Set widget background color

Question

I use QCheckBox in QTableWidgetCell

QWidget *widget = new QWidget();
QCheckBox *checkBox = new QCheckBox();
QHBoxLayout *layout = new QHBoxLayout(widget);
layout->addWidget(checkBox);
layout->setAlignment(Qt::AlignCenter);
layout->setContentsMargins(0, 0, 0, 0);
widget->setLayout(layout);
table->setCellWidget(0, 0, widget);

How can I change cell background?

Solution 1

The code:

widget->setStyleSheet("background-color: red");

works fine but you need to set the style for every container widget you add to your table:

So in order to see the change you need the following code:

QWidget *widget = new QWidget();
widget->setStyleSheet("background-color: red");
QCheckBox *checkBox = new QCheckBox();
QHBoxLayout *layout = new QHBoxLayout(widget);
layout->addWidget(checkBox);
layout->setAlignment(Qt::AlignCenter);
layout->setContentsMargins(0, 0, 0, 0);
widget->setLayout(layout);

QWidget *widget2 = new QWidget();
widget2->setStyleSheet("background-color: red");
QCheckBox *checkBox2 = new QCheckBox();
QHBoxLayout *layout2 = new QHBoxLayout(widget2);
layout2->addWidget(checkBox2);
layout2->setAlignment(Qt::AlignCenter);
layout2->setContentsMargins(0, 0, 0, 0);
widget2->setLayout(layout);

ui->tableWidget->setCellWidget(0, 0, widget);
ui->tableWidget->setCellWidget(0, 1, widget2);

And the result will be:

Solution 2

You should try this:

checkBox->setStyleSheet("background-color: red;");

If you want to specify it more generally, write the classtype in the CSS to indicate which class in the hierarchy should handle the flag. This could look something like this then:

QWidget { background-color: red; }

Solution 3

If you want to change cell background, not a widget, use setBackground() method:

QCheckBox *checkBox = new QCheckBox("example");
QWidget *widget = new QWidget();
QHBoxLayout *layout = new QHBoxLayout(widget);
layout->addWidget(checkBox);
layout->setAlignment(Qt::AlignCenter);
layout->setContentsMargins(0, 0, 0, 0);
widget->setLayout(layout);
ui->tableWidget_2->setCellWidget(0,0,widget);
ui->tableWidget_2->item(0, 0)->setBackground(Qt::red);//this line should be

In this case all your cell will be red (without white lines around checkbox).