如何将插槽添加到 QWidget？

Question

我有一个 QMainWindow，它有一个 QAction，其信号 triggered() 连接到插槽 about2()。

...
connect(mAboutAction2, SIGNAL(triggered()), this, SLOT(about2()));
...


void occQt::about2()  //UI
{
    QWidget* pWidget = new QWidget;
    QPushButton* okbtn = new QPushButton(tr("ok"));
    QPushButton* cancelbtn = new QPushButton(tr("cancel"));
    btnlayout->addWidget(okbtn);
    btnlayout->addWidget(cancelbtn);
    dlglayout->setMargin(50);
    dlglayout->addLayout(gridlayout);
    dlglayout->addStretch(40);
    dlglayout->addLayout(btnlayout);
    pWidget->setLayout(dlglayout);
    pWidget->setWindowTitle(tr("Make a Box by custom."));
    pWidget->show();
    connect(okbtn, SIGNAL(clicked()), pWidget, SLOT(make_a_box()));
    connect(cancelbtn, SIGNAL(clicked()), pWidget, SLOT(close()));
}

void occQt::make_a_box()
{
    TopoDS_Shape aTopoBox = BRepPrimAPI_MakeBox(3.0, 4.0, 95.0).Shape();
    Handle_AIS_Shape anAisBox = new AIS_Shape(aTopoBox);

    anAisBox->SetColor(Quantity_NOC_AZURE);

    mContext->Display(anAisBox);
}

当我运行插槽 about2() 时，UI 会打开。点击cancelbtn可以关闭它，但是我无法进入插槽make_a_box()。

我可以在哪里添加此插槽以使此代码正常工作？

Answer 1

这没问题，运行良好，因为您使用的插槽位于正确的位置：在您的 occQt 类中。

// You connect the signal FROM the action TO "this", i.e. your class
connect(mAboutAction2, SIGNAL(triggered()), this, SLOT(about2()));

void occQt::about2()  //UI
{

    QWidget* pWidget = new QWidget;
    QPushButton* okbtn = new QPushButton(tr("ok"));
    QPushButton* cancelbtn = new QPushButton(tr("cancel"));
    btnlayout->addWidget(okbtn);
    btnlayout->addWidget(cancelbtn);
    dlglayout->setMargin(50);
    dlglayout->addLayout(gridlayout);
    dlglayout->addStretch(40);
    dlglayout->addLayout(btnlayout);
    pWidget->setLayout(dlglayout);
    pWidget->setWindowTitle(tr("Make a Box by custom."));
    pWidget->show();

现在不行了：

 // You connect the signal FROM the button to pWidget, which doesn't have a slot make_a_box()
 connect(okbtn, SIGNAL(clicked()), pWidget, SLOT(make_a_box()));

pWidget 的插槽 make_a_box() 不存在，QWidget。您正在尝试将信号连接到不存在的插槽。

您必须在 occQt 类中定义此插槽，并将按钮的信号 clicked() 连接到您的类中的插槽：

// Now, you connect the signal FROM the button to "this", which is your class and has a slot make_a_box()
connect(okbtn, SIGNAL(clicked()), this, SLOT(make_a_box()));

在您的 .h 文件中，您将拥有：

private slots : 
    void make_a_box();

在您的 .cpp 文件中：

void occQt::make_a_box()
{
    TopoDS_Shape aTopoBox = BRepPrimAPI_MakeBox(3.0, 4.0, 95.0).Shape();
    Handle_AIS_Shape anAisBox = new AIS_Shape(aTopoBox);

    anAisBox->SetColor(Quantity_NOC_AZURE);

    mContext->Display(anAisBox);
}