Can’t connect the signal to the value of the ProgressBar(would crash)

[stereoMatching]

.hpp

#ifndef PROGRESSCONNECTION_HPP
    #define PROGRESSCONNECTION_HPP
 
    #include <QObject>
 
    class progressConnection : public QObject
    {
        Q_OBJECT
        Q_PROPERTY(int progressMaximum READ progressMaximum WRITE setProgressMaximum NOTIFY progressMaximumChanged)
        Q_PROPERTY(int progressValue READ progressValue WRITE setProgressValue NOTIFY progressValueChanged)
    public:
        explicit progressConnection(QObject *parent = 0);
 
        Q_INVOKABLE void addProgressValue();
 
        int progressMaximum() const;
        int progressValue() const;
 
        void setProgressMaximum(int value);
        void setProgressValue(int value);
 
    signals:
        void progressMaximumChanged();
        void progressValueChanged();
 
    private:
        void addProgressValueImpl();
 
    private:
        QMutex mutex_;
 
        int progressMaximum_;
        int progressValue_;
 
        int size_;
    };
 
    #endif // PROGRESSCONNECTION_HPP

#ifndef PROGRESSCONNECTION_HPP
    #define PROGRESSCONNECTION_HPP
     
    #include <QObject>
     
    class progressConnection : public QObject
    {
        Q_OBJECT
        Q_PROPERTY(int progressMaximum READ progressMaximum WRITE setProgressMaximum NOTIFY progressMaximumChanged)
        Q_PROPERTY(int progressValue READ progressValue WRITE setProgressValue NOTIFY progressValueChanged)
    public:
        explicit progressConnection(QObject *parent = 0);
     
        Q_INVOKABLE void addProgressValue();
     
        int progressMaximum() const;
        int progressValue() const;
     
        void setProgressMaximum(int value);
        void setProgressValue(int value);
       
    signals:
        void progressMaximumChanged();
        void progressValueChanged();
     
    private:
        void addProgressValueImpl();
     
    private:
        QMutex mutex_;
     
        int progressMaximum_;
        int progressValue_;
     
        int size_;
    };
     
    #endif // PROGRESSCONNECTION_HPP

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.cpp

#include <QDebug>
 
    #include "progressConnection.hpp"
 
    progressConnection::progressConnection(QObject *parent) :
        QObject(parent),
        progressMaximum_(1),
        progressValue_(0),
        size_(100000)
    {      
    }
 
    void progressConnection::addProgressValue()
    {
        setProgressMaximum(size_);
        setProgressValue(0);
 
        addProgressValueImpl();
    }
 
    int progressConnection::progressMaximum() const
    {
        return progressMaximum_;
    }
 
    int progressConnection::progressValue() const
    {
        return progressValue_;
    }
 
    void progressConnection::setProgressMaximum(int value)
    {
        if(value != progressMaximum_){
            progressMaximum_ = value;
            qDebug()<<"progress maximum = "<<progressMaximum_;
            emit progressMaximumChanged();
        }
    }
 
    void progressConnection::setProgressValue(int value)
    {
        if(value != progressValue_){
            progressValue_ = value;
            //qDebug()<<"progress value = "<<progressValue_;
            emit progressValueChanged();
        }
    }
 
    void progressConnection::addProgressValueImpl()
    {
        for(int i = 0; i != size_; ++i){
            setProgressValue(i);
        }
    }

#include <QDebug>
     
    #include "progressConnection.hpp"
     
    progressConnection::progressConnection(QObject *parent) :
        QObject(parent),
        progressMaximum_(1),
        progressValue_(0),
        size_(100000)
    {      
    }
     
    void progressConnection::addProgressValue()
    {
        setProgressMaximum(size_);
        setProgressValue(0);
     
        addProgressValueImpl();
    }
     
    int progressConnection::progressMaximum() const
    {
        return progressMaximum_;
    }
     
    int progressConnection::progressValue() const
    {
        return progressValue_;
    }
     
    void progressConnection::setProgressMaximum(int value)
    {
        if(value != progressMaximum_){
            progressMaximum_ = value;
            qDebug()<<"progress maximum = "<<progressMaximum_;
            emit progressMaximumChanged();
        }
    }
     
    void progressConnection::setProgressValue(int value)
    {
        if(value != progressValue_){
            progressValue_ = value;
            //qDebug()<<"progress value = "<<progressValue_;
            emit progressValueChanged();
        }
    }
     
    void progressConnection::addProgressValueImpl()
    {
        for(int i = 0; i != size_; ++i){
            setProgressValue(i);
        }
    }

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main.cpp

#include <QApplication>
    #include <QQmlEngine>
    #include <QQuickView>
    #include <QtQml>
 
    #include "progressConnection.hpp"
 
    int main(int argc, char *argv[])
    {
        QApplication app(argc, argv);  
 
        qmlRegisterType<progressConnection>("Test", 1, 0, "ProgressConnection");
 
        QQmlApplicationEngine engine(QUrl("qrc:/main.qml"));  
        QObject *topLevel = engine.rootObjects().value(0);
        QQuickWindow *window = qobject_cast<QQuickWindow *>(topLevel);
        if (!window) {
            qWarning("Error: Your root item has to be a Window.");
            return -1;
        }
        window->show();
 
        return app.exec();
    }

#include <QApplication>
    #include <QQmlEngine>
    #include <QQuickView>
    #include <QtQml>
     
    #include "progressConnection.hpp"
     
    int main(int argc, char *argv[])
    {
        QApplication app(argc, argv);  
     
        qmlRegisterType<progressConnection>("Test", 1, 0, "ProgressConnection");
     
        QQmlApplicationEngine engine(QUrl("qrc:/main.qml"));  
        QObject *topLevel = engine.rootObjects().value(0);
        QQuickWindow *window = qobject_cast<QQuickWindow *>(topLevel);
        if (!window) {
            qWarning("Error: Your root item has to be a Window.");
            return -1;
        }
        window->show();
     
        return app.exec();
    }

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main.qml

import QtQuick 2.1
    import QtQuick.Controls 1.0
    import QtQuick.Dialogs 1.0
    import QtQuick.Layouts 1.0
 
    import Test 1.0
 
    ApplicationWindow{
        id: root
 
        title: "Color Correction"
 
        color: syspal.window
        width: 1450
        height: 750
        minimumHeight: 750
        minimumWidth: 1400
 
        SystemPalette {id: syspal}
 
        Component{
            id: compProgressTest
 
            ProgressConnection{
 
            }
        }
 
        Loader{
            id: loader
 
            sourceComponent: null
 
            onStatusChanged: {
                if(loader.status == Loader.Ready){
                    console.log("Ready")
                }
            }
        }
 
        Row{
            anchors.fill: parent
 
            Button{
                text: "reload"
                onClicked: {
                    loader.sourceComponent = null
                    loader.sourceComponent = compProgressTest
                }
            }
 
            Button{
                text: "run"
                onClicked: {
                    if(loader.status == Loader.Ready){
                        loader.item.addProgressValue()
                    }
                }
            }
 
            ProgressBar{
                id: progressBar
 
                maximumValue: loader.status == Loader.Ready ? loader.item.progressMaximum : 1
                value: loader.status == Loader.Ready ? loader.item.progressValue : 0
 
                onValueChanged: {
                    console.log("progress bar value = " + progressBar.value)
                }
            }
        }
 
    }

import QtQuick 2.1
    import QtQuick.Controls 1.0
    import QtQuick.Dialogs 1.0
    import QtQuick.Layouts 1.0
     
    import Test 1.0
     
    ApplicationWindow{
        id: root
     
        title: "Color Correction"
     
        color: syspal.window
        width: 1450
        height: 750
        minimumHeight: 750
        minimumWidth: 1400
     
        SystemPalette {id: syspal}
     
        Component{
            id: compProgressTest
     
            ProgressConnection{
     
            }
        }
     
        Loader{
            id: loader
     
            sourceComponent: null
     
            onStatusChanged: {
                if(loader.status == Loader.Ready){
                    console.log("Ready")
                }
            }
        }
     
        Row{
            anchors.fill: parent
     
            Button{
                text: "reload"
                onClicked: {
                    loader.sourceComponent = null
                    loader.sourceComponent = compProgressTest
                }
            }
     
            Button{
                text: "run"
                onClicked: {
                    if(loader.status == Loader.Ready){
                        loader.item.addProgressValue()
                    }
                }
            }
     
            ProgressBar{
                id: progressBar
     
                maximumValue: loader.status == Loader.Ready ? loader.item.progressMaximum : 1
                value: loader.status == Loader.Ready ? loader.item.progressValue : 0
     
                onValueChanged: {
                    console.log("progress bar value = " + progressBar.value)
                }
            }
        }
     
    }

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The codes would crash, have no idea what kind of mistakes I do

[anda_skoa]

Try something simpler first, e.g. just an ApplicationWindow and the custom type, no loader, etc.

Cheers,
_

[stereoMatching]

The other experiment, I Remove all of my Loader codes(but do not make the ProgressBar as context property).

I don’t know why, after I replace the Loader codes with

ProgressConnection{
            id: progressConnection
        }

ProgressConnection{
            id: progressConnection
        }

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The program wouldn’t crash again weather it is single thread or multi-thread, pretty weird
Do the loader of Qt5.1 has some bugs?Or my mistakes?