QTableView questions

[space_otter]

I'm using a QTableView and I supply headerData but the headers do not appear. The option is checked in ui editor and QHeaderView is defined. Why don't they appear?

Also, why is there a white box next to some of my data items? Can I change its contents?

[waynew]

Hey Otter - need to see some code - how are you defining the view and the header?

[space_otter]

The table's a special view for a 1D list of elements. Column #3 shows a string representation of the element, columns #1 & #2 are supposed to have buttons for deleting & moving the element to the end of the list. Stack inherits QAbstractItemModel and QList<DNumber>. DNumber has methods to parse to and from a QString.

QVariant Stack::data ( const QModelIndex & index, int role ) const {
	switch(index.column())
	{
	case 0:
		return QVariant();
	case 1:
		return QVariant();
	case 2:
		return const_cast<DNumber*>(&at(index.row()))->toString();
	}
	return QVariant();
}
 
QModelIndex Stack::index ( int row, int column, const QModelIndex & parent) const {
	return this->createIndex(row, column, parent.internalPointer());
}
 
QModelIndex Stack::parent ( const QModelIndex & index ) const {
        return QModelIndex();
}
 
int Stack::columnCount ( const QModelIndex & parent ) const {
	return 3;
}
 
int Stack::rowCount ( const QModelIndex & parent ) const {
	return this->size();
}
 
QVariant Stack::headerData ( int section, Qt::Orientation orientation, int role) const
{
    if(orientation == Qt::Horizontal)
    {
        switch(section)
        {
        case 0:
            return "Roll";
        case 1:
            return "Drop";
        case 2:
            return "Value";
        default:
            return "???";
        }
    }
    else
    {
        int size = this->size();
        if(section == size - 1)
        {
            return "X";
        }
        else if(section == size - 2)
        {
            return "Y";
        }
        else
        {
            return size - section;
        }
    }
}
 
// is a slot, the widget with the table also has a spinner connected to this to change the number of digits displayed as the value changes
void Stack::setDecimalPlaces(int i) {
    mDecimalPlaces = i;
    emit dataChanged(index(0, 0), index(size()-1, 2));
}

QVariant Stack::data ( const QModelIndex & index, int role ) const {
	switch(index.column())
	{
	case 0:
		return QVariant();
	case 1:
		return QVariant();
	case 2:
		return const_cast<DNumber*>(&at(index.row()))->toString();
	}
	return QVariant();
}

QModelIndex Stack::index ( int row, int column, const QModelIndex & parent) const {
	return this->createIndex(row, column, parent.internalPointer());
}

QModelIndex Stack::parent ( const QModelIndex & index ) const {
        return QModelIndex();
}

int Stack::columnCount ( const QModelIndex & parent ) const {
	return 3;
}

int Stack::rowCount ( const QModelIndex & parent ) const {
	return this->size();
}

QVariant Stack::headerData ( int section, Qt::Orientation orientation, int role) const
{
    if(orientation == Qt::Horizontal)
    {
        switch(section)
        {
        case 0:
            return "Roll";
        case 1:
            return "Drop";
        case 2:
            return "Value";
        default:
            return "???";
        }
    }
    else
    {
        int size = this->size();
        if(section == size - 1)
        {
            return "X";
        }
        else if(section == size - 2)
        {
            return "Y";
        }
        else
        {
            return size - section;
        }
    }
}

// is a slot, the widget with the table also has a spinner connected to this to change the number of digits displayed as the value changes
void Stack::setDecimalPlaces(int i) {
    mDecimalPlaces = i;
    emit dataChanged(index(0, 0), index(size()-1, 2));
}

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My implementation of QAbstractItemModel might not be the greatest Should I use QAbstractTableModel? That emit statement does nothing and I think it's becuase my index() is wrong.

[space_otter]

Arrg... new problem. Stack won't compile. I get this error:

'stack\Stack.h:0: Warning: No relevant classes found. No output generated.
g++ -enable-stdcall-fixup -Wl,-enable-auto-import -Wl,-enable-runtime-pseudo-reloc -Wl,-s -mthreads -Wl -Wl,-subsystem,windows -o release\Demurr.exe object_script.Demurr.Release -L"f:\Programs\Qt4.6\qt\lib" -lopengl32 -lglu32 -lgdi32 -luser32 -lmingw32 -lqtmain F:/Programs/mapm/libmapm.a -lQtOpenGL4 -lQtGui4 -lQtCore4
mingw32-make[1]: Leaving directory `G:/Documents/Projects/Demurr2'
mingw32-make: Leaving directory `G:/Documents/Projects/Demurr2'
./release\Stack.o:Stack.cpp:(.text+0x2e0): undefined reference to `vtable for Stack'
./release\Stack.o:Stack.cpp:(.text+0x328): undefined reference to `vtable for Stack'
./release\Stack.o:Stack.cpp:(.text+0x36c): undefined reference to `vtable for Stack'
./release\Stack.o:Stack.cpp:(.text+0x3d4): undefined reference to `vtable for Stack'
./release\Stack.o:Stack.cpp:(.text+0x4bc): undefined reference to `vtable for Stack'
collect2: ld returned 1 exit status

'stack\Stack.h:0: Warning: No relevant classes found. No output generated.
g++ -enable-stdcall-fixup -Wl,-enable-auto-import -Wl,-enable-runtime-pseudo-reloc -Wl,-s -mthreads -Wl -Wl,-subsystem,windows -o release\Demurr.exe object_script.Demurr.Release -L"f:\Programs\Qt4.6\qt\lib" -lopengl32 -lglu32 -lgdi32 -luser32 -lmingw32 -lqtmain F:/Programs/mapm/libmapm.a -lQtOpenGL4 -lQtGui4 -lQtCore4
mingw32-make[1]: Leaving directory `G:/Documents/Projects/Demurr2'
mingw32-make: Leaving directory `G:/Documents/Projects/Demurr2'
./release\Stack.o:Stack.cpp:(.text+0x2e0): undefined reference to `vtable for Stack'
./release\Stack.o:Stack.cpp:(.text+0x328): undefined reference to `vtable for Stack'
./release\Stack.o:Stack.cpp:(.text+0x36c): undefined reference to `vtable for Stack'
./release\Stack.o:Stack.cpp:(.text+0x3d4): undefined reference to `vtable for Stack'
./release\Stack.o:Stack.cpp:(.text+0x4bc): undefined reference to `vtable for Stack'
collect2: ld returned 1 exit status

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I'm sure MOC is being invoked, it's compiliing moc_Stack.cpp. What is going on? This error has popped up before randomly and I fixed it by adding the file to the pro file, and it's definitely in the pro file. Here is Stack.h:

/*
 * Stack.h
 *
 *  Created on: Feb 27, 2010
 *      Author: Eric
 */
 
#include <QAbstractItemModel>
#include <QTableView>
#include "math/DNumber.h"
#include "stacktabwidget.h"
 
#ifndef STACK_H_
#define STACK_H_
 
class Stack : public QAbstractItemModel, public QList<DNumber> {
    Q_OBJECT
public:
        Stack(QTableView *stw, int dplaces, int accuracy);
	~Stack();
 
	// functions overridden from QAbstractItemModel
	QVariant data ( const QModelIndex & index, int role = Qt::DisplayRole ) const;
	QModelIndex index ( int row, int column, const QModelIndex & parent = QModelIndex() ) const;
	QModelIndex parent ( const QModelIndex & index ) const;
	int columnCount ( const QModelIndex & parent = QModelIndex() ) const;
	int rowCount ( const QModelIndex & parent = QModelIndex() ) const;
        QVariant headerData ( int section, Qt::Orientation orientation, int role = Qt::DisplayRole ) const;
 
private:
	// internal settings
	int mDecimalPlaces;
	int mAccuracy;
        QTableView *mTableView;
 
        // get & set
public slots:
        void setDecimalPlaces(int i);
        void setAccuracy(int i);
};
 
#endif /* STACK_H_ */

/*
 * Stack.h
 *
 *  Created on: Feb 27, 2010
 *      Author: Eric
 */

#include <QAbstractItemModel>
#include <QTableView>
#include "math/DNumber.h"
#include "stacktabwidget.h"

#ifndef STACK_H_
#define STACK_H_

class Stack : public QAbstractItemModel, public QList<DNumber> {
    Q_OBJECT
public:
        Stack(QTableView *stw, int dplaces, int accuracy);
	~Stack();

	// functions overridden from QAbstractItemModel
	QVariant data ( const QModelIndex & index, int role = Qt::DisplayRole ) const;
	QModelIndex index ( int row, int column, const QModelIndex & parent = QModelIndex() ) const;
	QModelIndex parent ( const QModelIndex & index ) const;
	int columnCount ( const QModelIndex & parent = QModelIndex() ) const;
	int rowCount ( const QModelIndex & parent = QModelIndex() ) const;
        QVariant headerData ( int section, Qt::Orientation orientation, int role = Qt::DisplayRole ) const;

private:
	// internal settings
	int mDecimalPlaces;
	int mAccuracy;
        QTableView *mTableView;

        // get & set
public slots:
        void setDecimalPlaces(int i);
        void setAccuracy(int i);
};

#endif /* STACK_H_ */

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I've implemented all the functions.

[space_otter]

Took out #include "stacktabwidget.h" and it works again. But my original question remains.

[norobro]

Try this:

QVariant Stack::headerData ( int section, Qt::Orientation orientation, int role) const
{
 
    if(role != Qt::DisplayRole) return QVariant();  // only run your code for the display role
 
    if(orientation == Qt::Horizontal)
   {
. . . .
. . . .

QVariant Stack::headerData ( int section, Qt::Orientation orientation, int role) const
{

    if(role != Qt::DisplayRole) return QVariant();  // only run your code for the display role

    if(orientation == Qt::Horizontal)
   {
. . . .
. . . .

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[space_otter]

Sweet! That worked.

The white boxes are still there. What are they for?

[norobro]

Try putting the same statement in data().