QSignalMapper ¶

概要 ¶

详细描述 ¶

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 the map() slot which will emit a signal (it could be mappedInt() , mappedString() , mappedWidget() and mappedObject() ) with a value associated with the original signalling object. Mappings can be removed later using removeMappings() .

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’s clicked() signal to the signal mapper’s map() slot, and create a mapping in the signal mapper from each button to the button’s text. Finally we connect the signal mapper’s mappedString() signal to the custom widget’s clicked() signal. When the user clicks a button, the custom widget will emit a single clicked() 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);
}
											

另请参阅

QObject QButtonGroup QActionGroup

class QSignalMapper ( [ parent=None ] ) ¶

param parent

QObject

构造 QSignalMapper 采用父级 parent .

PySide2.QtCore.QSignalMapper. map ( ) ¶

This slot emits signals based on which object sends signals to it.

PySide2.QtCore.QSignalMapper. map ( sender ) ¶

参数

sender – QObject

This slot emits signals based on the sender 对象。

PySide2.QtCore.QSignalMapper. mapped ( arg__1 ) ¶

参数

arg__1 – int

注意

此函数被弃用。

PySide2.QtCore.QSignalMapper. mapped ( arg__1 ) ¶

参数

arg__1 – QWidget

注意

此函数被弃用。

PySide2.QtCore.QSignalMapper. mapped ( arg__1 ) ¶

参数

arg__1 – QObject

注意

此函数被弃用。

PySide2.QtCore.QSignalMapper. mapped ( arg__1 ) ¶

参数

arg__1 – unicode

注意

此函数被弃用。

PySide2.QtCore.QSignalMapper. mappedInt ( arg__1 ) ¶

参数

arg__1 – int

PySide2.QtCore.QSignalMapper. mappedObject ( arg__1 ) ¶

参数

arg__1 – QObject

PySide2.QtCore.QSignalMapper. mappedString ( arg__1 ) ¶

参数

arg__1 – unicode

PySide2.QtCore.QSignalMapper. mappedWidget ( arg__1 ) ¶

参数

arg__1 – QWidget

PySide2.QtCore.QSignalMapper. 映射 ( object ) ¶

参数

object – QObject

返回类型

QObject

此函数重载 mapping() .

Returns the sender QObject that is associated with the object .

PySide2.QtCore.QSignalMapper. 映射 ( widget ) ¶

参数

widget – QWidget

返回类型

QObject

此函数重载 mapping() .

Returns the sender QObject that is associated with the widget .

PySide2.QtCore.QSignalMapper. 映射 ( text ) ¶

参数

text – unicode

返回类型

QObject

PySide2.QtCore.QSignalMapper. 映射 ( id ) ¶

参数

id – int

返回类型

QObject

Returns the sender QObject that is associated with the id .

另请参阅

setMapping()

PySide2.QtCore.QSignalMapper. removeMappings ( sender ) ¶

参数

sender – QObject

Removes all mappings for sender .

This is done automatically when mapped objects are destroyed.

注意

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 ) ¶

参数

• sender – QObject

• object – QObject

Adds a mapping so that when map() is signalled from the sender ，信号 mappedObject ( object ) is emitted.

There may be at most one object for each sender.

PySide2.QtCore.QSignalMapper. setMapping ( sender , widget ) ¶

参数

• sender – QObject

• widget – QWidget

Adds a mapping so that when map() is signalled from the sender ，信号 mappedWidget ( widget ) is emitted.

There may be at most one widget for each sender.

PySide2.QtCore.QSignalMapper. setMapping ( sender , text ) ¶

参数

• sender – QObject

• text – unicode

PySide2.QtCore.QSignalMapper. setMapping ( sender , id ) ¶

参数

• sender – QObject

• id – int

Adds a mapping so that when map() is signalled from the given sender ，信号 mappedInt ( id ) is emitted.

There may be at most one integer ID for each sender.

另请参阅

mapping()