Problem with function "setCentralWidget"

[Creatorczyk]

Hi,

I wrote some clas named "Monitor":

monitor.h

class Monitor : public QGridLayout
{
    Q_OBJECT
public:
    Monitor(QWidget *parent = 0);

public slots:
    void setValue(float value);
};

monitor.cpp

Monitor::Monitor(QWidget *parent)
    :QGridLayout(parent)
{
}

But when I try seet this widet in mainwindow with "setCentralWidget()" method I got some error:

Monitor *monitor = new Monitor(this);
setCentralWidget(monitor);

Error:

error: no matching function for call to 'MainWindow::setCentralWidget(Monitor*&)'
no known conversion for argument 1 from 'Monitor*' to 'QWidget*'

How colud I fix that?

[JonB]

@Creatorczyk said in Problem with function "setCentralWidget":

class Monitor : public QGridLayout

But when I try seet this widet
no known conversion for argument 1 from 'Monitor*' to 'QWidget*'

As the error message tells you. Your Monitor is a QLayout not a QWidget, so you can't call setCentralWidget() on it, as the name suggests.

You could set an empty QWidget on QMainWindow::setCentralWidget(), and then set Monitor as that widget's layout, if that is what you are wanting to do. But I am unconvinced as to what you are trying to do with your Monitor: given that it is a QGridLayout, what is its setValue() intended to do, layouts/grid layouts don't have "values"?