Qt之QCheckBox

构造一个复选框QCheckBox，然后使用setTristate()开启三态模式。

QCheckBox *pCheckBox = new QCheckBox(this);
m_pLabel = new QLabel(this);

m_pLabel->setText("Click CheckBox...");
pCheckBox->setText(QString::fromLocal8Bit("三态复选框"));

// 开启三态模式
pCheckBox->setTristate();

// 连接信号槽
connect(pCheckBox, SIGNAL(stateChanged(int)), this, SLOT(onStateChanged(int)));

槽函数，判断当前复选框状态，其中包括：选中（Qt::Checked）、半选（Qt::PartiallyChecked）、未选中（Qt::Unchecked）。

void MainWindow::onStateChanged(int state)
{
if (state == Qt::Checked) // "选中"
{
m_pLabel->setText("Checked");
}
else if(state == Qt::PartiallyChecked) // "半选"
{
m_pLabel->setText("PartiallyChecked");
}
else // 未选中 - Qt::Unchecked
{
m_pLabel->setText("Unchecked");
}
}

QSS复选框样式。
QCheckBox{
spacing: 5px;
color: white;
}
QCheckBox::indicator {
width: 17px;
height: 17px;
}
QCheckBox::indicator:enabled:unchecked {
image: url(:/Images/checkBox);
}
QCheckBox::indicator:enabled:unchecked:hover {
image: url(:/Images/checkBoxHover);
}
QCheckBox::indicator:enabled:unchecked:pressed {
image: url(:/Images/checkBoxPressed);
}
QCheckBox::indicator:enabled:checked {
image: url(:/Images/checkBoxChecked);
}
QCheckBox::indicator:enabled:checked:hover {
image: url(:/Images/checkBoxCheckedHover);
}
QCheckBox::indicator:enabled:checked:pressed {
image: url(:/Images/checkBoxCheckedPressed);
}
QCheckBox::indicator:enabled:indeterminate {
image: url(:/Images/checkBoxIndeterminate);
}
QCheckBox::indicator:enabled:indeterminate:hover {
image: url(:/Images/checkBoxIndeterminateHover);
}
QCheckBox::indicator:enabled:indeterminate:pressed {
image: url(:/Images/checkBoxIndeterminatePressed);
}

连接stateChanged()信号和槽函数，当用户点击复选框时，状态发生改变就会调用槽函数。

根据以上样式可写为：
AirFrame QCheckBox#switch_Button::indicator:unchecked
{
image: url(://resource/area/checkbox/close.png);
}

AirFrame QCheckBox#switch_Button::indicator:checked
{
image: url(://resource/area/checkbox/open.png);
}

以上是更改使用的。