Disabling a QCheckbox in a tricky way

Question

I want to make a QCheckBox named "Show Captions" disable another QCheckBox named "Show captions if no title" when the first is checked, but my problem is that how I can make it disabled immediately when the user checks the first checkbox.

SetupSlideShow::SetupSlideShow(QWidget* parent)
    : QScrollArea(parent), d(new SetupSlideShowPriv)
{
    QWidget* panel = new QWidget(viewport());
    setWidget(panel);
    setWidgetResizable(true);

    QVBoxLayout* layout = new QVBoxLayout(panel);

    d->showComment = new QCheckBox(i18n("Show captions"), panel);
    d->showComment->setWhatsThis( i18n("Show the image caption at the bottom of the screen."));

    d->showTitle = new QGroupBox(i18n("Show title"), panel);
    d->showTitle->setWhatsThis( i18n("Show the image title at the bottom of the screen."));
    d->showTitle->setCheckable(true);

    d->showCapIfNoTitle = new QCheckBox(i18n("Show captions if no title"), panel);
    d->showCapIfNoTitle->setWhatsThis( i18n("Show the image caption at the bottom of the screen if no titles existed."));
    QVBoxLayout *vbox = new QVBoxLayout;
    vbox->addWidget(d->showCapIfNoTitle);
    d->showTitle->setLayout(vbox);
    layout->addWidget(d->showLabels);
    layout->addWidget(d->showComment);
    layout->addWidget(d->showTitle);
}

If the buttons should be mutually exclusive, use radio buttons. And/or use a QButtonGroup. — Frank Osterfeld, Dec 17 '11 at 09:52

score 3 · Accepted Answer · answered Dec 17 '11 at 16:17

3

Doesn't this work?

connect(d->showComment, SIGNAL(toggled(bool)), d->showCapIfNoTitle, SLOT(setDisabled(bool)));

answered Dec 17 '11 at 16:17

Daggerstab

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What if I also want to uncheck the "Show captions if no titles" checkbox when the "Show captions" checkbox is checked with the slot (setChecked(bool))? – Wazery Dec 18 '11 at 02:06
AFAIK, for that there's no default slot. (I checked the documentation. The 4.8 docs don't have links pointing to the inherited members like in 4.7, which is annoying and will probably trip some newbies.) – Daggerstab Dec 18 '11 at 07:52
You need to either define a new slot in SetupSlideShow with a bool parameter that calls d->showCapIfNoTitle->setChecked() with the opposite value, or subclass QCheckBox and add a setUnchecked(bool) slot. :) – Daggerstab Dec 18 '11 at 07:55

Arnold Spence · Answer 2 · 2011-12-17T03:58:59.957

The call to paintEvent() isn't really doing anything for you regarding immediacy. Nothing will be repainted until control returns to the event loop (after your constructor exits). It is more typical to call update() but even this is unnecessary when changing the properties of built in widgets.

To link the check boxes, define a slot for the stateChanged() signal of showComment, connect the signal to your slot in your constructor above (by calling connect(), and in that slot, call d->showCapIfNoTitle->setCheckState(d->showComment->checkState()).

Disabling a QCheckbox in a tricky way

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