const
void	open(QObject *receiver, const char *member)
void	removeButton(QAbstractButton *button)
void	setCheckBox(QCheckBox *cb)
void	setDefaultButton(QPushButton *button)
void	setDefaultButton(QMessageBox::StandardButton button)
void	setDetailedText(const QString &text)
void	setEscapeButton(QAbstractButton *button)
void	setEscapeButton(QMessageBox::StandardButton button)
void	setIcon(QMessageBox::Icon)
void	setIconPixmap(const QPixmap &pixmap)
void	setInformativeText(const QString &text)
void	setStandardButtons(QMessageBox::StandardButtons buttons)
void	setText(const QString &text)
void	setTextFormat(Qt::TextFormat format)
void	setTextInteractionFlags(Qt::TextInteractionFlags flags)
void	setWindowModality(Qt::WindowModality windowModality)
void	setWindowTitle(const QString &title)
QMessageBox::StandardButton	standardButton(QAbstractButton *button) const
QMessageBox::StandardButtons	standardButtons() const
QString	text() const
Qt::TextFormat	textFormat() const
Qt::TextInteractionFlags	textInteractionFlags() const

Public Slots

virtual int

exec() override

Signals

void	buttonClicked(QAbstractButton *button)

Static Public Members

void	about(QWidget *parent, const QString &title, const QString &text)
void	aboutQt(QWidget *parent, const QString &title = QString())
QMessageBox::StandardButton	critical(QWidget *parent, const QString &title, const QString &text, QMessageBox::StandardButtons buttons = Ok, QMessageBox::StandardButton defaultButton = NoButton)
QMessageBox::StandardButton	information(QWidget *parent, const QString &title, const QString &text, QMessageBox::StandardButtons buttons = Ok, QMessageBox::StandardButton defaultButton = NoButton)
QMessageBox::StandardButton	question(QWidget *parent, const QString &title, const QString &text, QMessageBox::StandardButtons buttons = StandardButtons(Yes | No), QMessageBox::StandardButton defaultButton = NoButton)
QMessageBox::StandardButton	warning(QWidget *parent, const QString &title, const QString &text, QMessageBox::StandardButtons buttons = Ok, QMessageBox::StandardButton defaultButton = NoButton)

Reimplemented Protected Functions

virtual void	changeEvent(QEvent *ev) override
virtual void	closeEvent(QCloseEvent *e) override
virtual bool	event(QEvent *e) override
virtual void	keyPressEvent(QKeyEvent *e) override
virtual void	resizeEvent(QResizeEvent *event) override
virtual void	showEvent(QShowEvent *e) override

Detailed Description

A message box displays a primary text to alert the user to a situation, an informative text to further explain the alert or to ask the user a question, and an optional detailed text to provide even more data if the user requests it. A message box can also display an icon and standard buttons for accepting a user response.

Two APIs for using QMessageBox are provided, the property-based API, and the static functions. Calling one of the static functions is the simpler approach, but it is less flexible than using the property-based API, and the result is less informative. Using the property-based API is recommended.

The Property-based API

To use the property-based API, construct an instance of QMessageBox, set the desired properties, and call exec() to show the message. The simplest configuration is to set only the message text property.

QMessageBox msgBox;
msgBox.setText("The document has been modified.");
msgBox.exec();

The user must click the OK button to dismiss the message box. The rest of the GUI is blocked until the message box is dismissed.

A better approach than just alerting the user to an event is to also ask the user what to do about it. Store the question in the informative text property, and set the standard buttons property to the set of buttons you want as the set of user responses. The buttons are specified by combining values from StandardButtons using the bitwise OR operator. The display order for the buttons is platform-dependent. For example, on Windows, Save is displayed to the left of Cancel, whereas on Mac OS, the order is reversed.

Mark one of your standard buttons to be your default button.

QMessageBox msgBox;
msgBox.setText("The document has been modified.");
msgBox.setInformativeText("Do you want to save your changes?");
msgBox.setStandardButtons(QMessageBox::Save | QMessageBox::Discard | QMessageBox::Cancel);
msgBox.setDefaultButton(QMessageBox::Save);
int ret = msgBox.exec();

This is the approach recommended in the macOS Guidelines. Similar guidelines apply for the other platforms, but note the different ways the informative text is handled for different platforms.

The exec() slot returns the StandardButtons value of the button that was clicked.

switch (ret) {
  case QMessageBox::Save:
      // Save was clicked
      break;
  case QMessageBox::Discard:
      // Don't Save was clicked
      break;
  case QMessageBox::Cancel:
      // Cancel was clicked
      break;
  default:
      // should never be reached
      break;
}

To give the user more information to help him answer the question, set the detailed text property. If the detailed text property is set, the Show Details... button will be shown.

Clicking the Show Details... button displays the detailed text.

Rich Text and the Text Format Property

The detailed text property is always interpreted as plain text. The main text and informative text properties can be either plain text or rich text. These strings are interpreted according to the setting of the text format property. The default setting is auto-text.

Note that for some plain text strings containing XML meta-characters, the auto-text rich text detection test may fail causing your plain text string to be interpreted incorrectly as rich text. In these rare cases, use Qt::convertFromPlainText() to convert your plain text string to a visually equivalent rich text string, or set the text format property explicitly with setTextFormat().

Severity Levels and the Icon and Pixmap Properties

QMessageBox supports four predefined message severity levels, or message types, which really only differ in the predefined icon they each show. Specify one of the four predefined message types by setting the icon property to one of the predefined icons. The following rules are guidelines:

	Question	For asking a question during normal operations.
	Information	For reporting information about normal operations.
	Warning	For reporting non-critical errors.
	Critical	For reporting critical errors.

Predefined icons are not defined by QMessageBox, but provided by the style. The default value is No Icon. The message boxes are otherwise the same for all cases. When using a standard icon, use the one recommended in the table, or use the one recommended by the style guidelines for your platform. If none of the standard icons is right for your message box, you can use a custom icon by setting the icon pixmap property instead of setting the icon property.

In summary, to set an icon, use either setIcon() for one of the standard icons, or setIconPixmap() for a custom icon.

The Static Functions API

Building message boxes with the static functions API, although convenient, is less flexible than using the property-based API, because the static function signatures lack parameters for setting the informative text and detailed text properties. One work-around for this has been to use the title parameter as the message box main text and the text parameter as the message box informative text. Because this has the obvious drawback of making a less readable message box, platform guidelines do not recommend it. The Microsoft Windows User Interface Guidelines recommend using the application name as the window's title, which means that if you have an informative text in addition to your main text, you must concatenate it to the text parameter.

Note that the static function signatures have changed with respect to their button parameters, which are now used to set the standard buttons and the default button.

Static functions are available for creating information(), question(), warning(), and critical() message boxes.

int ret = QMessageBox::warning(this, tr("My Application"),
                               tr("The document has been modified.\n"
                                  "Do you want to save your changes?"),
                               QMessageBox::Save | QMessageBox::Discard
                               | QMessageBox::Cancel,
                               QMessageBox::Save);

The Standard Dialogs example shows how to use QMessageBox and the other built-in Qt dialogs.

Advanced Usage

If the standard buttons are not flexible enough for your message box, you can use the addButton() overload that takes a text and a ButtonRole to add custom buttons. The ButtonRole is used by QMessageBox to determine the ordering of the buttons on screen (which varies according to the platform). You can test the value of clickedButton() after calling exec(). For example,

QMessageBox msgBox;
QPushButton *connectButton = msgBox.addButton(tr("Connect"), QMessageBox::ActionRole);
QPushButton *abortButton = msgBox.addButton(QMessageBox::Abort);

msgBox.exec();

if (msgBox.clickedButton() == connectButton) {
    // connect
} else if (msgBox.clickedButton() == abortButton) {
    // abort
}

Default and Escape Keys

The default button (i.e., the button activated when Enter is pressed) can be specified using setDefaultButton(). If a default button is not specified, QMessageBox tries to find one based on the button roles of the buttons used in the message box.

The escape button (the button activated when Esc is pressed) can be specified using setEscapeButton(). If an escape button is not specified, QMessageBox tries to find one using these rules:

1. If there is only one button, it is the button activated when Esc is pressed.
2. If there is a Cancel button, it is the button activated when Esc is pressed.
3. If there is exactly one button having either the Reject role or the the No role, it is the button activated when Esc is pressed.

When an escape button can't be determined using these rules, pressing Esc has no effect.

See also QDialogButtonBox, GUI Design Handbook: Message Box, Standard Dialogs Example, and Application Example.

Member Type Documentation

enum QMessageBox::ButtonRole

This enum describes the roles that can be used to describe buttons in the button box. Combinations of these roles are as flags used to describe different aspects of their behavior.

Constant	Value	Description
QMessageBox::InvalidRole	-1	The button is invalid.
QMessageBox::AcceptRole	0	Clicking the button causes the dialog to be accepted (e.g. OK).
QMessageBox::RejectRole	1	Clicking the button causes the dialog to be rejected (e.g. Cancel).
QMessageBox::DestructiveRole	2	Clicking the button causes a destructive change (e.g. for Discarding Changes) and closes the dialog.
QMessageBox::ActionRole	3	Clicking the button causes changes to the elements within the dialog.
QMessageBox::HelpRole	4	The button can be clicked to request help.
QMessageBox::YesRole	5	The button is a "Yes"-like button.
QMessageBox::NoRole	6	The button is a "No"-like button.
QMessageBox::ApplyRole	8	The button applies current changes.
QMessageBox::ResetRole	7	The button resets the dialog's fields to default values.

See also StandardButton.

enum QMessageBox::Icon

This enum has the following values:

Constant	Value	Description
QMessageBox::NoIcon	0	the message box does not have any icon.
QMessageBox::Question	4	an icon indicating that the message is asking a question.
QMessageBox::Information	1	an icon indicating that the message is nothing out of the ordinary.
QMessageBox::Warning	2	an icon indicating that the message is a warning, but can be dealt with.
QMessageBox::Critical	3	an icon indicating that the message represents a critical problem.

enum QMessageBox::StandardButtonflags QMessageBox::StandardButtons

These enums describe flags for standard buttons. Each button has a defined ButtonRole.

Constant	Value	Description
QMessageBox::Ok	0x00000400	An "OK" button defined with the AcceptRole.
QMessageBox::Open	0x00002000	An "Open" button defined with the AcceptRole.
QMessageBox::Save	0x00000800	A "Save" button defined with the AcceptRole.
QMessageBox::Cancel	0x00400000	A "Cancel" button defined with the RejectRole.
QMessageBox::Close	0x00200000	A "Close" button defined with the RejectRole.
QMessageBox::Discard	0x00800000	A "Discard" or "Don't Save" button, depending on the platform, defined with the DestructiveRole.
QMessageBox::Apply	0x02000000	An "Apply" button defined with the ApplyRole.
QMessageBox::Reset	0x04000000	A "Reset" button defined with the ResetRole.
QMessageBox::RestoreDefaults	0x08000000	A "Restore Defaults" button defined with the ResetRole.
QMessageBox::Help	0x01000000	A "Help" button defined with the HelpRole.
QMessageBox::SaveAll	0x00001000	A "Save All" button defined with the AcceptRole.
QMessageBox::Yes	0x00004000	A "Yes" button defined with the YesRole.
QMessageBox::YesToAll	0x00008000	A "Yes to All" button defined with the YesRole.
QMessageBox::No	0x00010000	A "No" button defined with the NoRole.
QMessageBox::NoToAll	0x00020000	A "No to All" button defined with the NoRole.
QMessageBox::Abort	0x00040000	An "Abort" button defined with the RejectRole.
QMessageBox::Retry	0x00080000	A "Retry" button defined with the AcceptRole.
QMessageBox::Ignore	0x00100000	An "Ignore" button defined with the AcceptRole.
QMessageBox::NoButton	0x00000000	An invalid button.

The following values are obsolete:

Constant	Value	Description
QMessageBox::YesAll	YesToAll	Use YesToAll instead.
QMessageBox::NoAll	NoToAll	Use NoToAll instead.
QMessageBox::Default	0x00000100	Use the defaultButton argument of information(), warning(), etc. instead, or call setDefaultButton().
QMessageBox::Escape	0x00000200	Call setEscapeButton() instead.
QMessageBox::FlagMask	0x00000300
QMessageBox::ButtonMask	~FlagMask

This enum was introduced or modified in Qt 4.2.

The StandardButtons type is a typedef for QFlags<StandardButton>. It stores an OR combination of StandardButton values.

See also ButtonRole and standardButtons.

Member Function Documentation

QMessageBox::QMessageBox(QMessageBox::Icon icon, const QString &title, const QString &text, QMessageBox::StandardButtons buttons = NoButton, QWidget *parent = nullptr, Qt::WindowFlags f = Qt::Dialog | Qt::MSWindowsFixedSizeDialogHint)

Constructs a message box with the given icon, title, text, and standard buttons. Standard or custom buttons can be added at any time using addButton(). The parent and f arguments are passed to the QDialog constructor.

The message box is an application modal dialog box.

On macOS, if parent is not nullptr and you want your message box to appear as a Qt::Sheet of that parent, set the message box's window modality to Qt::WindowModal (default). Otherwise, the message box will be a standard dialog.

See also setWindowTitle(), setText(), setIcon(), and setStandardButtons().

QMessageBox::QMessageBox(QWidget *parent = nullptr)

Constructs a message box with no text and no buttons. parent is passed to the QDialog constructor.

On macOS, if you want your message box to appear as a Qt::Sheet of its parent, set the message box's window modality to Qt::WindowModal or use open(). Otherwise, the message box will be a standard dialog.

[signal] void QMessageBox::buttonClicked(QAbstractButton *button)

This signal is emitted whenever a button is clicked inside the QMessageBox. The button that was clicked in returned in button.

[override virtual slot] int QMessageBox::exec()

Reimplements: QDialog::exec().

Shows the message box as a modal dialog, blocking until the user closes it.

When using a QMessageBox with standard buttons, this function returns a StandardButton value indicating the standard button that was clicked. When using QMessageBox with custom buttons, this function returns an opaque value; use clickedButton() to determine which button was clicked.

Note: The result() function returns also StandardButton value instead of QDialog::DialogCode.

Users cannot interact with any other window in the same application until they close the dialog, either by clicking a button or by using a mechanism provided by the window system.

See also show() and result().

[virtual] QMessageBox::~QMessageBox()

Destroys the message box.

[static] void QMessageBox::about(QWidget *parent, const QString &title, const QString &text)

Displays a simple about box with title title and text text. The about box's parent is parent.

about() looks for a suitable icon in four locations:

1. It prefers parent->icon() if that exists.
2. If not, it tries the top-level widget containing parent.
3. If that fails, it tries the active window.
4. As a last resort it uses the Information icon.

The about box has a single button labelled "OK". On macOS, the about box is popped up as a modeless window; on other platforms, it is currently application modal.

See also QWidget::windowIcon() and QApplication::activeWindow().

[static] void QMessageBox::aboutQt(QWidget *parent, const QString &title = QString())

Displays a simple message box about Qt, with the given title and centered over parent (if parent is not nullptr). The message includes the version number of Qt being used by the application.

This is useful for inclusion in the Help menu of an application, as shown in the Menus example.

QApplication provides this functionality as a slot.

On macOS, the about box is popped up as a modeless window; on other platforms, it is currently application modal.

See also QApplication::aboutQt().

void QMessageBox::addButton(QAbstractButton *button, QMessageBox::ButtonRole role)

Adds the given button to the message box with the specified role.

This function was introduced in Qt 4.2.

See also removeButton(), button(), and setStandardButtons().

QPushButton *QMessageBox::addButton(const QString &text, QMessageBox::ButtonRole role)

This is an overloaded function.

Creates a button with the given text, adds it to the message box for the specified role, and returns it.

This function was introduced in Qt 4.2.

QPushButton *QMessageBox::addButton(QMessageBox::StandardButton button)

This is an overloaded function.

Adds a standard button to the message box if it is valid to do so, and returns the push button.

This function was introduced in Qt 4.2.

See also setStandardButtons().

QAbstractButton *QMessageBox::button(QMessageBox::StandardButton which) const

Returns a pointer corresponding to the standard button which, or nullptr if the standard button doesn't exist in this message box.

This function was introduced in Qt 4.2.

See also standardButtons and standardButton().

QMessageBox::ButtonRole QMessageBox::buttonRole(QAbstractButton *button) const

Returns the button role for the specified button. This function returns InvalidRole if button is nullptr or has not been added to the message box.

This function was introduced in Qt 4.5.

See also buttons() and addButton().

QList<QAbstractButton *> QMessageBox::buttons() const

Returns a list of all the buttons that have been added to the message box.

This function was introduced in Qt 4.5.

See also buttonRole(), addButton(), and removeButton().

[override virtual protected] void QMessageBox::changeEvent(QEvent *ev)

Reimplements: QWidget::changeEvent(QEvent *event).

QCheckBox *QMessageBox::checkBox() const

Returns the checkbox shown on the dialog. This is nullptr if no checkbox is set.

This function was introduced in Qt 5.2.

See also setCheckBox().

QAbstractButton *QMessageBox::clickedButton() const

Returns the button that was clicked by the user, or nullptr if the user hit the Esc key and no escape button was set.

If exec() hasn't been called yet, returns nullptr.

Example:

QMessageBox messageBox(this);
QAbstractButton *disconnectButton =
      messageBox.addButton(tr("Disconnect"), QMessageBox::ActionRole);
...
messageBox.exec();
if (messageBox.clickedButton() == disconnectButton) {
    ...
}

This function was introduced in Qt 4.2.

See also standardButton() and button().

[override virtual protected] void QMessageBox::closeEvent(QCloseEvent *e)

Reimplements: QDialog::closeEvent(QCloseEvent *e).

[static] QMessageBox::StandardButton QMessageBox::critical(QWidget *parent, const QString &title, const QString &text, QMessageBox::StandardButtons buttons = Ok, QMessageBox::StandardButton defaultButton = NoButton)

Opens a critical message box with the given title and text in front of the specified parent widget.

The standard buttons are added to the message box. defaultButton specifies the button used when Enter is pressed. defaultButton must refer to a button that was given in buttons. If defaultButton is QMessageBox::NoButton, QMessageBox chooses a suitable default automatically.

Returns the identity of the standard button that was clicked. If Esc was pressed instead, the escape button is returned.

The message box is an application modal dialog box.

Warning: Do not delete parent during the execution of the dialog. If you want to do this, you should create the dialog yourself using one of the QMessageBox constructors.

This function was introduced in Qt 4.2.

See also question(), warning(), and information().

QPushButton *QMessageBox::defaultButton() const

Returns the button that should be the message box's default button. Returns nullptr if no default button was set.

This function was introduced in Qt 4.2.

See also setDefaultButton(), addButton(), and QPushButton::setDefault().

QAbstractButton *QMessageBox::escapeButton() const

Returns the button that is activated when escape is pressed.

By default, QMessageBox attempts to automatically detect an escape button as follows:

1. If there is only one button, it is made the escape button.
2. If there is a Cancel button, it is made the escape button.
3. On macOS only, if there is exactly one button with the role QMessageBox::RejectRole, it is made the escape button.

When an escape button could not be automatically detected, pressing Esc has no effect.

This function was introduced in Qt 4.2.

See also setEscapeButton() and addButton().

[override virtual protected] bool QMessageBox::event(QEvent *e)

Reimplements: QWidget::event(QEvent *event).

[static] QMessageBox::StandardButton QMessageBox::information(QWidget *parent, const QString &title, const QString &text, QMessageBox::StandardButtons buttons = Ok, QMessageBox::StandardButton defaultButton = NoButton)

Opens an information message box with the given title and text in front of the specified parent widget.

The standard buttons are added to the message box. defaultButton specifies the button used when Enter is pressed. defaultButton must refer to a button that was given in buttons. If defaultButton is QMessageBox::NoButton, QMessageBox chooses a suitable default automatically.

Returns the identity of the standard button that was clicked. If Esc was pressed instead, the escape button is returned.

The message box is an application modal dialog box.

Warning: Do not delete parent during the execution of the dialog. If you want to do this, you should create the dialog yourself using one of the QMessageBox constructors.

This function was introduced in Qt 4.2.

See also question(), warning(), and critical().

[override virtual protected] void QMessageBox::keyPressEvent(QKeyEvent *e)

Reimplements: QDialog::keyPressEvent(QKeyEvent *e).

void QMessageBox::open(QObject *receiver, const char *member)

Opens the dialog and connects its finished() or buttonClicked() signal to the slot specified by receiver and member. If the slot in member has a pointer for its first parameter the connection is to buttonClicked(), otherwise the connection is to finished().

The signal will be disconnected from the slot when the dialog is closed.

[static] QMessageBox::StandardButton QMessageBox::question(QWidget *parent, const QString &title, const QString &text, QMessageBox::StandardButtons buttons = StandardButtons(Yes | No), QMessageBox::StandardButton defaultButton = NoButton)

Opens a question message box with the given title and text in front of the specified parent widget.

The standard buttons are added to the message box. defaultButton specifies the button used when Enter is pressed. defaultButton must refer to a button that was given in buttons. If defaultButton is QMessageBox::NoButton, QMessageBox chooses a suitable default automatically.

Returns the identity of the standard button that was clicked. If Esc was pressed instead, the escape button is returned.

The message box is an application modal dialog box.

Warning: Do not delete parent during the execution of the dialog. If you want to do this, you should create the dialog yourself using one of the QMessageBox constructors.

This function was introduced in Qt 4.2.

See also information(), warning(), and critical().

void QMessageBox::removeButton(QAbstractButton *button)

Removes button from the button box without deleting it.

This function was introduced in Qt 4.2.

See also addButton() and setStandardButtons().

[override virtual protected] void QMessageBox::resizeEvent(QResizeEvent *event)

Reimplements: QDialog::resizeEvent(QResizeEvent *).

void QMessageBox::setCheckBox(QCheckBox *cb)

Sets the checkbox cb on the message dialog. The message box takes ownership of the checkbox. The argument cb can be nullptr to remove an existing checkbox from the message box.

This function was introduced in Qt 5.2.

See also checkBox().

void QMessageBox::setDefaultButton(QPushButton *button)

Sets the message box's default button to button.

This function was introduced in Qt 4.2.

See also defaultButton(), addButton(), and QPushButton::setDefault().

void QMessageBox::setDefaultButton(QMessageBox::StandardButton button)

Sets the message box's default button to button.

This function was introduced in Qt 4.3.

See also addButton() and QPushButton::setDefault().

void QMessageBox::setEscapeButton(QAbstractButton *button)

Sets the button that gets activated when the Escape key is pressed to button.

This function was introduced in Qt 4.2.

See also escapeButton(), addButton(), and clickedButton().

void QMessageBox::setEscapeButton(QMessageBox::StandardButton button)

Sets the buttons that gets activated when the Escape key is pressed to button.

This function was introduced in Qt 4.3.

See also addButton() and clickedButton().

void QMessageBox::setWindowModality(Qt::WindowModality windowModality)

This function shadows QWidget::setWindowModality().

Sets the modality of the message box to windowModality.

On macOS, if the modality is set to Qt::WindowModal and the message box has a parent, then the message box will be a Qt::Sheet, otherwise the message box will be a standard dialog.

This function was introduced in Qt 4.2.

void QMessageBox::setWindowTitle(const QString &title)

This function shadows QWidget::setWindowTitle().

Sets the title of the message box to title. On macOS, the window title is ignored (as required by the macOS Guidelines).

This function was introduced in Qt 4.2.

[override virtual protected] void QMessageBox::showEvent(QShowEvent *e)

Reimplements: QDialog::showEvent(QShowEvent *event).

QMessageBox::StandardButton QMessageBox::standardButton(QAbstractButton *button) const

Returns the standard button enum value corresponding to the given button, or NoButton if the given button isn't a standard button.

This function was introduced in Qt 4.2.

See also button() and standardButtons().

[static] QMessageBox::StandardButton QMessageBox::warning(QWidget *parent, const QString &title, const QString &text, QMessageBox::StandardButtons buttons = Ok, QMessageBox::StandardButton defaultButton = NoButton)

Opens a warning message box with the given title and text in front of the specified parent widget.

The standard buttons are added to the message box. defaultButton specifies the button used when Enter is pressed. defaultButton must refer to a button that was given in buttons. If defaultButton is QMessageBox::NoButton, QMessageBox chooses a suitable default automatically.

Returns the identity of the standard button that was clicked. If Esc was pressed instead, the escape button is returned.

The message box is an application modal dialog box.

Warning: Do not delete parent during the execution of the dialog. If you want to do this, you should create the dialog yourself using one of the QMessageBox constructors.

This function was introduced in Qt 4.2.

See also question(), information(), and critical().