QCheckBox not displaying checked state

[CybeX]

Hi all

I have been developing a GUI, and have run into an issue (or possible bug) with a QCheckBox.

Problem

Adding a QCheckBox component to my form, compiling and running it has no issues. However, when clicking on the checkbox, no visible feedback is displayed.

I added a listener for the clicked(bool) signal It is used in the debug output to display the current state, which does change.

More Information

Only 3 settings are changed on the checkbox:

1. Component Text
2. Component Name
3. Component Checkedstate : Checked.

I added another checkbox to the page, recompiled and ran it without changing anything. Again, this new checkbox does not respond to changes.

Furthermore, I created a new project, added only a checkbox, compiled and ran it. Had no issues displaying the state change. Must be an issue with my project.

Output of stateChanged(int) and clicked(bool) signals: (qDebug() output)

QCHECKBOX STATE (stateChanged):  "2"
QCHECKBOX STATE (clicked):  "checked"
QCHECKBOX STATE (stateChanged):  "0"
QCHECKBOX STATE (clicked):  "unchecked"
QCHECKBOX STATE (stateChanged):  "2"
QCHECKBOX STATE (clicked):  "checked"
QCHECKBOX STATE (stateChanged):  "0"
QCHECKBOX STATE (clicked):  "unchecked"

If any additional project info is required, feel free to leave a comment

[sierdzio]

Weird case. Are you using QSS by any chance? Perhaps you ran into https://bugreports.qt.io/browse/QTBUG-48023

[CybeX]

@sierdzio you are correct, after much searching, I found out that in the CSS, setting the QCheckBox::indicator color will mess with the checkbox mark.

I will post a solution shortly

Thanks for asking though!

[CybeX]

Here is a possible solution for solving this "missing check/mark" issue.

I implemented the CSS "indicator" solution I got from this qt form post which is problematic.

Sources of solution:

• Doc page: here
• Implementation: here

QPalette p = ui->checkBox->palette();
p.setColor(QPalette::Active, QPalette::Base, QColor(255, 255, 255));
p.setColor(QPalette::Button, QColor(255, 255, 255));
ui->checkBox->setAutoFillBackground(true);
ui->checkBox->setPalette(p);

QColor(255, 255, 255)

refers to your desired background color, possibly the same color as your window background, etc.

QPallete::Active,  QPalette::base

refers to the active checkbox's background (the white box background)

QPalette::Button

refers to the "actual background" (behind the checkbox and the checkbox text)

Hope this helps!