I create a QPushButton instance before ui->setupUi(this), And this button wont clicked

[NULL_NULL]

as title says, in Qt6.6.1, I add a private (QPushButton *) member in MainWindow and created in the construct list.
code is shown below:

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
    , m_button(new QPushButton("KSKSKSKSK", this))
{
    ui->setupUi(this);
    qDebug() << "object: "<< this <<"is created!";
    // LetsBegin();
    m_button->setGeometry(10,20,300,100);
    QObject::connect(m_button, &QPushButton::clicked,qApp, &QApplication::quit);
}

however when i run this, this button cant be clicked, and no apparence changing even when cursor move through.

by search some other website, i find that ui->setupUi(this) sort of "cover" those QWidget created before this line

I wonder if there is any way to "re_activate" this m_button？
Or i have to create this instance after ui->setupUi(this) anyway?

[NULL_NULL]

I changed ths init method by using m_button( (ui->setupUi(this), new QPushButton("KSKSKSKSK", this))), this seems worked(mainly becase i declear m_button after ui)
but still not a solution since this way only allow me to use construct list rather than create instance before ui->setupUi(this)

[Axel Spoerl]

@NULL_NULL
m_buttonis directly parented to MainWindow, which at this point doesn't have a central widget. That's added (amongst other things) in setupUi(). Hard to say where and why exactly things go wrong, but it's somewhere there.

It'll be better to construct the button without a parent in the first place:

, m_button(new QPushButton("KSKSKSKSK"))

You can add it after calling setupUi(), e.g. with

m_button->setParent(centralWidget());

or by adding it to a layout with

ui->anyLayout->addWidget(m_button);

[jsulm]

This post is deleted!