How to simply change the background colour of a cell inside a TableView

[G4bandit]

@VRonin

Hi,

first thks so far for your expanded code example.

I am trying to understand with small steps so I wrote this code and hoped see something inside the QTableView. But unfortunatelly nothing happens.

   QSortFilterProxyModel* proxyModel = new QSortFilterProxyModel(this);
   proxyModel->setSourceModel(TblModel);

      TblModel->setData(proxyModel->index(0,0),QBrush(Qt::red),Qt::BackgroundRole);

TblModel is a QSqlTableModel Object which I generate dircetly inside the constructor.

[VRonin]

@G4bandit said in How to simply change the background colour of a cell inside a TableView:

TblModel is a QTableModel

• There's no such thing as QTableModel in Qt, you have to be a little more specific. If you are talking about QSqlTableModel then the problem is here. It will reject everything other than Qt::EditRole. That's the reason I suggested using ExtraRolesProxyModel in between
• Are you setting the model on the view? view->setModel(proxyModel);

P.S.
It's not a bad idea to wrap setData, insert*, remove* and move* calls in a Q_ASSUME to make sure they actually did what you think they should do

[G4bandit]

@VRonin said in How to simply change the background colour of a cell inside a TableView:

Are you setting the model on the view? view->setModel(proxyModel);

I have changed the code to this:

   QSortFilterProxyModel* proxyModel = new QSortFilterProxyModel(this);
   proxyModel->setSourceModel(TblModel);
   ui->TV_DBOut->setModel(proxyModel);

      TblModel->setData(proxyModel->index(0,0),QBrush(Qt::red),Qt::BackgroundRole);

But I guess strongly that it is not what you have meant or at all that it is more complex.

Like you said in your post before:

1. Add this proxy between your model and your view
   I can not follow you, - I am a bloody newbie.

[VRonin]

The main question is: what type is TblModel?

[G4bandit]

@VRonin said in How to simply change the background colour of a cell inside a TableView:

The main question is: what type is TblModel?

Sry, yes it is of QSqlTableModel.

[VRonin]

Then TblModel->setData will return false for every role except Qt::EditRole so basically TblModel->setData(proxyModel->index(0,0),QBrush(Qt::red),Qt::BackgroundRole); will do absolutely nothing.

You need something that handles the other roles that QSqlTableModel ignores. Enter https://pastebin.com/gmNCuUFk

[G4bandit]

@VRonin

I agree with you TblModel->setData returns false.

But my main issue still that I am not able to combine all your information/hints/code parts to one working unit.

1:
I have created a header file with the content of "https://pastebin.com/gmNCuUFk"
Do not know what to do with it.

2:
and I also tried to run your code posted on
VRonin 15. Dez. 2017, 10:31

3:
And this point
VRonin: 1.Add this proxy between your model and your view
Do not know how to

[VRonin]

@G4bandit said in How to simply change the background colour of a cell inside a TableView:

Do not know how to

It's the same as

QSortFilterProxyModel* proxyModel = new QSortFilterProxyModel(this);
   proxyModel->setSourceModel(TblModel);
   ui->TV_DBOut->setModel(proxyModel);

but instead of QSortFilterProxyModel use ExtraRolesProxyModel

[G4bandit]

I got it!!!

SUCESS :D

Thanks a lot

[G4bandit]

If someone ask how to change the color of headers,- here is a helpful link:

https://stackoverflow.com/questions/32147213/how-to-change-the-background-color-from-the-headerhorizontal-vertical-qtable#32147945

tview->model()->setHeaderData(0,Qt::Horizontal,QBrush(QColor("red")),Qt::BackgroundRole);
tview->show();

QApplication::setStyle(QStyleFactory::create("Fusion"));

The last line was on my PC (Win) necessary to get the effect.

[paul_espinosa]

@G4banditi need to do somo simililar can help me please , i cant understand

[VRonin]

I now implemented a generic proxy for this, I called it Role Mask Proxy Model. I have an example that changes the background, it uses QStringListModel but it's exactly the same with other base models

[paul_espinosa]

@VRonin so mucth thanks , wonderfull library, i can do

[paul_espinosa]

if i use a QSqlRelationalTableModel, Role Mask Proxy Model works????

[VRonin]

Yes, works on any model

[paul_espinosa]

@VRonin thanks for your help, now i have a problem, i can not save the data of my QSqlTableModel , i used the example exem_rolemaskeditablesql.cpp i can edit the data but i can not save,

[VRonin]

If you call addMaskedRole passing either Qt::DisplayRole or Qt::EditRole any change will stay in the proxy and not be passed to the source model.

You should only mask the roles that you need, in this case Qt::BackgroundRole.

If it's still not clear, please post us the code using RoleMaskProxyModel and we'll be more specific on the changes to make