Centering QComboBox in table cell

gabor53

Hi,
My QComboBox, which is created by my custom delegate, is placed in a table. Currently it is aligned to the top of the cell. How can I center the QComboBox in the cell? The current code is:

QWidget* WhatFixViewDelegate::createEditor(QWidget* parent, const QStyleOptionViewItem& option, const QModelIndex& index) const {

  Q_UNUSED(option);
  Q_UNUSED(index);
  QComboBox* whatComboEditor = new QComboBox(parent);
  whatComboEditor->setFrame(true);
  whatComboEditor->setStyleSheet("background-color:rgb(255,217,229)");
  whatComboEditor->setEditable(true);
  whatComboEditor->setMaximumWidth (100);
  whatComboEditor->setMinimumWidth (100);
  whatComboEditor->setMaximumHeight (20);
  whatComboEditor->setMinimumHeight (20);

  QSqlQuery queryLoadWhat("SELECT What FROM  What_Table ORDER BY What asc", db);

  while(queryLoadWhat.next()) {
    QString whatItem = queryLoadWhat.value(0).toString();

    whatComboEditor->addItem(whatItem);
  }
  return whatComboEditor;
}

Thank you.

raven-worx

@gabor53
easiest would be to wrap the combobox within a separate QWIdget with a layout where you add the combobox centered.

gabor53

@raven-worx
I added the following:

 QComboBox* whatComboEditor = new QComboBox(parent);

  whatComboEditor->setFrame(true);
  whatComboEditor->setStyleSheet("background-color:rgb(255,217,229);"
                                );
  whatComboEditor->setEditable(true);
  whatComboEditor->setMaximumWidth (100);
  whatComboEditor->setMinimumWidth (100);
  whatComboEditor->setMaximumHeight (30);
  whatComboEditor->setMinimumHeight (30);

  whatComboEditor->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);

  QGridLayout* whatLayout = new QGridLayout(parent);

  whatLayout->setSpacing (0);
  whatLayout->setContentsMargins (0, 30, 0, 0);

  whatLayout->setAlignment (whatLayout, Qt::AlignCenter);
  whatLayout->addItem (new QSpacerItem(100, 30, QSizePolicy::Preferred, QSizePolicy::Expanding), 0, 0);
  whatLayout->addWidget (whatComboEditor, 1, 1, Qt::AlignBottom);

Right now the QComboBox is floating over another cell. How can I move it to the right position (in the middle of the appropriate cell)?

raven-worx

@gabor53 said in Centering QComboBox in table cell:

Right now the QComboBox is floating over another cell. How can I move it to the right position (in the middle of the appropriate cell)?

I dont understand?
What are you dong with whatLayout? Do you set it to any widget?
Also i do not see the wrapper widget in your code.

gabor53

@raven-worx
Now I have this:

 QComboBox* whatComboEditor = new QComboBox(parent);

  whatComboEditor->setFrame(true);
  whatComboEditor->setStyleSheet("background-color:rgb(255,217,229);"
                                );
  whatComboEditor->setEditable(true);
  whatComboEditor->setMaximumWidth (100);
  whatComboEditor->setMinimumWidth (100);
  whatComboEditor->setMaximumHeight (30);
  whatComboEditor->setMinimumHeight (30);

  QGridLayout* whatLayout = new QGridLayout;

  whatComboEditor->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);

  whatLayout->addWidget (whatComboEditor, 1, 0, 1, 1, Qt::AlignCenter);

  QWidget* w = new QWidget();
  w->setLayout (whatLayout);

No error message but no QComboBox in the field either. Do I need to bind widget w to the table cell? If so how? Thank you.

raven-worx

@gabor53
you need to set the parent widget (the passed in parameter) to the widget (w) you return

gabor53

@raven-worx
I made the following changes:

QWidget* WhatFixViewDelegate::createEditor(QWidget* w, const QStyleOptionViewItem& option, const QModelIndex& index) const {

  Q_UNUSED(option);
  Q_UNUSED(index);

    QComboBox* whatComboEditor = new QComboBox(w);
  QGridLayout* whatLayout = new QGridLayout;
  whatComboEditor->setFrame(true);
  whatComboEditor->setStyleSheet("background-color:rgb(255,217,229);"
                                );
  whatComboEditor->setEditable(true);

  whatComboEditor->setMaximumWidth (100);
  whatComboEditor->setMinimumWidth (100);
  whatComboEditor->setMaximumHeight (30);
  whatComboEditor->setMinimumHeight (30);

  whatComboEditor->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);

  whatLayout->addWidget (whatComboEditor, 1, 0, 1, 1, Qt::AlignCenter);
 w->setLayout (whatLayout);

  QSqlQuery queryLoadWhat("SELECT What FROM  What_Table ORDER BY What asc", db);

  while(queryLoadWhat.next()) {
    QString whatItem = queryLoadWhat.value(0).toString();

    whatComboEditor->addItem(whatItem);
  }
  return (w);
}

Now the QComboBox appears, but at the bottom of the cell above. Is there anything else I need to change?

raven-worx

@gabor53 said in Centering QComboBox in table cell:

Now the QComboBox appears, but at the bottom of the cell above. Is there anything else I need to change?

then you are probably opening it on the wrong index?
Please check the index which is passed to the createEditor() method if it's correct.

gabor53

@raven-worx
I checked the index:

 qDebug() << "Entered WhatFixViewDelegate createEditor. ";
  qDebug() << "whatfixviewdelegate index: " << index;

and it is correct.
The QComboBox is not exactly on the bottom of the cell above, a small portion is on the top of the correct cell.
I painted w blue:

 w->setStyleSheet ("background-color: blue");

I learned, that widget w is always in the right cell, but the QComboBox is always in between the 2 specific cells no matter, where w is. What did I do incorrectly?

raven-worx

@gabor53
try:

whatLayout->setSpacing(0);
whatLayout->setContentsMargins(0,0,0,0);

gabor53

@raven-worx
I tried, but the result is the same.

raven-worx

@gabor53
then i have no idea left.
Can you post a screenshot, maybe this clears something up.

gabor53

@raven-worx
Here is the image! image url)
The QComboBox is supposed to be centered in the middle of the "girl" field.

raven-worx

@gabor53
now i see, you should create a wrapper widget. Not reuse the passed widget pointer (which is actually the parent widget = viewport widget).
What you actually have already done in the code before... but again left out in the next post of yours?!?

QWidget* WhatFixViewDelegate::createEditor(QWidget* parent, const QStyleOptionViewItem& option, const QModelIndex& index) const {
  Q_UNUSED(index);

   QWidget* w = new QWidget( parent );

    QComboBox* whatComboEditor = new QComboBox(w);
  whatComboEditor->setFrame(true);
  whatComboEditor->setStyleSheet("background-color:rgb(255,217,229);" );
  whatComboEditor->setEditable(true);

  whatComboEditor->setMaximumWidth (100);
  whatComboEditor->setMinimumWidth (100);
  whatComboEditor->setMaximumHeight (30);
  whatComboEditor->setMinimumHeight (30);

  whatComboEditor->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);

  QVBoxLayout* whatLayout = new QVBoxLayout;
  whatLayout->addWidget (whatComboEditor, 0, Qt::AlignCenter);

  w->setLayout (whatLayout);

   QSqlQuery queryLoadWhat("SELECT What FROM  What_Table ORDER BY What asc", db);

   while(queryLoadWhat.next())
   {
       QString whatItem = queryLoadWhat.value(0).toString();
       whatComboEditor->addItem(whatItem);
   }

   w->setGeometry( option.rect ); // don't know if this is really needed - try with and without it 

   return w;
}

gabor53

@raven-worx
It's much better now without

   w->setGeometry( option.rect );

It looks like this now:

I used

whatLayout->setMargin (2);

to center.
Thank you for your help.