Qtableview set background color to some columns

[n-2204]

I have 3 Qtableview with different no. of rows and columns. I need to set column color to 2-3 column in each Table if new row is added then color should be added.
How to do that one way is using delegate any other way to set column color ?
Thanks in advance

[mrjj]

Hi
Yes you can also set via Qt::BackgroundRole either via setData
or via your customs models data function if you have a custom model.

[SGaist]

Hi,

In addition to @mrjj, QIdentityProxyModel is also a solution.

[VRonin]

While the answers above are perfectly valid I think in your case it might be easier to just use a delegate:

class BackgroundBrushDelegate : public QStyledItemDelegate{
    Q_OBJECT
    Q_PROPERTY(QBrush backgroundBrush READ backgroundBrush WRITE setBackgroundBrush NOTIFY backgroundBrushChanged)
    Q_DISABLE_COPY(BackgroundBrushDelegate)
public:
    explicit BackgroundBrushDelegate(QObject *parent = nullptr)
        : QStyledItemDelegate(parent)
    {}
    BackgroundBrushDelegate(const QBrush& brush, QObject *parent = nullptr)
        : QStyledItemDelegate(parent)
        , m_backgroundBrush(brush)
    {}
    const QBrush& backgroundBrush() const { return m_backgroundBrush; }
    void setBackgroundBrush(const QBrush& brush)
    {
        if(m_backgroundBrush==brush)
            return;
        m_backgroundBrush=brush;
        backgroundBrushChanged(m_backgroundBrush);
    }
signals:
    void backgroundBrushChanged(const QBrush& brush);
protected:
    void initStyleOption(QStyleOptionViewItem *option, const QModelIndex &index) const override
    {
        QStyledItemDelegate::initStyleOption(option,index);
        option->backgroundBrush = m_backgroundBrush;
    }
private:
    QBrush m_backgroundBrush;
}

You can use it with tableView->setItemDelegateForColumn(0,new BackgroundBrushDelegate(QBrush(Qt::yellow),tableView));

[n-2204]

Actually i already set delegate on column for integer value so if i am now doing using delegate i am not getting color on that column where i set delegate.
so anyother approach to color the columns

[VRonin]

@n-2204 said in Qtableview set background color to some columns:

Actually i already set delegate on column for integer value

You can just mix the two delegates. Can you show us the code of your current delegate?

[n-2204]

How can i mix the delegate?
Delegate for int data ,
Code:

#include "intvalmodel.h"
#include "GAS_tool.h"

intvalmodel::intvalmodel(QObject* parent) :QStyledItemDelegate(parent)
{


}
QWidget* QStyledItemDelegate::createEditor(QWidget* parent, const QStyleOptionViewItem& option,
	const QModelIndex& index) const
{
	QLineEdit* editor = new QLineEdit(parent);
	// QIntValidator* data = new QIntValidator(0, 999);
	 //editor->setValidator(data);
	editor->setValidator(new QIntValidator);
	return editor;

}
void intvalmodel::setEditorData(QWidget* editor, const QModelIndex& index) const
{
	 QString value1 = index.model()->data(index, Qt::EditRole).toString();
 QLineEdit* line = static_cast<QLineEdit*>(editor);
 line->setText(value1);
}
void intvalmodel::setModelData(QWidget* editor, QAbstractItemModel* model, const QModelIndex& index) const
{
	  QLineEdit* line = static_cast<QLineEdit*>(editor);
   QString value1 = line->text();
   model->setData(index, value1);
}
void intvalmodel::updateEditorGeometry(QWidget* editor, const QStyleOptionViewItem& option, const QModelIndex& index) const
{
	editor->setGeometry(option.rect);
}

  delegate = new intvalmodel();
 ui.tableView->setItemDelegateForColumn(1,delegate); 
    ui.tableView->setItemDelegateForColumn(2, delegate);
  ui.tableView->setItemDelegateForColumn(3,delegate); 

i need to set color for column 1,2,3,4,5 as my 3 column used in int delegate how to set color to those also ?

[VRonin]

@n-2204 said in Qtableview set background color to some columns:

QString value1 = line->text();
model->setData(index, value1);

Why do you have an editor for integers but then you save the data as a string? do you have a particular need?

[n-2204]

@VRonin how can i mix two delegates?
I need to enter integer values in column

[VRonin]

@n-2204 said in Qtableview set background color to some columns:

I need to enter integer values in column

You don't need to do anything special. The default delegate already does this.
If, and this is a guess on my part, you are using QStandardItemModel you can solve your problem by never using the constructors QStandardItem(QIcon,QString) or QStandardItem(QString). Just construct an empty item and then call item->setData and pass yor integer to it, do not convert it to a string. You'll see the default delegate (or the modifed version I posted above) will do exactly what you want

[n-2204]

@VRonin so in above share your code how can i add int delegate ?
item->setdata i tried but not working for me
if you have code can you pls share it?
Thanks

[VRonin]

Disclaimer

I think your delegate is doing more harm than good but i'll go along with it anyway.

---

Inside the class you defined in intvalmodel.h add:

public:
void setBrushForColumn(int col, const QBrush& brush);
protected:
void initStyleOption(QStyleOptionViewItem *option, const QModelIndex &index) const override;
private:
QMap<int,QBrush> m_brushes;

now intvalmodel.cpp

#include "intvalmodel.h"
#include "GAS_tool.h"

intvalmodel::intvalmodel(QObject* parent) :QStyledItemDelegate(parent)
{


}
QWidget* QStyledItemDelegate::createEditor(QWidget* parent, const QStyleOptionViewItem& option,
	const QModelIndex& index) const
{
	QLineEdit* editor = new QLineEdit(parent);
	// QIntValidator* data = new QIntValidator(0, 999);
	 //editor->setValidator(data);
	editor->setValidator(new QIntValidator);
	return editor;

}
void intvalmodel::setEditorData(QWidget* editor, const QModelIndex& index) const
{
	 QString value1 = index.model()->data(index, Qt::EditRole).toString();
 QLineEdit* line = static_cast<QLineEdit*>(editor);
 line->setText(value1);
}
void intvalmodel::setModelData(QWidget* editor, QAbstractItemModel* model, const QModelIndex& index) const
{
	  QLineEdit* line = static_cast<QLineEdit*>(editor);
   model->setData(index, line->text().toInt());
}
void intvalmodel::updateEditorGeometry(QWidget* editor, const QStyleOptionViewItem& option, const QModelIndex& index) const
{
	editor->setGeometry(option.rect);
}

void intvalmodel::initStyleOption(QStyleOptionViewItem *option, const QModelIndex &index) const override
    {
        QStyledItemDelegate::initStyleOption(option,index);
        option->backgroundBrush = m_brushes.value(index.column(),option->backgroundBrush);
    }
void intvalmodel::setBrushForColumn(int col, const QBrush& brush){
if(col<0 || col >= columnCount())
return;
m_brushes[col]=brush;
}

Now you can use it:

delegate = new intvalmodel();
delegate ->setBrushForColumn(1,QBrush(Qt::yellow));
delegate ->setBrushForColumn(2,QBrush(Qt::red));
delegate ->setBrushForColumn(3,QBrush(Qt::blue));
 ui.tableView->setItemDelegateForColumn(1,delegate); 
    ui.tableView->setItemDelegateForColumn(2, delegate);
  ui.tableView->setItemDelegateForColumn(3,delegate); 

[n-2204]

@VRonin Thanks

[n-2204]

if just to color one column and no validation on input in column then that done using Qt::BackgroundRole either via setData so need to refer which class QAbstractitem

[n-2204]

@VRonin

class BackgroundBrushDelegate : public QStyledItemDelegate{
    Q_OBJECT
    Q_PROPERTY(QBrush backgroundBrush READ backgroundBrush WRITE setBackgroundBrush NOTIFY backgroundBrushChanged)
    Q_DISABLE_COPY(BackgroundBrushDelegate)
public:
    explicit BackgroundBrushDelegate(QObject *parent = nullptr)
        : QStyledItemDelegate(parent)
    {}
    BackgroundBrushDelegate(const QBrush& brush, QObject *parent = nullptr)
        : QStyledItemDelegate(parent)
        , m_backgroundBrush(brush)
    {}
    const QBrush& backgroundBrush() const { return m_backgroundBrush; }
    void setBackgroundBrush(const QBrush& brush)
    {
        if(m_backgroundBrush==brush)
            return;
        m_backgroundBrush=brush;
        backgroundBrushChanged(m_backgroundBrush);
    }
signals:
    void backgroundBrushChanged(const QBrush& brush);
protected:
    void initStyleOption(QStyleOptionViewItem *option, const QModelIndex &index) const override
    {
        QStyledItemDelegate::initStyleOption(option,index);
        option->backgroundBrush = m_backgroundBrush;
    }
private:
    QBrush m_backgroundBrush;
}

when i am using this code
after applying brushdelegate in that column i am not able to type other then integer can you plz help me how to do ?

[n-2204]

Please help
stuck for some assignment
Thankyou

[JonB]

@n-2204 said in Qtableview set background color to some columns:

after applying brushdelegate in that column i am not able to type other then integer can you plz help me how to do ?

This does not sound like a brush delegate issue. Earlier you have in createEditor() :

editor->setValidator(new QIntValidator);

Make sure that is applying to the column (look at index parameter) where you want an integer, not some other column, at a guess?

[VRonin]

@n-2204 said in Qtableview set background color to some columns:

stuck for some assignment

I'll quote the wise @mrjj

the teacher will catch it and fail them if too much code is just copied.

We gave you 2 possible solutions, one with and one without validator. We even integrated it in your existing code. What more can we do to help?

[n-2204]

Thanks all for you help
May be i asked more that is easy for you ,but as i am new to c++ and qt, so i am not aware of all the concepts.
so for me its little tough in implementation

[Chuck333]

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