如何将通过 C++ 中的另一个类添加到 ListView、QML 的数据显示出来?

I need to present all the data in the QLinkedList container (this was given by the task). I created two classes, DataObject for my delegates in ListView, Glav for container with DataObject objects. I have a button on which I add data to the container (the addItem function in the Glav class). The data is added but not displayed in the ListView. How to display them? I tried it through signals, it didn't work. Here is the complete code of the project.

main.cpp

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QStringListModel>
#include <QQmlContext>
#include <QLinkedList>
#include <QQuickView>

#include <container.h>
#include <dataobject.h>
#include "glav.h"
//#include <container.cpp>

int main(int argc, char *argv[])
{
#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
#endif

    QGuiApplication app(argc, argv);
    QQmlApplicationEngine engine;
    qmlRegisterUncreatableType<tile::Glav>( "Tile", 1, 0, "DataItem", "interface" );

    qmlRegisterType<tile::Glav>( "Tile", 1, 0, "Glav");

    const QUrl url(QStringLiteral("qrc:/main.qml"));
    QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
                     &app, [url](QObject *obj, const QUrl &objUrl) {
        if (!obj && url == objUrl)
            QCoreApplication::exit(-1);
    }, Qt::QueuedConnection);
    engine.load(url);

    return app.exec();
}

main.qml

import QtQuick 2.12
import QtQuick.Controls 2.5
//import App 1.0
import Tile 1.0

ApplicationWindow {
    width: 640
    height: 480
    visible: true
    title: qsTr("Scroll")

//    Container {
//        id: container
//    }

    Glav {
        id: glav
    }


    Row {
        id: buttons
        spacing: 20
        padding: 10
        anchors.horizontalCenter: parent.horizontalCenter

        RoundButton {
            padding: 20
            text: "add item"
            onClicked: {

                glav.addItem()
                listView.currentIndex = -1
            }

    }

    Connections{
    target: myModelObjectWhichWasSetAsContextProperty
    onRowsInserted: console.log("rows were inserted")
    }

    ScrollView {
        anchors.fill: parent
        anchors.topMargin: buttons.implicitHeight + 10
        ListView {
            id: listView
            width: parent.width
            model: glav.list
            //required model
            delegate: Text {
                property var d
                d: model.modelData.id
                text: model.modelData.name
            }
            removeDisplaced: Transition {
                NumberAnimation { properties: "x,y"; duration: 100; easing.type: Easing.InOutQuad }
            }
}
}
}

数据对象.h

#ifndef DATAOBJECT_H
#define DATAOBJECT_H

#include <QObject>
namespace tile {
class DataObject : public QObject
{
    Q_OBJECT

    Q_PROPERTY(QString name READ name WRITE setName NOTIFY changed)
    Q_PROPERTY(QString color READ color WRITE setColor NOTIFY changed)
    Q_PROPERTY(int id READ id WRITE setId NOTIFY changed)

public:
    explicit DataObject(QString name = "Wana", QString color = "red", int id = 1, QObject *parent = nullptr);

    QString name();
    void setName(const QString &name);

    QString color();
    void setColor(const QString &color);

    int id() const;
    void setId(int id);

signals:

    void changed();

private:

    QString m_name;
    QString m_color;
    int m_id;

};
}
#endif // DATAOBJECT_H

数据对象.cpp

#include "dataobject.h"

#include <QDebug>
namespace tile {
DataObject::DataObject(QString name, QString color, int id, QObject* parent) :
    QObject(parent)
    , m_name (name)
    , m_color (color)
    , m_id (id)
{
    //new DataObject();
    qDebug() << m_name;
    //emit changed();
}

QString DataObject::name()
{
    return m_name;
}

void DataObject::setName(const QString &name)
{
    m_name = name;
    qDebug() << m_name;
    emit changed();
}

QString DataObject::color()
{
    return m_color;
}

void DataObject::setColor(const QString &color)
{
    m_color = color;
    emit changed();
}

int DataObject::id() const
{
    return m_id;
}

void DataObject::setId(int id)
{
    m_id = id;
    emit changed();
}
}

glav.h

#ifndef GLAV_H
#define GLAV_H

#include <QObject>
#include <QLinkedList>

namespace tile {
class Glav : public QObject
{
    Q_OBJECT

    Q_PROPERTY( QLinkedList<QObject *> list READ list CONSTANT )
public:
    explicit Glav(QObject *parent = nullptr);

    //QLinkedList<QObject *> list();
    //void setList(const QLinkedList<QObject *> &list);

    Q_INVOKABLE QLinkedList<QObject *> pollist();
    Q_INVOKABLE void addItem();
//    Q_INVOKABLE QVariant pol();


signals:
    void changed();

private:
    QLinkedList<QObject *> m_list;
    QLinkedList<QObject *> list();

};
}
#endif // GLAV_H

glav.cpp

#include "glav.h"
#include "dataobject.h"

#include <QDebug>
#include <QAbstractListModel>

namespace tile {
Glav::Glav(QObject *parent) : QObject(parent)
{
    QLinkedList<QObject *> dataList = {
            new DataObject("Item 1", "red"),
            new DataObject("Item 2", "green"),
            new DataObject("Item 3", "blue"),
            new DataObject("Item 9", "yellow")
        };
    m_list << dataList;
    QVariant::fromValue(m_list);

}

QLinkedList<QObject *> Glav::list()
{
    return m_list;
}

//void Glav::setList(const QLinkedList<QObject *> &list)
//{
//    m_list = list;
//}


//QVariant Glav::pol(){

//     QVariant re = QVariant::fromValue(m_list);
//    return re;
//}


QLinkedList<QObject *> Glav::pollist()
{
    //qDebug() << QVariant::fromValue(m_list);
    //QLinkedList<QObject *> f = m_list;
    //QVariant::fromValue(m_list);
    //qDebug() <<m_list;
    return m_list;
}

void Glav::addItem()
{
    qDebug() << m_list.count();
    m_list << new DataObject();
    qDebug() << m_list.count();
    emit changed();
}
}

推荐答案

你的 Glav 类有一个 changed() 信号，但它什么也没做，因为你的 list 属性是常量(Q_PROPERTY(QLinkedList list READ list CONSTANT))

Q_PROPERTY(QLinkedList<QObject*> list READ list NOTIFY changed)