QSignalMapper 类

QSignalMapper 类捆绑来自可识别发送器的信号。 更多...

头：	#include <QSignalMapper>
qmake:	QT += core
继承：	QObject

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公共函数

	QSignalMapper (QObject * parent = nullptr)
virtual	~QSignalMapper ()
QObject *	映射 (int id ) const
QObject *	映射 (const QString & id ) const
QObject *	映射 (QWidget * widget ) const
QObject *	映射 (QObject * object ) const
void	removeMappings (QObject * sender )
void	setMapping (QObject * sender , int id )
void	setMapping (QObject * sender , const QString & text )
void	setMapping (QObject * sender , QWidget * widget )
void	setMapping (QObject * sender , QObject * object )

公共槽

void	map (QObject * sender )
void	map ()

信号

void	mappedInt (int i )
void	mappedObject (QObject * object )
void	mappedString (const QString & text )
void	mappedWidget (QWidget * widget )

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 () 和 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 : public QWidget
{
    Q_OBJECT
public:
    ButtonWidget(const QStringList &texts, QWidget *parent = nullptr);
signals:
    void clicked(const QString &text);
private:
    QSignalMapper *signalMapper;
};
					

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 ，和 QActionGroup .

成员函数文档编制

QSignalMapper:: QSignalMapper ( QObject * parent = nullptr)

构造 QSignalMapper 采用父级 parent .

[slot] void QSignalMapper:: map ( QObject * sender )

此槽发射信号基于 sender 对象。

[slot] void QSignalMapper:: map ()

此槽基于哪个对象向它发送信号来发射信号。

[signal] void QSignalMapper:: mappedInt ( int i )

此信号发射当 map () is signalled from an object that has an integer mapping set. The object's mapped integer is passed in i .

该函数在 Qt 5.15 引入。

另请参阅 setMapping ().

[signal] void QSignalMapper:: mappedObject ( QObject * object )

此信号发射当 map () is signalled from an object that has an object mapping set. The object provided by the map is passed in object .

该函数在 Qt 5.15 引入。

另请参阅 setMapping ().

[signal] void QSignalMapper:: mappedString (const QString & text )

此信号发射当 map () is signalled from an object that has a string mapping set. The object's mapped string is passed in text .

该函数在 Qt 5.15 引入。

另请参阅 setMapping ().

[signal] void QSignalMapper:: mappedWidget ( QWidget * widget )

此信号发射当 map () is signalled from an object that has a widget mapping set. The object's mapped widget is passed in widget .

该函数在 Qt 5.15 引入。

另请参阅 setMapping ().

[虚拟] QSignalMapper:: ~QSignalMapper ()

销毁 QSignalMapper .

QObject *QSignalMapper:: 映射 ( int id ) const

Returns the sender QObject that is associated with the id .

另请参阅 setMapping ().

QObject *QSignalMapper:: 映射 (const QString & id ) const

This function overloads mapping().

QObject *QSignalMapper:: 映射 ( QWidget * widget ) const

This function overloads mapping().

Returns the sender QObject that is associated with the widget .

QObject *QSignalMapper:: 映射 ( QObject * object ) const

This function overloads mapping().

Returns the sender QObject that is associated with the object .

void QSignalMapper:: removeMappings ( QObject * sender )

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.

void QSignalMapper:: setMapping ( QObject * sender , int id )

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 映射 ().

void QSignalMapper:: setMapping ( QObject * sender , const QString & text )

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

There may be at most one text for each sender.

void QSignalMapper:: setMapping ( QObject * sender , QWidget * widget )

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.

void QSignalMapper:: setMapping ( QObject * sender , QObject * object )

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.

内容

• 公共函数

• 公共槽

• 信号

• 详细描述