QSignalMapper¶
The
QSignalMapper
class bundles signals from identifiable senders. More…
Synopsis¶
Functions¶
def
mapping
(id)def
mapping
(object)def
mapping
(text)def
mapping
(widget)def
removeMappings
(sender)def
setMapping
(sender, id)def
setMapping
(sender, object)def
setMapping
(sender, text)def
setMapping
(sender, widget)
Slots¶
Signals¶
def
mapped
(arg__1)def
mapped
(arg__1)def
mapped
(arg__1)def
mapped
(arg__1)def
mappedInt
(arg__1)def
mappedObject
(arg__1)def
mappedString
(arg__1)def
mappedWidget
(arg__1)
Detailed Description¶
This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters corresponding to the object that sent the signal. Note that in most cases you can use lambdas for passing custom parameters to slots. This is less costly and will simplify the code.
The class supports the mapping of particular strings, integers, objects and widgets with particular objects using
setMapping()
. The objects’ signals can then be connected to themap()
slot which will emit a signal (it could bemappedInt()
,mappedString()
,mappedWidget()
andmappedObject()
) with a value associated with the original signalling object. Mappings can be removed later usingremoveMappings()
.Example: Suppose we want to create a custom widget that contains a group of buttons (like a tool palette). One approach is to connect each button’s
clicked()
signal to its own custom slot; but in this example we want to connect all the buttons to a single slot and parameterize the slot by the button that was clicked.Here’s the definition of a simple custom widget that has a single signal,
clicked()
, which is emitted with the text of the button that was clicked:class ButtonWidget(QWidget): def __init__(self, texts, parent=None): QWidget.__init__(self, parent) ...The only function that we need to implement is the constructor:
ButtonWidget::ButtonWidget(const QStringList &texts, QWidget *parent) : QWidget(parent) { signalMapper = new QSignalMapper(this); QGridLayout *gridLayout = new QGridLayout; for (int i = 0; i < texts.size(); ++i) { QPushButton *button = new QPushButton(texts[i]); connect(button, &QPushButton::clicked, signalMapper, &QSignalMapper::map); signalMapper->setMapping(button, texts[i]); gridLayout->addWidget(button, i / 3, i % 3); } connect(signalMapper, &QSignalMapper::mappedString, this, &ButtonWidget::clicked); setLayout(gridLayout); }A list of texts is passed to the constructor. A signal mapper is constructed and for each text in the list a
QPushButton
is created. We connect each button’sclicked()
signal to the signal mapper’smap()
slot, and create a mapping in the signal mapper from each button to the button’s text. Finally we connect the signal mapper’smappedString()
signal to the custom widget’sclicked()
signal. When the user clicks a button, the custom widget will emit a singleclicked()
signal whose argument is the text of the button the user clicked.This class was mostly useful before lambda functions could be used as slots. The example above can be rewritten simpler without
QSignalMapper
by connecting to a lambda function.ButtonWidget::ButtonWidget(const QStringList &texts, QWidget *parent) : QWidget(parent) { QGridLayout *gridLayout = new QGridLayout; for (int i = 0; i < texts.size(); ++i) { QString text = texts[i]; QPushButton *button = new QPushButton(text); connect(button, &QPushButton::clicked, [this, text] { clicked(text); }); gridLayout->addWidget(button, i / 3, i % 3); } setLayout(gridLayout); }See also
QObject
QButtonGroup
QActionGroup
- class PySide2.QtCore.QSignalMapper([parent=None])¶
- param parent:
Constructs a
QSignalMapper
with parentparent
.
- PySide2.QtCore.QSignalMapper.map()¶
This slot emits signals based on which object sends signals to it.
- PySide2.QtCore.QSignalMapper.map(sender)
- Parameters:
sender –
PySide2.QtCore.QObject
This slot emits signals based on the
sender
object.
- PySide2.QtCore.QSignalMapper.mapped(arg__1)¶
- Parameters:
arg__1 – int
Note
This function is deprecated.
- PySide2.QtCore.QSignalMapper.mapped(arg__1)
- Parameters:
arg__1 –
PySide2.QtWidgets.QWidget
Note
This function is deprecated.
- PySide2.QtCore.QSignalMapper.mapped(arg__1)
- Parameters:
arg__1 –
PySide2.QtCore.QObject
Note
This function is deprecated.
- PySide2.QtCore.QSignalMapper.mapped(arg__1)
- Parameters:
arg__1 – str
Note
This function is deprecated.
- PySide2.QtCore.QSignalMapper.mappedInt(arg__1)¶
- Parameters:
arg__1 – int
- PySide2.QtCore.QSignalMapper.mappedObject(arg__1)¶
- Parameters:
arg__1 –
PySide2.QtCore.QObject
- PySide2.QtCore.QSignalMapper.mappedString(arg__1)¶
- Parameters:
arg__1 – str
- PySide2.QtCore.QSignalMapper.mappedWidget(arg__1)¶
- Parameters:
arg__1 –
PySide2.QtWidgets.QWidget
- PySide2.QtCore.QSignalMapper.mapping(object)¶
- Parameters:
object –
PySide2.QtCore.QObject
- Return type:
This function overloads
mapping()
.Returns the sender
QObject
that is associated with theobject
.
- PySide2.QtCore.QSignalMapper.mapping(widget)
- Parameters:
widget –
PySide2.QtWidgets.QWidget
- Return type:
This function overloads
mapping()
.Returns the sender
QObject
that is associated with thewidget
.
- PySide2.QtCore.QSignalMapper.mapping(text)
- Parameters:
text – str
- Return type:
- PySide2.QtCore.QSignalMapper.mapping(id)
- Parameters:
id – int
- Return type:
Returns the sender
QObject
that is associated with theid
.See also
- PySide2.QtCore.QSignalMapper.removeMappings(sender)¶
- Parameters:
sender –
PySide2.QtCore.QObject
Removes all mappings for
sender
.This is done automatically when mapped objects are destroyed.
Note
This does not disconnect any signals. If
sender
is not destroyed then this will need to be done explicitly if required.
- PySide2.QtCore.QSignalMapper.setMapping(sender, object)¶
- Parameters:
sender –
PySide2.QtCore.QObject
object –
PySide2.QtCore.QObject
Adds a mapping so that when
map()
is signalled from thesender
, the signalmappedObject
(object
) is emitted.There may be at most one object for each sender.
- PySide2.QtCore.QSignalMapper.setMapping(sender, widget)
- Parameters:
sender –
PySide2.QtCore.QObject
widget –
PySide2.QtWidgets.QWidget
Adds a mapping so that when
map()
is signalled from thesender
, the signalmappedWidget
(widget
) is emitted.There may be at most one widget for each sender.
- PySide2.QtCore.QSignalMapper.setMapping(sender, text)
- Parameters:
sender –
PySide2.QtCore.QObject
text – str
- PySide2.QtCore.QSignalMapper.setMapping(sender, id)
- Parameters:
sender –
PySide2.QtCore.QObject
id – int
Adds a mapping so that when
map()
is signalled from the givensender
, the signalmappedInt
(id
) is emitted.There may be at most one integer ID for each sender.
See also
© 2022 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.