QMessageBox¶

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

Synopsis¶

Functions¶

def addButton (button)
def addButton (button, role)
def addButton (text, role)
def button (which)
def buttonRole (button)
def buttonText (button)
def buttons ()
def checkBox ()
def clickedButton ()
def defaultButton ()
def detailedText ()
def escapeButton ()
def icon ()
def iconPixmap ()
def informativeText ()
def open (receiver, member)
def removeButton (button)
def setButtonText (button, text)
def setCheckBox (cb)
def setDefaultButton (button)
def setDefaultButton (button)
def setDetailedText (text)
def setEscapeButton (button)
def setEscapeButton (button)
def setIcon (arg__1)
def setIconPixmap (pixmap)
def setInformativeText (text)
def setStandardButtons (buttons)
def setText (text)
def setTextFormat (format)
def setTextInteractionFlags (flags)
def standardButton (button)
def standardButtons ()
def text ()
def textFormat ()
def textInteractionFlags ()

Signals¶

def buttonClicked (button)

Static functions¶

def about (parent, title, text)
def aboutQt (parent[, title=”“])
def critical (parent, title, text, button0, button1)
def critical (parent, title, text[, buttons=QMessageBox.Ok[, defaultButton=NoButton]])
def information (parent, title, text, button0[, button1=NoButton])
def information (parent, title, text[, buttons=QMessageBox.Ok[, defaultButton=NoButton]])
def question (parent, title, text, button0, button1)
def question (parent, title, text[, buttons=QMessageBox.StandardButtons(Yes | No)[, defaultButton=NoButton]])
def standardIcon (icon)
def warning (parent, title, text, button0, button1)
def warning (parent, title, text[, buttons=QMessageBox.Ok[, defaultButton=NoButton]])

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.
msgBox = QMessageBox()
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 .
msgBox = QMessageBox()
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)
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.
if ret == QMessageBox.Save:
    # Save was clicked
elif ret == QMessageBox.Discard:
    # Don't save was clicked
elif ret == QMessageBox.Cancel:
    # cancel was clicked
else:
    # should never be reached
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 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.
ret = QMessageBox.warning(self, self.tr("My Application"),
                               self.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,
msgBox = QMessageBox()
connectButton = msgBox.addButton(self.tr("Connect"), QMessageBox.ActionRole)
abortButton = msgBox.addButton(QMessageBox.Abort)

msgBox.exec_()

if msgBox.clickedButton() == connectButton:
    # connect
elif 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:

If there is only one button, it is the button activated when Esc is pressed.

If there is a Cancel button, it is the button activated when Esc is pressed.

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 Application Example

class QMessageBox(icon, title, text[, buttons=QMessageBox.NoButton[, parent=None[, flags=Qt.Dialog | Qt.MSWindowsFixedSizeDialogHint]]])¶

QMessageBox([parent=None])

param parent

QWidget

param title

unicode

param buttons

StandardButtons

param flags

WindowFlags

param icon

Icon

param text

unicode

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 0 and you want your message box to appear as a Sheet of that parent, set the message box’s window modality to WindowModal (default). Otherwise, the message box will be a standard dialog.

See also

setWindowTitle() setText() setIcon() setStandardButtons()

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 Sheet of its parent , set the message box’s window modality to WindowModal or use open() . Otherwise, the message box will be a standard dialog.

PySide2.QtWidgets.QMessageBox.Icon¶

This enum has the following values:

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

PySide2.QtWidgets.QMessageBox.ButtonRole¶

PySide2.QtWidgets.QMessageBox.StandardButton¶

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

Constant	Description
QMessageBox.Ok	An “OK” button defined with the `AcceptRole` .
QMessageBox.Open	An “Open” button defined with the `AcceptRole` .
QMessageBox.Save	A “Save” button defined with the `AcceptRole` .
QMessageBox.Cancel	A “Cancel” button defined with the `RejectRole` .
QMessageBox.Close	A “Close” button defined with the `RejectRole` .
QMessageBox.Discard	A “Discard” or “Don’t Save” button, depending on the platform, defined with the `DestructiveRole` .
QMessageBox.Apply	An “Apply” button defined with the `ApplyRole` .
QMessageBox.Reset	A “Reset” button defined with the `ResetRole` .
QMessageBox.RestoreDefaults	A “Restore Defaults” button defined with the `ResetRole` .
QMessageBox.Help	A “Help” button defined with the `HelpRole` .
QMessageBox.SaveAll	A “Save All” button defined with the `AcceptRole` .
QMessageBox.Yes	A “Yes” button defined with the `YesRole` .
QMessageBox.YesToAll	A “Yes to All” button defined with the `YesRole` .
QMessageBox.No	A “No” button defined with the `NoRole` .
QMessageBox.NoToAll	A “No to All” button defined with the `NoRole` .
QMessageBox.Abort	An “Abort” button defined with the `RejectRole` .
QMessageBox.Retry	A “Retry” button defined with the `AcceptRole` .
QMessageBox.Ignore	An “Ignore” button defined with the `AcceptRole` .
QMessageBox.NoButton	An invalid button.

The following values are obsolete:

Constant	Description
QMessageBox.YesAll	Use instead.
QMessageBox.NoAll	Use instead.
QMessageBox.Default	Use the `defaultButton` argument of `information()` , `warning()` , etc. instead, or call `setDefaultButton()` .
QMessageBox.Escape	Call `setEscapeButton()` instead.
QMessageBox.FlagMask
QMessageBox.ButtonMask

See also

ButtonRole standardButtons

static PySide2.QtWidgets.QMessageBox.about(parent, title, text)¶

Parameters

parent – QWidget
title – unicode
text – unicode

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

looks for a suitable icon in four locations:

It prefers parent->icon() if that exists.
If not, it tries the top-level widget containing parent.
If that fails, it tries the PySide2.QtWidgets.QApplication.activeWindow()
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

windowIcon() activeWindow()

static PySide2.QtWidgets.QMessageBox.aboutQt(parent[, title=""])¶

Parameters

parent – QWidget
title – unicode

Displays a simple message box about Qt, with the given title and centered over parent (if parent is not 0). 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

aboutQt()

PySide2.QtWidgets.QMessageBox.addButton(button, role)¶

Parameters

button – QAbstractButton
role – ButtonRole

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

PySide2.QtWidgets.QMessageBox.addButton(button)

Parameters: button – StandardButton
Return type: QPushButton

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.

See also

setStandardButtons()

PySide2.QtWidgets.QMessageBox.addButton(text, role)

Parameters

text – unicode
role – ButtonRole

Return type

QPushButton

PySide2.QtWidgets.QMessageBox.button(which)¶

Parameters: which – StandardButton
Return type: QAbstractButton

Returns a pointer corresponding to the standard button which , or 0 if the standard button doesn’t exist in this message box.

See also

standardButtons standardButton()

PySide2.QtWidgets.QMessageBox.buttonClicked(button)¶

Parameters: button – QAbstractButton

PySide2.QtWidgets.QMessageBox.buttonRole(button)¶

Parameters: button – QAbstractButton
Return type: ButtonRole

Returns the button role for the specified button . This function returns InvalidRole if button is 0 or has not been added to the message box.

See also

buttons() addButton()

PySide2.QtWidgets.QMessageBox.buttonText(button)¶

Parameters: button – int
Return type: unicode

Returns the text of the message box button button , or an empty string if the message box does not contain the button.

Use button() and text() instead.

See also

setButtonText()

PySide2.QtWidgets.QMessageBox.buttons()¶

Return type

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

PySide2.QtWidgets.QMessageBox.checkBox()¶

Return type: QCheckBox

Returns the checkbox shown on the dialog. This is 0 if no checkbox is set.

See also

setCheckBox()

PySide2.QtWidgets.QMessageBox.clickedButton()¶

Return type: QAbstractButton

Returns the button that was clicked by the user, or 0 if the user hit the Esc key and no escape button was set.

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

Example:

messageBox = QMessageBox(self)
disconnectButton = messageBox.addButton(self.tr("Disconnect"),
                                        QMessageBox.ActionRole)
...
messageBox.exec_()
if messageBox.clickedButton() == disconnectButton:
    ...

See also

standardButton() button()

static PySide2.QtWidgets.QMessageBox.critical(parent, title, text, button0, button1)¶

Parameters

parent – QWidget
title – unicode
text – unicode
button0 – StandardButton
button1 – StandardButton

Return type

int

static PySide2.QtWidgets.QMessageBox.critical(parent, title, text[, buttons=QMessageBox.Ok[, defaultButton=NoButton]])

Parameters

parent – QWidget
title – unicode
text – unicode
buttons – StandardButtons
defaultButton – StandardButton

Return type

StandardButton

PySide2.QtWidgets.QMessageBox.defaultButton()¶

Return type: QPushButton

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

PySide2.QtWidgets.QMessageBox.detailedText()¶

Return type: unicode

See also

setDetailedText()

PySide2.QtWidgets.QMessageBox.escapeButton()¶

Return type: QAbstractButton

Returns the button that is activated when escape is pressed.

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

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

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

See also

setEscapeButton() addButton()

PySide2.QtWidgets.QMessageBox.icon()¶

Return type: Icon

See also

setIcon()

PySide2.QtWidgets.QMessageBox.iconPixmap()¶

Return type: QPixmap

See also

setIconPixmap()

static PySide2.QtWidgets.QMessageBox.information(parent, title, text[, buttons=QMessageBox.Ok[, defaultButton=NoButton]])¶

Parameters

parent – QWidget
title – unicode
text – unicode
buttons – StandardButtons
defaultButton – StandardButton

Return type

StandardButton

static PySide2.QtWidgets.QMessageBox.information(parent, title, text, button0[, button1=NoButton])

Parameters

parent – QWidget
title – unicode
text – unicode
button0 – StandardButton
button1 – StandardButton

Return type

StandardButton

PySide2.QtWidgets.QMessageBox.informativeText()¶

Return type: unicode

See also

setInformativeText()

PySide2.QtWidgets.QMessageBox.open(receiver, member)¶

Parameters

receiver – QObject
member – str

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 PySide2.QtWidgets.QMessageBox.question(parent, title, text[, buttons=QMessageBox.StandardButtons(Yes | No)[, defaultButton=NoButton]])¶

Parameters

parent – QWidget
title – unicode
text – unicode
buttons – StandardButtons
defaultButton – StandardButton

Return type

StandardButton

static PySide2.QtWidgets.QMessageBox.question(parent, title, text, button0, button1)

Parameters

parent – QWidget
title – unicode
text – unicode
button0 – StandardButton
button1 – StandardButton

Return type

int

PySide2.QtWidgets.QMessageBox.removeButton(button)¶

Parameters: button – QAbstractButton

Removes button from the button box without deleting it.

See also

addButton() setStandardButtons()

PySide2.QtWidgets.QMessageBox.setButtonText(button, text)¶

Parameters

button – int
text – unicode

Sets the text of the message box button button to text . Setting the text of a button that is not in the message box is silently ignored.

Use addButton() instead.

See also

buttonText()

PySide2.QtWidgets.QMessageBox.setCheckBox(cb)¶

Parameters: cb – QCheckBox

Sets the checkbox cb on the message dialog. The message box takes ownership of the checkbox. The argument cb can be 0 to remove an existing checkbox from the message box.

See also

checkBox()

PySide2.QtWidgets.QMessageBox.setDefaultButton(button)¶

Parameters: button – StandardButton

Sets the message box’s default button to button .

See also

addButton() setDefault()

PySide2.QtWidgets.QMessageBox.setDefaultButton(button)

Parameters: button – QPushButton

Sets the message box’s default button to button .

PySide2.QtWidgets.QMessageBox.setDetailedText(text)¶

Parameters: text – unicode

See also

detailedText()

PySide2.QtWidgets.QMessageBox.setEscapeButton(button)¶

Parameters: button – QAbstractButton

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

PySide2.QtWidgets.QMessageBox.setEscapeButton(button)

Parameters: button – StandardButton

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

See also

addButton() clickedButton()

PySide2.QtWidgets.QMessageBox.setIcon(arg__1)¶

Parameters: arg__1 – Icon

See also

icon()

PySide2.QtWidgets.QMessageBox.setIconPixmap(pixmap)¶

Parameters: pixmap – QPixmap

See also

iconPixmap()

PySide2.QtWidgets.QMessageBox.setInformativeText(text)¶

Parameters: text – unicode

See also

informativeText()

PySide2.QtWidgets.QMessageBox.setStandardButtons(buttons)¶

Parameters: buttons – StandardButtons

See also

standardButtons()

PySide2.QtWidgets.QMessageBox.setText(text)¶

Parameters: text – unicode

See also

text()

PySide2.QtWidgets.QMessageBox.setTextFormat(format)¶

Parameters: format – TextFormat

See also

textFormat()

PySide2.QtWidgets.QMessageBox.setTextInteractionFlags(flags)¶

Parameters: flags – TextInteractionFlags

See also

textInteractionFlags()

PySide2.QtWidgets.QMessageBox.standardButton(button)¶

Parameters: button – QAbstractButton
Return type: StandardButton

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

See also

button() standardButtons()

PySide2.QtWidgets.QMessageBox.standardButtons()¶

Return type: StandardButtons

See also

setStandardButtons()

static PySide2.QtWidgets.QMessageBox.standardIcon(icon)¶

Parameters: icon – Icon
Return type: QPixmap

Returns the pixmap used for a standard icon. This allows the pixmaps to be used in more complex message boxes. icon specifies the required icon, e.g. Question , Information , Warning or Critical .

Call standardIcon() with SP_MessageBoxInformation etc. instead.

PySide2.QtWidgets.QMessageBox.text()¶

Return type: unicode

See also

setText()

PySide2.QtWidgets.QMessageBox.textFormat()¶

Return type: TextFormat

See also

setTextFormat()

PySide2.QtWidgets.QMessageBox.textInteractionFlags()¶

Return type: TextInteractionFlags

See also

setTextInteractionFlags()

static PySide2.QtWidgets.QMessageBox.warning(parent, title, text[, buttons=QMessageBox.Ok[, defaultButton=NoButton]])¶

Parameters

parent – QWidget
title – unicode
text – unicode
buttons – StandardButtons
defaultButton – StandardButton

Return type

StandardButton

static PySide2.QtWidgets.QMessageBox.warning(parent, title, text, button0, button1)

Parameters

parent – QWidget
title – unicode
text – unicode
button0 – StandardButton
button1 – StandardButton

Return type

int

Qt Documentation

Table of Contents

QMessageBox¶

Synopsis¶

Functions¶

Signals¶

Static functions¶

Detailed Description¶

The Property-based API¶

Rich Text and the Text Format Property¶

Severity Levels and the Icon and Pixmap Properties¶

The Static Functions API¶

Advanced Usage¶

Default and Escape Keys¶

	`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.