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[英]Is there possible pass Javascript Object from qml as QVariant to c++ layer as a parameter of slot?
[英]Passing QVariant from QML to C++
我正在嘗試將列表從QML發送到c ++。 我嘗試使用成功的字符串和整數,但是當我嘗試使用QVariant時出現錯誤:
QObject :: connect:../test_2206/main.cpp:31中沒有這樣的插槽MyClass :: cppSlot(QVariant)
我的main.qml
import QtQuick 2.4
import QtQuick.Layouts 1.1
import Material.ListItems 0.1 as ListItem
import Material.Extras 0.1
import QtQuick.Controls 1.3 as QuickControls
import QtQuick.Controls 1.4
import Material 0.2
Window {
visible: true
property var listCloud: ["nuage1", "nuage2", "nuage3", "nuage4"]
id: item
width: 100; height: 100
signal qmlSignal(variant msg)
/* MouseArea {
anchors.fill: parent
onClicked: item.qmlSignal("Hello from QML")
}*/
Rectangle{
id:sousRect
color:"red"
width:100; height:100
Button{
id:buttonTest
onClicked: {
item.qmlSignal(listCloud)
}
}
}
}
我的main.cpp
#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QQmlProperty>
#include <QQmlComponent>
#include <QDebug>
#include "myclass.h"
int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);
QQmlApplicationEngine engine;
QQmlComponent component(&engine, QUrl(QStringLiteral("qrc:/main.qml")));
QObject *object = component.create();
MyClass myClass;
QObject::connect(object, SIGNAL(qmlSignal(QVariant)),
&myClass, SLOT(cppSlot(QVariant)));
return app.exec();
}
我的myclass.h
#ifndef MYCLASS_H
#define MYCLASS_H
#include <QDebug>
#include <QString>
#include <QList>
class MyClass : public QObject
{
Q_OBJECT
public:
MyClass(QObject *parent = 0);
signals:
public slots:
void cppSlot(QVariant &msg);
};
#endif // MYCLASS_H
我的myclass.cpp
#include "myclass.h"
MyClass::MyClass(QObject *parent):
QObject(parent)
{
}
void MyClass::cppSlot(QVariant &msg){
qDebug() << "c++: bien reçu chef " << msg;
}
我不明白為什么不能在該信號中添加QVariant參數。 歡迎任何幫助:)
不要在QML和C ++之間使用引用,它們將無法工作。
無效cppSlot(QVariant & msg);
您也可以在C ++中創建Q_INVOKABLE函數,然后直接從QML調用它。 這是這樣的:
main.cpp:
#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QQmlProperty>
#include <QQmlComponent>
#include <QDebug>
#include "myclass.h"
int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);
QQmlApplicationEngine engine;
auto myobject = new MyClass(&app);
engine.rootContext()->setContextProperty(QStringLiteral("myobject"), myobject);
engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
if (engine.rootObjects().isEmpty())
{
return -1;
}
return app.exec();
}
mycass.h:
#ifndef MYCLASS_H
#define MYCLASS_H
#include <QDebug>
#include <QString>
#include <QList>
class MyClass : public QObject
{
Q_OBJECT
public:
MyClass(QObject *parent = 0);
Q_INVOKABLE void cppSlot(QVariant msg);
};
#endif // MYCLASS_H
myclass.cpp:
#include "myclass.h"
MyClass::MyClass(QObject *parent):QObject(parent){}
void MyClass::cppSlot(QVariant msg)
{
qDebug() << "c++: bien reçu chef " << msg;
}
main.qml:
import QtQuick 2.4
import QtQuick.Layouts 1.1
import Material.ListItems 0.1 as ListItem
import Material.Extras 0.1
import QtQuick.Controls 1.3 as QuickControls
import QtQuick.Controls 1.4
import Material 0.2
Window
{
visible: true
property var listCloud: ["nuage1", "nuage2", "nuage3", "nuage4"]
id: item
width: 100; height: 100
Rectangle
{
id:sousRect
color:"red"
width:100; height:100
Button
{
id:buttonTest
onClicked: myobject.cppSlot(listCloud)
}
}
}
但是,如果您想使用SIGNAL SLOTS,則QML中有Connections對象。 您的main.qml將如下所示:
Window
{
visible: true
property var listCloud: ["nuage1", "nuage2", "nuage3", "nuage4"]
id: item
width: 100; height: 100
Connections
{
target: buttonTest
onClicked: myobject.cppSlot(listCloud)
}
Rectangle
{
id:sousRect
color:"red"
width:100; height:100
Button
{
id:buttonTest
}
}
}
Q_INVOKABLE作為公共SLOT別無其他,它將通過元對象系統調用。
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