如何向 QWidget 添加插槽

How to add a slot to a QWidget?

本文关键字：添加 插槽 QWidget      更新时间：2023-10-16

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 打开。我可以在单击cancelbtn时关闭它，但我无法make_a_box()输入插槽。

我可以在哪里添加此插槽以使此代码正常工作？

这没关系并且运行良好，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，这是不行的：

 // 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不存在插槽make_a_box()，这是一个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);
}
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