[英]Can't pass QMap through to SLOT
So, this works: 所以,这有效:
.h 。H
public slots:
void addMenu(QString passedName);
signals:
void clicked(const QString &text);
.cpp 的.cpp
signalMapper = new QSignalMapper(this);
signalMapper->setMapping(button, QString("passed_value"));
connect(button, SIGNAL(clicked()), signalMapper, SLOT(map()));
connect(signalMapper, SIGNAL(mapped(QString)), this, SLOT(addMenu(QString)));
Now, I am trying to pass a QMap < QString, QString > through to addMenu instead of just a QString, but I get the error: no matching function for call to 'QSignalMapper::setMapping'. 现在,我试图将QMap <QString,QString>传递给addMenu而不是QString,但是我得到了错误:没有匹配的函数来调用'QSignalMapper :: setMapping'。 Do I need to create a typeDef or something? 我是否需要创建typeDef或其他内容?
.h 。H
public slots:
void addMenu(QMap < QString, QString > map);
signals:
void clicked(const QMap < QString, QString > &map);
.cpp 的.cpp
//map is defined above
signalMapper = new QSignalMapper(this);
signalMapper->setMapping(button, map);
connect(button, SIGNAL(clicked()), signalMapper, SLOT(map()));
connect(signalMapper, SIGNAL(mapped(QObject*)), this, SLOT(addMenu(QMap < QString, QString >)));
EDIT: I also tried adding a typeDef, but still getting same error. 编辑:我也尝试添加typeDef,但仍然出现相同的错误。
.h 。H
public:
typedef QMap < QString, QString > passedMapType;
public slots:
void addMenu(passedMapType map);
signals:
void clicked(passedMapType map);
.cpp 的.cpp
passedMapType passedMap;
passedMap.insert(QString("key"), QString("value"));
signalMapper = new QSignalMapper(this);
signalMapper->setMapping(button, passedMap);
connect(button, SIGNAL(clicked()), signalMapper, SLOT(map()));
connect(signalMapper, SIGNAL(mapped(QObject*)), this, SLOT(addMenu(passedMapType));
....
addMenu(passedMapType passedMap) {
}
Use typedefs. 使用typedef。 My feeling is that the comma between the two QString template parameters is a problem in macro expansion. 我的感觉是两个QString模板参数之间的逗号是宏扩展中的问题。
"Now, I am trying to pass a QMap < QString, QString > through to addMenu instead of just a QString, but I get the error: no matching function for call to 'QSignalMapper::setMapping'." “现在,我试图将QMap <QString,QString>传递给addMenu而不是QString,但是我得到了错误:没有匹配的函数来调用'QSignalMapper :: setMapping'。”
That's not a general signal/slot or macro expansion problem, but a limitation of QSignalMapper. 这不是一般的信号/插槽或宏扩展问题,而是QSignalMapper的局限性。 You can't pass a QMap to setMapping, only int, QString, QWidget* and QObject*. 您不能将QMap传递给setMapping,只能传递int,QString,QWidget *和QObject *。 See the QSignalMapper documentation . 请参阅QSignalMapper文档 。
connect(signalMapper, SIGNAL(mapped(QObject*)), this, SLOT(addMenu(passedMapType));
That wouldn't work either, because the signatures are incompatible: QObject* vs. QMap. 那也不行,因为签名是不兼容的:QObject * vs. QMap。
What I would do: Hold a QMap<QObject*,PassedMapType> in the owner of the buttons, create a slot slotClicked(QObject*) there, connected to the clicked() signals of the buttons, and then look up the PassedMapType object from the map, using the passed QObject*. 我要做什么:在按钮的所有者中持有QMap <QObject *,PassedMapType>,在其中创建一个插槽slotClicked(QObject *),连接到按钮的clicked()信号,然后从中查找PassedMapType对象。使用传递的QObject *映射。 Edit: added some pseudo code to illustrate it: 编辑:添加了一些伪代码来说明它:
QMap<QWidget*, QMap<QString, QString> > map; //member of the class
//when creating the buttons:
for each button b:
signalMapper->setMapping( b, b );
map.insert( b, someMapForThisButton );
connect( signalMapper, SIGNAL(mapped(QWidget*)), this, SLOT(addMenuForButton(QWidget*)) );
//the slot:
void addMenuForButton(QWidget* w) {
const QMap<QString, QString> m = map.value( w );
create menu...
}
As a nice work around you can use QObject. 作为一项不错的工作,您可以使用QObject。 QObject has an embedded QMap inside. QObject内部具有嵌入式QMap。 Here is how it goes: 这是怎么回事:
void sender() {
...
...
QObject *data = new QObject(0);
data->setProperty("Name","xxxx");
data->setProperty("Address","yyyy");
//You can also send QImage
QImage image;
...
data->setProperty("Image",image);
emit dataReady(data);
}
signals:
void dataReady(QObject*);
public slots:
void receiver(QObject *data) {
QString Name = data->property("Name").toString();
QString Address = data->property("Address").toString();
QImage image = data->property("Image").value<QImage>();
data->deleteLater();
}
This is a pure guess, but you may need to use pointer types instead? 这纯粹是猜测,但您可能需要改用指针类型? I never had very much luck passing by reference with &. 我从来没有碰过&运气。
public slots:
void addMenu(QMap<QString, QString> *map);
signals:
void clicked(QMap<QString, QString> *map);
The signal and slot must have the same argument types (it's a function call, of sorts), so this line is wrong: 信号和插槽必须具有相同的参数类型(这是一个函数调用,类似),因此此行是错误的:
connect(signalMapper, SIGNAL(mapped(QObject*)), this, SLOT(addMenu(passedMapType));
You might need to rethink your logic a bit to make that work. 您可能需要重新考虑一下自己的逻辑才能使其正常工作。
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