error: no matching function for call to ‘QFrame::QFrame(MainWindow&)’

Anosema

Hello,
I'm new to C++ but I used to do a lot of PyQt.
I need to subclass a QTreeWidgetItem which will own a QFrame which has a subclassed QMainWindow as parent. Here is the full code:

main.cpp

#include <QApplication>
#include "window.h"
#include <iostream>

struct MainWindow;
struct WritingTab;

WritingTab::WritingTab(MainWindow *par) : QTreeWidgetItem()
{
    writeFrame = new QFrame(*par);
    titleEntry = new QLineEdit(writeFrame);
    noteEntry = new QPlainTextEdit(writeFrame);
    clearButton = new QPushButton(writeFrame);
    writeFrame->setGeometry(100, 0, writeFrame->width() - 100, writeFrame->height());
}

MainWindow::MainWindow() : QMainWindow()
{
    tabVector = {new WritingTab(this)};
    treeWidget = new QTreeWidget(this);
    treeWidget->addTopLevelItem(tabVector.at(0));
    treeWidget->setColumnCount(1);
    setStyleSheet("*{border: 1px solid red;}");
    setGeometry(10, 10, 500, 500);
    show();
}
void MainWindow::resizeEvent(QResizeEvent *event)
{
    treeWidget->setGeometry(0, 0, 100, height());
    event->accept();
};

int main(int argc, char **argv)
{
    QApplication app(argc, argv);
    MainWindow window;
    return app.exec();
}

and window.h

#ifndef WINDOW_H
#define WINDOW_H
#include <QPlainTextEdit>
#include <QPushButton>
#include <QMainWindow>
#include <QTreeWidget>
#include <QTreeWidgetItem>
#include <QLineEdit>
#include <QFrame>
#include <iostream>

struct MainWindow;
struct WritingTab;

class WritingTab : public QTreeWidgetItem
{
public:
    explicit WritingTab(MainWindow *par);
    QFrame *writeFrame;
    QLineEdit *titleEntry;
    QPlainTextEdit *noteEntry;
    QPushButton *clearButton;

private:
signals:
public slots:
};
class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    explicit MainWindow();
    QList<WritingTab *> tabVector;
    QTreeWidget *treeWidget;
    void resizeEvent(QResizeEvent *event);

private:
signals:
public slots:
};
#endif

But I have an error while compiling:

main.cpp: In constructor ‘WritingTab::WritingTab(MainWindow*)’:
main.cpp:10:33: error: no matching function for call to ‘QFrame::QFrame(MainWindow&)’
writeFrame = new QFrame(*par);

I don't really know how to fix it so any help is welcomed :)

jsulm

@Anosema said in error: no matching function for call to ‘QFrame::QFrame(MainWindow&)’:

writeFrame = new QFrame(*par);

Should be

writeFrame = new QFrame(par);

as it takes a pointer...

Christian Ehrlicher

@Anosema said in error: no matching function for call to ‘QFrame::QFrame(MainWindow&)’:

I don't really know how to fix it so any help is welcomed :)

QFrame needs a pointer as parent, no object.

Anosema

Thanks I did remove the * from

writeFrame = new QFrame(*par);

and the frame now show. But, when I try this line, the compiler says the object returned by parent() is a QObject, not the MainWindow

writeFrame->setGeometry(100, 0, writeFrame->parent()->width() - 100, writeFrame->parent()->height());

Christian Ehrlicher

@Anosema said in error: no matching function for call to ‘QFrame::QFrame(MainWindow&)’:

says the object returned by parent() is a QObject, not the MainWindow

And it's right...: https://doc.qt.io/qt-5/qobject.html#parent

You maybe want https://doc.qt.io/qt-5/qwidget.html#parentWidget

Anosema

@Christian-Ehrlicher Oh thanks, I thought it would behave like in PyQt but I was wrong, thanks again.

Christian Ehrlicher

No, python and c++ are two completely different languages and concepts.