内容

• 公共函数
• 公共槽
• 信号
• 静态公共成员
• 详细描述

QSignalMapper 类

The QSignalMapper class bundles signals from identifiable senders. 更多...

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

• 所有成员列表，包括继承成员
• 过时成员

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 )

• 32 公共函数继承自 QObject

公共槽

void	map ()
void	map (QObject * sender )

• 1 公共槽继承自 QObject

信号

void	mapped (int i )
void	mapped (const QString & text )
void	mapped (QWidget * widget )
void	mapped (QObject * object )

• 2 信号继承自 QObject

静态公共成员

const QMetaObject

staticMetaObject

• 10 静态公共成员继承自 QObject

额外继承成员

• 1 特性继承自 QObject
• 9 保护函数继承自 QObject

详细描述

The QSignalMapper class bundles signals from identifiable senders.

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 or integers with particular objects using setMapping (). The objects' signals can then be connected to the map () slot which will emit the mapped () signal with the string or integer 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 = 0);
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, SIGNAL(clicked()), signalMapper, SLOT(map()));
        signalMapper->setMapping(button, texts[i]);
        gridLayout->addWidget(button, i / 3, i % 3);
    }
    connect(signalMapper, SIGNAL(mapped(QString)),
            this, SIGNAL(clicked(QString)));
    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 mapped () 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, [=] { 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 .

[虚拟] QSignalMapper:: ~QSignalMapper ()

销毁 QSignalMapper .

[slot] void QSignalMapper:: map ()

此槽基于哪个对象向它发送信号来发射信号。

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

此槽发射信号基于 sender 对象。

[signal] void QSignalMapper:: mapped ( 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 .

注意： 信号 mapped 在此类中被重载。通过使用函数指针句法连接到此信号，Qt 提供用于获得如此范例展示的函数指针的方便帮助程序：

connect(signalMapper, QOverload<int>::of(&QSignalMapper::mapped),
    [=](int i){ /* ... */ });
					

另请参阅 setMapping ().

[signal] void QSignalMapper:: mapped (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 .

注意： 信号 mapped 在此类中被重载。通过使用函数指针句法连接到此信号，Qt 提供用于获得如此范例展示的函数指针的方便帮助程序：

connect(signalMapper, QOverload<const QString &>::of(&QSignalMapper::mapped),
    [=](const QString &text){ /* ... */ });
					

另请参阅 setMapping ().

[signal] void QSignalMapper:: mapped ( 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 .

注意： 信号 mapped 在此类中被重载。通过使用函数指针句法连接到此信号，Qt 提供用于获得如此范例展示的函数指针的方便帮助程序：

connect(signalMapper, QOverload<QWidget *>::of(&QSignalMapper::mapped),
    [=](QWidget *widget){ /* ... */ });
					

另请参阅 setMapping ().

[signal] void QSignalMapper:: mapped ( 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 .

注意： 信号 mapped 在此类中被重载。通过使用函数指针句法连接到此信号，Qt 提供用于获得如此范例展示的函数指针的方便帮助程序：

connect(signalMapper, QOverload<QObject *>::of(&QSignalMapper::mapped),
    [=](QObject *object){ /* ... */ });
					

另请参阅 setMapping ().

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

此函数重载 映射 ().

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

此函数重载 映射 ().

Returns the sender QObject that is associated with the widget .

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

此函数重载 映射 ().

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 , the signal mapped( 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 , the signal mapped( 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 , the signal mapped( 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 , the signal mapped( object ) is emitted.

There may be at most one object for each sender.