我想使用 Qt 框架在新小部件中添加标签

Question

This is my code :

void maquette::on_btn_edit_clicked()
{
    QWidget* wdg = new QWidget;
    wdg->resize(320, 340);
    wdg->setWindowTitle("Modiffier");
    QLabel label1("matricule", wdg);
    label1.setGeometry(100, 100, 100, 100);
    wdg->show();
}

the window shows up but the label didn't show

Answer 1

void maquette::on_btn_edit_clicked()
{
 QWidget *wdg = new QWidget;
 wdg->resize(320,340);
 wdg->setWindowTitle("Modiffier");
 QLabel *label1 = new QLabel("matricule",wdg);
 label1->setGeometry(100, 100, 100, 100);
 wdg->show();
}

Answer 2

You can either add the QLabel using parenting. as mentioned before.

QLabel *label1 = new QLabel("matricule",wdg);

or

QLabel *label1 = new QLabel("matricule");
label1->setParent(wdg);

This will make the widget float inside its parent.

You can also add the QLabel to a layout that has been assigned to the QWidget.

QVBoxLayout* layout = new QVBoxLayout();
wdg->setLayout(layout);
QLabel *label1 = new QLabel("matricule");
layout->addWidget(label1);

This will add the widget to the layout. The layout will control how the child widgets are laid out.