[Solved] Error: Invalid use of member (...) in static member function
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I have a UI window created in UI Designer called MonitorWindow. It has a child widget called DualDial. Basically what I'm doing is drawing 2 dials on the MonitorWindow. One is like a second hand, and the other is like a minute hand on a clock. These dials are updated with a timer (that's called by DualDial) that goes off every 100ms. All of this works fine. On the MonitorWindow UI, there's also a text label, timeLabel, that displays the current time, and I want to update that label with the timer that's running in DualDial. I've connected a signal, timeChanged, to a slot called UpdateTimeSlot in MonitorWindow. Here's the monitorwindow.h file:
@
namespace Ui {
class MonitorWindow;
}
class MonitorWindow : public QWidget
{
Q_OBJECT
public:
explicit MonitorWindow(QWidget *parent = 0);
~MonitorWindow();
Ui::MonitorWindow *ui;
public slots:
static void UpdateTimeSlot();
};
@
Then, in the MonitorWindow constructor, I instatiate the child widget called DualDial:
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DualDial *dualdial = new DualDial(this);
@
In the DualDial constructor, I connect the signal to the slot:
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connect(this, timeChanged(), parent, MonitorWindow::UpdateTimeSlot());
@
The timeChanged signal is emitted inside the timer function for DualDial, so this should call MonitorWindow::UpdateTimeSlot. Inside that function I create a string called timeStr and then just update the timeLabel in the UI with the new string:
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ui->timeLabel->setText(timeStr);
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When I try to compile, it gives me the error: invalid use of member 'MonitorWindow::ui' in static member function. It points to the line of code above. What am I doing wrong?
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Why you want ahve static slot?
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When the UpdateTimeSlot wasn't static, I got the error: "cannot call member function 'MonitorWindow::UpdateTimeSlot()' without object" when I tried to connect the signal and the slot:
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connect(this, timeChanged(), parent, MonitorWindow::UpdateTimeSlot());
@
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I guess parent is pointer to MonitorWindow instance. right?
When you need:@connect(this, SIGNAL(timeChanged()), parent, SLOT(UpdateTimeSlot()));@
and remove static
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It then tells me that UpdateTimeSlot was not declared in this scope. Here's the beginning of the dualdial.cpp file with the constructor:
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#include "dualdial.h"
#include "global.h"
#include "monitorwindow.h"DualDial::DualDial(QWidget *parent) :
QWidget(parent)
{
move(465, 100);
resize(400, 150);
connect(this, timeChanged(), parent, UpdateTimeSlot());
QTimer *timer = new QTimer(this);
connect(timer, SIGNAL(timeout()), this, SLOT(update()));
timer->start(10);
}
@
And if you need it, here's the dualdial.h file:
@
#include <QtGui>class DualDial : public QWidget
{
Q_OBJECT
public:
explicit DualDial(QWidget *parent = 0);
signals:
void timeChanged();
protected:
void paintEvent(QPaintEvent *);
};
@
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At first glance, in line 10, you need to wrap your signal and slot names in SIGNAL and SLOT macros.
@
connect(this, SIGNAL(timeChanged()), parent, SLOT(UpdateTimeSlot()));
@There may be other issues, but this one is important.
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And here I thought it was some heavy C++ issue that I wouldn't understand. :o) It was right there in front of me!! Thanks both of you for your help!
