How to take window from QWorkspace?

[8Observer8]

Hi,

I try to take window from QWorkspace. But it doesn't work:

m_tablePanel = (TabelPanel *)(workspace->windowList()).at(0);

m_tablePanel = (TabelPanel *)(workspace->windowList()).at(0);

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Thank you!

[wysota]

Please define what you mean by "it doesn't work".

[8Observer8]

I cannot update my Plot.

42.jpg

I'm a little ashamed for my code. But this is my first MDI program.

There is a little code:

m_tablePanel = (TabelPanel *)(workspace->windowList()).at(0);
    m_plotPanel = (PlotPanel *)(workspace->windowList()).at(1);
 
    connect(m_tablePanel, SIGNAL(itemChanged(QStandardItem *)), this, SLOT(updatePanel(QStandardItem*)));

m_tablePanel = (TabelPanel *)(workspace->windowList()).at(0);
    m_plotPanel = (PlotPanel *)(workspace->windowList()).at(1);

    connect(m_tablePanel, SIGNAL(itemChanged(QStandardItem *)), this, SLOT(updatePanel(QStandardItem*)));

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void MainWindow::updatePanel(QStandardItem *item)
{
    m_plotPanel->updatePanel(model);
}

void MainWindow::updatePanel(QStandardItem *item)
{
    m_plotPanel->updatePanel(model);
}

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[wysota]

Maybe you can't update your plot but it doesn't mean the method doesn't work. Especially that you have an ugly C cast instead of qobject_cast or something similar. How do you know that the first item in the list is an instance of TablePanel and the second one is an instance of PlotPanel?

[8Observer8]

I want to take instance of TablePanel and PlotPanel from workspace. I don't know how to do it.

It's doesn't work:

m_tablePanel = qobject_cast<TabelPanel *>((workspace->windowList()).at(0));
m_plotPanel = qobject_cast<PlotPanel *>((workspace->windowList()).at(1));

m_tablePanel = qobject_cast<TabelPanel *>((workspace->windowList()).at(0));
m_plotPanel = qobject_cast<PlotPanel *>((workspace->windowList()).at(1));

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How do you know that the first item in the list is an instance of TablePanel and the second one is an instance of PlotPanel?

I added the Table then the Plot.

workspace->addWindow(tablePanel);
workspace->addWindow(plotPanel);

workspace->addWindow(tablePanel);
workspace->addWindow(plotPanel);

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Slot of MainWindow updatePanel() doesn't work.

connect(m_tablePanel, SIGNAL(itemChanged(QStandardItem *)), this, SLOT(updatePanel(QStandardItem*)));

connect(m_tablePanel, SIGNAL(itemChanged(QStandardItem *)), this, SLOT(updatePanel(QStandardItem*)));

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[wysota]

I want to take instance of TablePanel and PlotPanel from workspace. I don't know how to do it.

It's doesn't work:

m_tablePanel = qobject_cast<TabelPanel *>((workspace->windowList()).at(0));
m_plotPanel = qobject_cast<PlotPanel *>((workspace->windowList()).at(1));

m_tablePanel = qobject_cast<TabelPanel *>((workspace->windowList()).at(0));
m_plotPanel = qobject_cast<PlotPanel *>((workspace->windowList()).at(1));

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Define "doesn't work". Does the program crash or do you get a result different than what you expected to get?

Slot of MainWindow updatePanel() doesn't work.

The slot doesn't get called or it behaves differently to what you expected?

[8Observer8]

I set a breakpoint in updatePanel() SLOT

void MainWindow::updatePanel(QStandardItem *item)
{
    m_plotPanel->updatePanel(model);
}

void MainWindow::updatePanel(QStandardItem *item)
{
    m_plotPanel->updatePanel(model);
}

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[wysota]

You set a breakpoint and?

[8Observer8]

You set a breakpoint and?

Then I change value in the table. But nothing happens.

[wysota]

Apparently your signal-slot connection is invalid.

TablePanel class is unlikely to have a signal itemChanged() carrying a QStandardItem pointer unless you added such signal to the class yourself.

[8Observer8]

Thanks! Now the breakpoint works.

connect(model, SIGNAL(itemChanged(QStandardItem *)), this, SLOT(updatePanel(QStandardItem*)));

connect(model, SIGNAL(itemChanged(QStandardItem *)), this, SLOT(updatePanel(QStandardItem*)));

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But the Plot is not redrawn.

plotpanel.cpp

#include "plotpanel.h"
#include <QHBoxLayout>
#include <QDebug>
#include <qwt_plot_curve.h>
#include <qwt_symbol.h>
 
PlotPanel::PlotPanel(QWidget *parent) :
    QDialog(parent)
{
    plot = new QwtPlot;
 
    QHBoxLayout *mainLayout = new QHBoxLayout;
 
    mainLayout->addWidget(plot);
 
    this->setLayout(mainLayout);
}
 
void PlotPanel::updatePanel(QStandardItemModel *model)
{
    plot->setAxisScale(QwtPlot::yLeft, 0.0, 10);
    plot->setAxisScale(QwtPlot::xBottom, 0.0, 10);
 
    QwtPlotCurve *curve = new QwtPlotCurve;
    curve->setTitle(tr("Points"));
    curve->setPen(QPen(Qt::blue, 4));
    curve->setRenderHint(QwtPlotItem::RenderAntialiased, true);
 
    QwtSymbol *symbol = new QwtSymbol(QwtSymbol::Ellipse, QBrush(Qt::yellow),
                                      QPen(Qt::red, 2), QSize(8, 8));
    curve->setSymbol(symbol);
 
    QPolygonF points;
 
    double x, y;
    for (int row = 0; row < model->rowCount(); row++) {
        QModelIndex index = model->index(row, 0);
        x = model->data(index).toDouble();
 
        index = model->index(row, 1);
        y = model->data(index).toDouble();
 
        points << QPointF(x, y);
    }
 
    curve->setSamples(points);
    curve->attach(plot);
 
//    this->update();
}

#include "plotpanel.h"
#include <QHBoxLayout>
#include <QDebug>
#include <qwt_plot_curve.h>
#include <qwt_symbol.h>

PlotPanel::PlotPanel(QWidget *parent) :
    QDialog(parent)
{
    plot = new QwtPlot;

    QHBoxLayout *mainLayout = new QHBoxLayout;

    mainLayout->addWidget(plot);

    this->setLayout(mainLayout);
}

void PlotPanel::updatePanel(QStandardItemModel *model)
{
    plot->setAxisScale(QwtPlot::yLeft, 0.0, 10);
    plot->setAxisScale(QwtPlot::xBottom, 0.0, 10);

    QwtPlotCurve *curve = new QwtPlotCurve;
    curve->setTitle(tr("Points"));
    curve->setPen(QPen(Qt::blue, 4));
    curve->setRenderHint(QwtPlotItem::RenderAntialiased, true);

    QwtSymbol *symbol = new QwtSymbol(QwtSymbol::Ellipse, QBrush(Qt::yellow),
                                      QPen(Qt::red, 2), QSize(8, 8));
    curve->setSymbol(symbol);

    QPolygonF points;

    double x, y;
    for (int row = 0; row < model->rowCount(); row++) {
        QModelIndex index = model->index(row, 0);
        x = model->data(index).toDouble();

        index = model->index(row, 1);
        y = model->data(index).toDouble();

        points << QPointF(x, y);
    }

    curve->setSamples(points);
    curve->attach(plot);

//    this->update();
}

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[wysota]

I don't see you calling replot() on the plot anywhere.

[8Observer8]

Thanks! Thanks! Thanks!

There is an another problem. I wanna see the new plot. How to delete the old plot?

43.png

[wysota]

Why not reuse the old curve instead?

[8Observer8]

Maybe I must delete the old curve? How to do it? I don't understand...

[wysota]

If you want to remove the old curve then detach it from the plot and delete it.

[8Observer8]

How to get the old curve?

[wysota]

You can store it in some member variable and then retrieve it later when you need it.

[8Observer8]

Nice! It works! Thank you much

44.png

This program is still left unfinished. But it may be useful for someone.

[8Observer8]

I made a loading (saving) table from (to) a xml-file:

Table.xml

<Table nrows="5" ncols="2">
<point x="0.02" y="0.33"/>
<point x="0.56" y="1.12"/>
<point x="2.22" y="2.33"/>
<point x="6.23" y="4.87"/>
<point x="9.55" y="8.23"/>
</Table>

45.png