Enumerate Children Push Buttons from a Window Handle

Chris31

Hello,

I would like to enumerate the push buttons from a main window handle.

In the sample below (Win32 api FindWindow() to get the main window handle, just for testing but I will have to use it in the final application), the foreach loop gives : 1 QRubberBand instead of the 2 QPushButtons.
Why ?

Thanks.

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#include <QtWidgets/QMainWindow>
#include <QtWidgets/QApplication>
#include <QtWidgets/QPushButton>
#include <QtWidgets/QHBoxLayout>

#include <Windows.h>

int main(int argc, char *argv[])
{
QApplication app(argc, argv);

QMainWindow *window = new QMainWindow();
window->setWindowTitle(QString::fromUtf8("Test QPushButtons"));
window->resize(500,300);

QPushButton* button1 = new QPushButton("Button 1");
QPushButton* button2 = new QPushButton("Button 2");

button1->setSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding);
button2->setSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding);

QWidget* centralWidget = new QWidget(window);
centralWidget->setSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding);

QHBoxLayout* layout = new QHBoxLayout(centralWidget);
layout->addWidget(button1);
layout->addWidget(button2);

window->setCentralWidget(centralWidget);
window->show();

HWND hWnd = FindWindow(NULL, L"Test QPushButtons");

if (hWnd)
{
QWidget* widget = QWidget::find((WId)hWnd);

QList<QWidget*> widgets = widget->findChildren<QWidget*>();
foreach (QWidget *widget, widgets)
{
widget->setStyleSheet("background-color:black;");
}
}

return app.exec();
}
@

ckakman

Hi,

I don't know why you need FindWindow. You can get your buttons with:
@
window->findChildren<QPushButton*>();
@

findChild() and findChildren() are QObject's members. So any QObject-derived class can look for its children.

Chris31

window->findChildren is same as widget->findChildren,
but I saw it is the foreach loop which doesn't work, because I can see by debugging all the windows in widgets (QRubberBand, QObject and the 2 QPushButtons)

ckakman

foreach works just fine. If you ask for all widgets, you get all widgets.

You are looking at the wrong place in may one line of sample code. Note that I have specified which type of children I am looking for (hint: look between < and >):
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window->findChildren<QPushButton*>();

or

widget->findChildren<QPushButton*>();
@